Author name code: osterbrock
ADS astronomy entries on 2022-09-14
author:"Osterbrock, Donald E."
------------------------------------------------------------------------
Title: Frank Ross, his Ross Lens Design, and the Lick Observatory
20-inch Astrograph
Authors: Osterbrock, Donald E.
Bibcode: 2007JHA....38...31O
Altcode:
No abstract at ADS
Title: Early Photographs of the Distant Sierra Nevada Mountains
Taken from Lick Observatory
Authors: Osterbrock, Donald E.
Bibcode: 2006JAHH....9..181O
Altcode:
During World War I, a group of American chemists, physicists
and astronomers developed processes for greatly increasing the
infrared sensitivity of photographic emulsions, for long-distance
reconnaissance from airplanes or the ground. After the war Lick
Observatory astronomers, beginning with C.D. Shane and Mary Lea Heger,
used long-focal-length astronomical cameras and these hypersensitization
methods to photograph the distant Sierra Nevada range, including
Yosemite Valley and Half Dome, nearly one hundred miles away across
the Central Valley of California. These pictures, widely exhibited
and admired, strengthened links between astronomers, the Eastman Kodak
Company and the public.
Title: Seth Nicholson's First Satellite Discovery: Jupiter IX and
His Orbit for It
Authors: Osterbrock, Donald E.
Bibcode: 2006AAS...209.2303O
Altcode: 2006BAAS...38R.931O
Seth B. Nicholson was a graduate astronomy student at the University
of California in Berkeley when he discovered his first satellite in
1914. He was later to discover three more, after he had joined the Mount
Wilson Observatory staff following his PhD in 1915. Nicholson
had begun his thesis on the problem of computing an improved orbit
for J VIII, which had been discovered by Melotte in England in 1908,
a distant irregular satellite like J VI and J VII. Nicholson was taking
photographic plates to measure the position of J VIII in the summer
of 1914 with the Crossley 36-inch reflector of Lick Observatory. He
was a teaching assistant at Berkeley that summer, but would go up
to Mount Hamilton to observe on weekends in the dark of the moon,
traveling by rail, stage (an automobile on a regular schedule between
San Jose and the observatory) and interurban trolley car, and sleeping
in a shed near the Crossley dome. He first saw J IX as a much fainter
object with the same motion as J VIII on a plate he took in late July
1914, and realized it must be another satellite of the giant planet. Nicholson obtained his first orbit of J IX, which had by then become
his new thesis topic, in September, and published a paper on it in early
1915. Its orbit, like that of J VIII, was retrograde and irregular,
but it was considerably fainter. Nicholson, a loyal student of Armin
O. Leuschner, the head of the Berkeley Astronomy Division, used his
teacher's "short method" (or analytic method) to calculate the orbit.
Title: Frank Ross's Early Orbits of the First Irregular Satellites
of Saturn and Jupiter
Authors: Osterbrock, Donald E.
Bibcode: 2006AAS...209.3304O
Altcode: 2006BAAS...38..950O
Frank E. Ross, later the inventor of the wide-angle lens, photographic
photometer, and correcting lens for large reflecting telescopes,
developed for the 200-inch, that bear his name, was also an expert
on celestial mechanics. After earning his PhD at Berkeley in 1901,
he worked in Washington as chief assistant to Simon Newcomb, the
leading astronomer of his time, until the latter's death in 1909. W. H. Pickering, who had discovered Phoebe, the first distant,
irregular satellite of Saturn, was unable to calculate an orbit for
it. He asked Newcomb to do it, but the "grim dean of American astronomy"
was too busy, and turned the task over to Ross to do, mostly on his
own time. The young assistant succeeded, but spent many sleepless
nights on the job. He and his brother Walter were also running a
cigar store in Washington at the time. Charles D. Perrine at Lick
Observatory discovered J VI and J VII, the first two similar satellites
of Jupiter, in 1904 and 1905, and could not obtain satisfactory orbits
for them either, even with Director W. W. Campbell's help. Ross then
calculated their orbits also, again at a tremendous cost of effort. He
used log tables, pencil and paper, and a simple adding machine for his
computing tasks, as all "computers" (persons) did at that time. These
three satellites were the first to be discovered by photography.
Title: Frank Ross's Early Direct Photographs of Venus and His
Interpretation of Them
Authors: Osterbrock, Donald E.
Bibcode: 2006DPS....38.2601O
Altcode: 2006BAAS...38..524O
Frank Ross was an outstandingly creative astronomical "jack of many
trades" (Monet) or "cat with nine astronomical lives". After joining
the Yerkes Observatory faculty in 1924, at age 50, he took a long
series of almost nightly direct photographs of Venus in 1927 with the
Mount Wilson 60-inch and 100-inch reflectors as a guest observer. He
published many of these images in the ApJ in 1928, with his conclusions
on the nature of Venus. Ross discovered markings, seen only in the
ultraviolet images, parallel "belts" indicating rotation. They changed
rapidly. From these photographs he developed a tentative picture of
a deep opaque atmosphere, with high pressure at the surface of the
planet. The changes were due to "violent events" (winds or storms)
in its atmosphere. From spectroscopic results of Slipher, Adams,
StJohn, and Nicholson he took the rotation period to be long. But
bolometric observations of Pettit, Nicholson, Coblentz, and Lampland,
indicated little temperature change between the illuminated and dark
parts of the disk, so it could not be too slow. Ross settled on a
"compromise" rotation period of about 30 days based on the data he
had. The spectroscopic measurements showed there was very little,
if any, H2O or O2 in the atmosphere. Ross
is best known today for his Ross wide-angle camera design, his Ross
high-proper-motion stars, his Ross photometer, and his Ross correctors
for large reflecting telescopes, but his foray into planetary astronomy,
long before the era of radar or close-up imaging and spectroscopy
from space vehicles, was an important first step toward understanding
Venus. His years of experience in laboratory studies of the
properties of photographic plates, developers, and mensuration were
highly important for this work. Equally so were his cheerful, peppery
personality and his close relations with many Mount Wilson and Lowell
Observatory staff members.
Title: Astrophysics of gaseous nebulae and active galactic nuclei
Authors: Osterbrock, Donald E.; Ferland, Gary J.
Bibcode: 2006agna.book.....O
Altcode:
No abstract at ADS
Title: Book review: From nuclear transformation to nuclear fission,
1932 - 1939 / Institute of Physics Publishing, Bristol and
Philadelphia, xii + 304 pp., 2002, ISBN 0-7503-0865-6.
Authors: Osterbrock, Donald E.
Bibcode: 2005JHA....36..245O
Altcode:
No abstract at ADS
Title: Book Review: Den Himmel Fest im Blick: eine Wissenschaftliche
Biografie uber dem Astro-Optiker Bernhard Schmidt / Franz Stein
Verlag, 2002
Authors: Osterbrock, Donald E.
Bibcode: 2005JHA....36..118O
Altcode:
No abstract at ADS
Title: A. A. Michelson's Jovian Galilean-Satellite Interferometer
at Lick Observatory in 1891
Authors: Osterbrock, D. E.
Bibcode: 2004AAS...205.0401O
Altcode: 2004BAAS...36.1340O; 2004AAS...205..401O
Albert A. Michelson, America's first Nobel laureate in physics, measured
the angular diameter of the red supergiant star Betelgeuse in 1920
with Francis G. Pease, using the 100-inch Mount Wilson reflector as
the basis of his stellar interferometer. But he had first published the
concept in 1890 and tested it on celestial objects with a telescope at
Lick Observatory in 1891. He used its 12-inch refractor to measure the
angular diameters of the four Galilean satellites of Jupiter, assisted
at the telescope by W. W. Campbell, then a young astronomer who had
just joined the Lick staff. Edward S. Holden, the Lick director, had
invited Michelson to come to Mount Hamilton and use its telescopes as
a guest observer. Michelson had first tried and proved his method
on artificial circular disks in his laboratory at Clark University,
Worcester, Mass., using a 2-inch "glass." Then in 1889 and 1890 he
hoped to test it at Harvard College Observatory, but apparently the
telescope or the atmospheric conditions did not work out. At Lick he
did achieve success, and his measured angular diameters were nearer to
the true values we know from close-up space measurements of today than
those of any of the top visual observers of the time. Correspondence
in the Lick Archives shows that Michelson intended to come back there
to use its big 36-inch refractor to improve the measurements, but he
never did so. Selections from Michelson's published papers and
photographs of him, the telescope, and the instrument will be posted.
Title: The Mount Wilson-University of California Connection from
Hussey and Seares to Mayall and Olin Wilson
Authors: Osterbrock, D. E.
Bibcode: 2004AAS...205.0103O
Altcode: 2004AAS...205..103O; 2004BAAS...36.1338O
George Ellery Hale, who founded Mount Wilson Solar Observatory,
first visited Lick Observatory in 1890, soon after his graduation from
MIT. After his parents' deaths, when he began openly planning a Yerkes
Observatory ``expedition" to California, Hale's friend James E. Keeler,
then Lick Observatory Director, invited him (in 1899) to locate it on
Mt.Hamilton. Hale thanked him, but replied that sites further south
would have more clear weather. He had probably already decided on Mount
Wilson. There were many close connections between the University of
California and Mount Wilson Observatory from that time right up to
the present. W.J. Hussey was the Lick astronomer who carried
out the official site survey that confirmed Mount Wilson as the best
site. Harold Palmer (UC Astronomy PhD 1903) was the first new staff
member Hale hired, but he only lasted a few months. The two main
reasons for the continuing connection were the geographical proximity
of Pasadena and the Bay Area, and the fact that for many years UC was
the outstanding graduate astronomy department in the country, producing
numerous well trained observational research astronomers. However in the
early years the reasons were more complicated. After Palmer, the next
three hired at MWO were Arthur King, the first UC Physics PhD (1903);
Harold Babcock, (UC Engineering BS 1907); and F.H. Seares (UC Astronomy
BS 1895). Harold Babcock trained his son in astronomy almost from
birth, and Horace (UC Astronomy PhD 1938) joined the MWO staff after
World War II and became its Director in 1964. Palmer and Edward Fath
(UC PhD 1909) were less successful at MWO and soon departed. These and
numerous other MWO astronomers with UC backgrounds will be mentioned,
and their careers discussed.
Title: Erratum: The California-Michigan axis in American astronomy
Authors: Osterbrock, Donald E.
Bibcode: 2004JAHH....7...64O
Altcode:
No abstract at ADS
Title: Book Review: Sky and ocean joined: The U.S. Naval Observatory,
1830 - 2000 / Cambridge University Press, New York, xvi + 610 pp.,
2003, ISBN 0-521-81599-1.
Authors: Osterbrock, Donald E.
Bibcode: 2004JHA....35..237O
Altcode:
No abstract at ADS
Title: Obituary: Ernest Hurst Cherrington, Jr., 1909-1996
Authors: Osterbrock, Donald E.
Bibcode: 2003BAAS...35.1458O
Altcode:
Ernest H. Cherrington, Jr., a long-time member of the AAS, died in San
Jose, California on 13 July 1996, following a long illness. He had a
short but active career as a research astronomer at Perkins Observatory
at Ohio Wesleyan University in Delaware, Ohio before World War II, in
which he served as an officer in the Army Air Force. After the war ended
he turned to full-time teaching and administration at the University
of Akron, and then at Hood College in Frederick, Maryland. Ernest
was born on 10 September 1909 in Westerville, Ohio, where his father,
Ernest H. Cherrington, Sr., was a leader in the temperance movement and
publisher of "American Issue", a Prohibitionist magazine. Ernest Jr.'s
mother, Betty Clifford (née Denny) Cherrington, was a homemaker. He was
an outstanding student in high school and at Ohio Wesleyan University,
which he entered in 1927. The little university's Perkins Observatory
with its 69-inch reflector, briefly the second largest telescope in
the United States, had just been built and gone into operation. After
graduating with a BA magna cum laude in astronomy in 1931, Ernest
stayed on one more year and earned his MS with a thesis on the motion
of material in the tail of Comet Morehouse, supervised by Nicholas
T. Bobrovnikoff. In 1932 Ernest entered the University of
California at Berkeley as a graduate student, with a one-year teaching
assistantship in the Astronomical Department. This was followed by
a two-year Lick Observatory Fellowship. In June 1933 he married Ann
McAfee Naylor, who had been a classmate at Delaware High School and
Ohio Wesleyan. Ernest did his PhD thesis on spectrophotometry of the
Mg I b lines in the solar spectrum, using a high-resolution grating
spectrograph on the Berkeley campus, designed by C. Donald Shane, his
adviser. In this thesis, Ernest tested and improved the then current
theory of strong absorption lines in stellar atmospheres. He also spent
several short periods at Lick Observatory on Mount Hamilton, working
in stellar spectroscopy with Joseph H. Moore. After earning his
PhD in 1935, Ernest taught mathematics and astronomy for one year at
Syracuse University, and then in 1936 returned to Ohio Wesleyan as
an assistant astronomer and instructor in physics and astronomy. In
1940 he was promoted to assistant professor. He did good spectroscopic
research on Be stars, especially a long study of the variations in the
spectrum of γ Cas, an unusually active star of this class which he
followed as it threw off several shells. It was a program well suited
to the telescope, spectrograph, and site available to him. Ernest
attended several meetings of the AAS, reported on his research in
oral papers, and published them. However after America entered World
War II he went into the Army Air Force in 1942, serving as a Captain
in the Air Force Training Command. He had an important job directing
ground training of officers, cadets, and enlisted men at various
fields in California and New Mexico. After the war, although
he could have returned to Perkins Observatory, he realized that the
future was not hopeful for astronomical research there, and decided
to switch to academic administration. He was at Centenary College,
Louisiana for two years, 1946--48, and then went to the University of
Akron as professor of astronomy and dean of the College of Liberal Arts
from 1948 to 1960, then of its Graduate Division from 1960 to 1967. He
loved teaching astronomy and continued to do so while holding these
deanships. Ernest was a good writer, and he published several articles
on astronomy and science in the "New York Times Sunday Magazine" and
other mass-circulation magazines in those years. Ernest retired
at Akron in 1967 but moved to Hood College in Frederick, Maryland,
as professor of astronomy, a full-time teaching position with no
administrative duties. Soon after arriving there he published "Exploring
the Moon with Binoculars", a very popular book in the early days of the
NASA program of lunar photography from unmanned space vehicles. All the
ground-based photographs in his book came from Lick Observatory, most
of them taken by Moore and Fred Chappell, with whom he had worked. About
1979 he retired from Hood College and he and his wife moved to San Jose,
near the home of their surviving son, Robert N. Cherrington. Ernest was
always a good family man, devoted to his wife and children. I met Ernest
at his home in San Jose and interviewed him several times in preparation
for the Lick centennial in 1988; he had warm memories of Lick and the
Berkeley Astronomical Department. In 1984 he had updated his book to
"Exploring the Moon through Binoculars and Small Telescopes", with
additional photographs from lunar orbiting vehicles and one taken by
Neil Armstrong of Buzz Aldrin on the moon's surface. Ernest's wife
Ann died in 1988 and he followed her eight years later. There
are about one hundred letters to, from, or about Ernest, written in
the years 1931 to 1948, in the Mary Lea Shane Archives of the Lick
Observatory, McHenry Library, University of California. These letters,
his published papers and book, and Perkins Observatory annual reports,
together with information provided by Robert N. Cherrington and my
own notes and memories of conversations with Ernest and Ann formed
the basis of this obituary article.
Title: The California-Michigan axis in American astronomy
Authors: Osterbrock, Donald E.
Bibcode: 2003JAHH....6..120O
Altcode:
From the beginning of the big-telescope era in American astronomy
there has been a California-Michigan Axis of exchange of astronomers
between these two states. Several of the earliest participants in it
are identified, and their careers are briefly described; some of the
reasons for which it came into existence and survived are discussed.
Title: The High-Resolution Light-polluted Night-Sky Spectrum at
Mount Hamilton, California
Authors: Slanger, T. G.; Cosby, P. C.; Osterbrock, D. E.; Stone,
R. P. S.; Misch, A. A.
Bibcode: 2003PASP..115..869S
Altcode:
Sky spectra were recorded over San Jose at the Lick Observatory
over the 3800-9200 Å spectral range, with a spectral resolution
of 45,000. Strong atomic lines were detected from Al I, Ar I, Hg I,
K I, Li I, Na I, Ne I, Sc I, Sc II, Th I, Th II, and from O I and OH
nightglow features. Spectra are contrasted for observations over San
Jose (west), the zenith direction, and the eastern sky. When observing
in the easterly direction, the emission intensity is still 20%-30%
of that seen toward the west. For a natural and stable terrestrial
nightglow line, O I λ5577, the intensity is comparable in either
direction. A variety of line shapes are observed, reflecting
the outputs of the mélange of pollution sources. A total of 177
identified light-pollution lines were observed, of which more than
half are due to Sc I and Sc II. The Sc I lines show a systematic shift
to longer wavelengths from the expected positions, amounting to an
average of 25 mÅ. This is presumably a consequence of their origin,
high-pressure metal halide lamps. By comparing the intensity of the
strongest pollution lines and continuum (from Na) with the nightglow
O I λ5577 line, a figure of merit for the pollution line intensity
is the equivalent of 4 kR for the atmospheric conditions and viewing
geometry investigated. Lick Observatory Bulletin 1401.
Title: Don Hendrix, master Mount Wilson and Palomar Observatories
optician
Authors: Osterbrock, Donald E.
Bibcode: 2003JAHH....6....1O
Altcode:
Don O. Hendrix, with at most a high-school education and no previous
experience in optics, became an outstanding astronomical optician at
Mount Wilson Observatory. He started making Schmidt-camera optics
for spectrographs there in 1932, and ultimately made them for all
the stellar and nebular spectrographs used at the prime, Newtonian,
Cassegrain, and coudé foci of the 60-inch, 100-inch, and Palomar
Hale 200-inch telescopes. He completed figuring and polishing the
primary 200-inch mirror, and also the Lick Observatory 120-inch primary
mirror. Mount Wilson and Palomar Observatory designers Theodore Dunham
Jr., Rudolph Minkowski, and Ira S. Bowen led the way for many years
in developing fast, effective astronomical spectrographs, based on
Hendrix's skills.
Title: Albert Edward Whitford
Authors: Osterbrock, Donald E.
Bibcode: 2003PhT....56a..67O
Altcode:
No abstract at ADS
Title: Four Big-Telescope Planetary Astronomers of the 1920's at
Mount Wilson, Yerkes, and Lick Observatories
Authors: Osterbrock, D. E.
Bibcode: 2002AAS...201.2116O
Altcode: 2002BAAS...34.1140O
Contrary to current mythology, many professional astronomers tried
to do planetary research before World War II, as Ronald Doel and
I have previously emphasized. Their difficulty was that once the
known planets had been studied with the biggest and best telescopes,
spectrographs, and radiometers there was little more they could
do until some new instrumental development came along, and these
were rare in those years. Two astronomers who observed planets in
the 1920's were Frank Ross, of the Yerkes Observatory faculty, with
the Mount Wilson 60- and 100-inch telescopes, and William H. Wright,
at Lick, with its 36-inch Crossley reflector, which he considered a
big telescope. Both were keenly interested in photographic emulsions
(Ross had been a research physicist at the Eastman Kodak Laboratory),
and when fast new panchromatic films and plates became available in the
1920's they quickly applied them to photographing the planets. Robert
J. Trumpler, also at Lick, used its 36-inch refractor in a combination
of photographic (in the yellow and red spectral regions) and visual
observing to map and describe Martian surface features. All three of
them began planetary observing at the close opposition of Mars in 1924;
they were all mainline scientists who ultimately were elected to the
National Academy of Sciences. All three of them were doing descriptive
work, seeing what was there, and none of them had any theoretical
ideas to check or disprove. Francis G. Pease, more of a telescope
designer and engineer at Mount Wilson, also used its 60- and 100-inch
reflectors, chiefly to take photographs of the planets for illustrations
in books and magazines. They all used fine-grain photographic plates,
but seeing was a problem they could not overcome. Examples of their
planetary photographs, papers, and letters will be posted. Ross and
Trumpler dropped out of planetary astronomy after 1928, but Wright
and Pease continued in it for many years. An interesting sidelight
is that Gerard P. Kuiper, as a young postdoc at Lick, co-authored his
first planetary paper in English with Wright (on Mars).
Title: America's First Carl Sagan: Ormsby MacKnight Mitchel, Pre-Civil
War Astronomer and Lecturer on the Cosmos
Authors: Osterbrock, D. E.
Bibcode: 2002AAS...201.2901O
Altcode: 2002BAAS...34.1150O
In the years before television, videos, radio. movies, or even
loudspeakers, Ormsby MacKnight Mitchel (1809-1862) was the best-known
popularizer of astronomy and the scientific study of the universe in
nineteenth-century America. Each winter he traveled the country by
railroad, steamer, and stagecoach, speaking to large paying crowds
in principal cities from Boston, New York, and Philadelphia through
Cincinnati to New Orleans on the cosmos and our place in it, with
special attention to possible inhabitants of planers orbiting other
stars. Mitchel had much the same attraction as Sagan did in our time,
and awakened many people's interest in astronomy through the human
angle, as Carl did. His argument was simple, and according to Frank
Triplett goes back thousands of years: other stars are suns, our sun
has planets with people on one of them, why should not other stars also
have populated planets? But first Mitchel, like Sagan, always explained
clearly the discoveries of astronomy that fleshed out this argument with
facts. He emphasized the ``clockwork universe", governed by gravity,
that Newton, Herschel, and Laplace had investigated and found to be
stable. There were many other similarities between these two great
popularizers. Mitchel's base was the Cincinnati Observatory, which he
had founded, raising the funds for it himself in small contributions
from hundreds of ``members", which he publicised as far more democratic
than support from European kings and lords. He went abroad to get a
telescope, and finally found his ``Great [12-inch] Refractor" in Munich,
with help from John Quincy Adams, Astronomer Royal George Biddle Airy,
and Paris Observatory Director Fracois Arago, in spite of a rebuff
by President John Tyler. These episodes have similarities in Sagan's
lobbying NASA for close-up images of Mars. Views of other American
professional astronomers on life on other worlds will also be described
briefly, from Denison Olmsted, Elias Loomis, Charles A. Young (who
injected physics into the discussion), and Simon Newcomb (who had an
early, two-factor form of the ``Drake equation", and who thought planets
had been discovered in extra-solar systems), to W. W. Campbell and
H. D. Curtis (who published a quantitative estimate of the minimum-mass
planet that could be detected with their radial-velocity spectrograph).
Title: High-Resolution 3800-9500 A Light Pollution Spectra Measured
from Mt. Hamilton over San Jose, CA
Authors: Slanger, T. G.; Cosby, P. C.; Huestis, D. L.; Osterbrock,
D. E.; Stone, R. P. S.; Misch, A. A.
Bibcode: 2002AAS...201.7606S
Altcode: 2002BAAS...34R1226S
We report high-resolution (R ~ 40,000) spectra taken from Mt. Hamilton
over the city of San Jose with the Hamilton Echelle Spectrometer on
the Shane 3-m telescope. Apart from the strong atomic oxygen and
molecular OH nightglow emissions, we find a rich array of atomic
lines originating from city lighting. As expected, the strongest
lines are from sodium and mercury, but we have identified more than
150 lines from Ne, Ar, Sc, Sc+, Th, Th+, K,
Li, and Al. Fully half the lines are from scandium, an additive to
certain commercial metal halide lamps [1]. These lamps operate at
several atmospheres pressure. Correspondingly, the neutral scandium
lines are broadened and generally red-shifted, although these effects
are not observed for the Sc+ lines. Most of the scandium
emission is associated with emitting levels below 4.5 eV. Additional
telescope pointing directions were investigated, at the zenith and away
from San Jose. We report qualitative intensities for all lines. [1]
J. F. Waymouth, IEEE Transactions on Plasma Science, 19, 1003-1012
(1991).
Title: Walter Baade: A Life in Astrophysics
Authors: Osterbrock, Donald E.; Hetherington, Norriss S.
Bibcode: 2002PhT....55k..69O
Altcode:
No abstract at ADS
Title: Walter Baade, Dynamical Astronomer at Goettingen, Hamburg,
Mount Wilson, and Palomar Observatories
Authors: Osterbrock, D. E.
Bibcode: 2002DDA....33.1003O
Altcode: 2002BAAS...34..940O
Walter Baade, famous for his astrophysical discoveries, also made
many contributions in dynamical astronomy. His thesis at Goettingen
University on the spectroscopic orbit of β Lyrae was based on
spectrograms his teacher, Johannes Hartmann, had taken at Potsdam years
earlier. Immediately on receiving his Ph.D. in 1919, Baade joined the
Hamburg Bergedorf Observatory staff, and soon was the sole observer with
its 1-m reflector, the largest telescope in Europe. Under its director,
Richard Schorr, Baade's main job at first was to obtain direct plates
of asteroids and comets for positional measurements. As an incidental
part of this observing he discovered many asteroids, eight of which
were eventually named, including 966 Muschi (his wife's nickname),
944 Hidalgo, with large orbital semi-major axis, eccentricity, and
inclination, and 1036 Ganymed, whose orbit extends inside that of
Mars. Baade also discovered a new comet, 1922 II. During the close
approach of Eros in 1930 Baade measured its period of light variation,
its color, and its mean magnitude. After Pluto was discovered in
1930 he measured its position assiduously, following it as far from
opposition as he could. In 1931 Baade moved to Mount Wilson, where
he concentrated almost entirely on globular-cluster, supernova, and
galaxy research. He saw many asteroid trails on his long exposures
but did not report them except for one, 7448 (still not named), which
showed a very long trail on a 3-hr exposure of the Crab nebula. At
Palomar, using the 48-in Schmidt soon after it went into operation,
he dicovered and reported 1566 Icarus, with a very small perihelion
distance, and later his second comet, 1955 VI.
Title: James E. Keeler: Pioneer American Astrophysicist
Authors: Osterbrock, Donald E.
Bibcode: 2002jekp.book.....O
Altcode:
Preface; 1. A raw country boy from Florida; 2. I shall be glad to
keep him here for the present; 3. I could not ask for anything better;
4. Steady growth and excellent achievement; 5. A human being first and
an astronomer afterwards; 6. The ablest spectroscopist in this country;
7. I have really counted more on you than on all the others together;
8. The best man for the place; 9. An ideal director and investigator;
10. The quality of his voice still rings in my ears; References;
Bibliography; Index.
Title: A historian of Victorian astronomy
Authors: Osterbrock, Donald E.
Bibcode: 2002Natur.418..482O
Altcode:
No abstract at ADS
Title: Young Don Menzel's amazing adventures at Lick Observatory
Authors: Osterbrock, Donald E.
Bibcode: 2002JHA....33...95O
Altcode:
No abstract at ADS
Title: Pioneer Nebular Theorists from Zanstra to Seaton: and Beyond
Authors: Osterbrock, D. E.
Bibcode: 2002RMxAC..12....1O
Altcode:
A brief history of theoretical nebular astrophysics, particularly
in USA, is presented. The importance of observational knowledge
of objects that actually exist is emphasized as a prerequisite
for most theories. Herman Zanstra and Ira Bowen were the two most
important theorists in opening the field. Donald Menzel and his
students, especially James Baker, Leo Goldberg, and Lawrence Aller,
were quite important in the further development of it. Henry Norris
Russell started nebular astrophysics rolling, and several other later
theorists, including Bengt Strömgren, Lyman Spitzer, Iosif Shklovsky
and Michael Seaton, also made important contributions to it.
Title: Book Review: Walter Baade - A Life in Astrophysics (Osterbrock)
Authors: Duerbeck, Hilmar W.; Osterbrock, Donald E.
Bibcode: 2002AcHA...15..248D
Altcode:
No abstract at ADS
Title: The view from the observatory: history is too important to
be left to the historians
Authors: Osterbrock, Donald E.
Bibcode: 2002ASSL..280..201O
Altcode: 2002osa3.book..201O
A research astronomer and historian of astronomy begins this paper
with a statement on his views of the latter subject. It helps
anyone who wishes to understand its history to know and understand
astronomy. History must be based on facts, which archives, scientific
papers, and books can provide. Immersion in a field like astronomy makes
one better qualified to understand what others have done in that field,
and to write about it, as Henrik Ibsen, Ernest Hemingway, Barbara
Tuchman, and John Grisham have all stated and proved by example. The
second part of the paper is a progress report on the author's current
project, the life and scientific career of the early American astronomer
and solar physicist Charles A. Young (1834-1908). Astronomy was very
different in his "small-telescope era", but there are many modern
resonances in his problems and their solutions.
Title: Book Review: Walter Baade -- A life in Astrophysics
(D.E. Osterbrock)
Authors: Duerbeck, H. W.; Osterbrock, D. E.
Bibcode: 2001JAD.....7....9D
Altcode:
No abstract at ADS
Title: Who Really Coined the Word Supernova? Who First Predicted
Neutron Stars?
Authors: Osterbrock, D. E.
Bibcode: 2001AAS...199.1501O
Altcode: 2001BAAS...33.1330O
The answer to both questions is Walter Baade and Fritz Zwicky. They
used the word and postulated that the remnants could be neutron stars
in the abstract of their joint paper ``Supernovae and Cosmic Rays,"
presented orally by Zwicky at an American Physical Society meeting at
Stanford in December 1933. The abstract was published in the Physical
Review in early 1934, and was a condensation of their two joint papers
in PNAS in 1934. The concept that there is a special class of ``much
more luminous novae" (Lundmark 1923), which we today call supernovae,
was put forward by Knut Lundmark (1920), who called them ``giant novae,"
and independently by Heber D. Curtis (1921). Hubble (1929) referred to
them as ``exceptional novae," and Baade (1929), writing in German, as
``Hauptnovae" (chief novae). According to a review article by Zwicky
(1940), he and Baade introduced the term supernovae in seminars and an
astrophysics course at Caltech in 1931. Lundmark (1933) actually first
published the word (as ``super-Novae") in a paper dated December 31,
1932 but published in 1933. He was at Lick and Mount Wilson during
the fall and winter of 1932-33, and it is much more probable that
he heard it there than that he coined it himself. In their abstract
and PNAS papers Baade and Zwicky ``advanced the view" that supernovae
represent the collapse of ``ordinary stars into neutron stars," because
that gave about the right total energy released in the outburst. Many
physicists believe that Lev Landau (1932) had introduced this concept,
but actually his paper is about relativistically degenerate stars and
does not mention neutrons, neutron stars, nor a density. Freeman Dyson
(1971) in his published lectures on neutron stars and pulsars correctly
credited the concept to Baade and Zwicky (1934). Extracts from these
and other related papers will be posted.
Title: The View from the Observatory: History is Too Important to
be Left to the Historians
Authors: Osterbrock, D. E.
Bibcode: 2001AAS...199.3101O
Altcode: 2001BAAS...33.1354O
As the first astronomer turned historian of astronomy relatively late
in life to receive the LeRoy Doggett Prize, I am especially grateful to
its Committee for this high honor. I knew LeRoy well and worked with
him when he was Secretary`Treasurer of the HAD before his untimely
death. I will begin my lecture by paying tribute to my mentors who
encouraged and helped me to become a historian of astronomy, Mary Lea
Heger Shane, Owen Gingerich, Helen Wright, and William G. Hoyt. Then
I will speak briefly on why I think astronomers are interested in the
history of their science, buttressed by quotations from Ecclesiasticus,
Henry Ford, Thucydides, and Herodotus. Basically it is because we are
interested in our roots, just as members of a family are interested
in its roots. I will talk briefly about the Mary Lea Shane Archives
of the Lick Observatory, and what a resource it is for my specialty,
American Astronomy in the Big-Telescope Era. Its Curator, Dorothy
Schaumberg, has helped me and hundreds of other historians of astronomy
tremendously. I believe it helps anyone who wants to understand the
history of astronomy to know and understand astronomy. History must
be based on facts, which archives, scientific papers, and books can
provide. Immersion in a field like astronomy makes one better qualified
to understand what others have done in that field, and how they did it,
as Ibsen, Hemingway, Tuchman, and Grisham have all stated and proved by
example. Finally I will give a progress report on my current project,
the life and scientific career of the early American astronomer and
solar physicist Charles A. Young (1834-1908). Astronomy was very
different in his ``small-telescope era," but there are many modern
resonances in his problems and their solutions.
Title: Percival Lowell: The Culture and Science of a Boston Brahmin,
by David Strauss
Authors: Osterbrock, Donald E.
Bibcode: 2001S&T...102a..74O
Altcode:
No abstract at ADS
Title: Herman Zanstra, Donald H. Menzel, and the Zanstra method of
nebular astrophysics
Authors: Osterbrock, Donald E.
Bibcode: 2001JHA....32...93O
Altcode:
No abstract at ADS
Title: Astronomer for All Seasons: Heber D. Curtis
Authors: Osterbrock, Donald E.
Bibcode: 2001Mercu..30c..24O
Altcode:
Heber D. Curtis was the first to prove that there were galaxies beyond
our Milky Way.
Title: Walter Baade: Father of the Two Stellar Populations and
Pioneer Supernova Researcher
Authors: Osterbrock, D. E.
Bibcode: 2001AAS...198.0101O
Altcode: 2001BAAS...33..785O
Walter Baade was the great observational astronomer of the middle
part of the past century. He lived and worked in Pasadena, where he
``discovered" the two stellar populations and did outstanding pioneer
research on supernovae at Mount Wilson and Palomar Observatories from
1931 until 1959, when he returned to his native Germany, and died the
following year. Baade was born in a little town in northwest Germany,
and educated at Goettingen University, where he received his Ph.D. in
1919, just after the end of World War I. He got a research position
at Hamburg Observatory, and quickly jumped into globular cluster and
galactic structure work with its 40-in reflector, then the largest
telescope in Europe. Baade recognized very early the great importance
of the extremely rare ``highly luminous novae" which Heber D. Curtis
and Knut Lundmark isolated in 1919-21. In 1929 Baade called these
``Hauptnovae" the key to measuring distances of faint galaxies. We
call them supernovae today, a term he and Fritz Zwicky began using
in 1932. Similarly Baade's first inkling that there was a spherically
symmetric distribution of stars in our Galaxy, which he named Population
II in his two great 1944 papers, came when he began picking up field RR
Lyrae variables in 1926. Baade's research on the two stellar populations
and supernovae was extremely important in opening up the whole fields
of stellar and galactic evolution. His invited lectures at meetings
and symposia, and his courses as a visiting professor inspired a whole
generation of research astrophysicists. Baade's attractive personality
made it possible for him to make his great discoveries in a land in
which he was officially an enemy alien during World War II.
Title: Don Hendrix, Mount Wilson and Palomar Observatories
Authors: Osterbrock, Donald E.
Bibcode: 2001JATSo..21....2O
Altcode:
Master optician of Schmidt Cameras and large telescopes by Don Osgood
Hendrix, maker of the optics for the 60-inch and 100-inch at Mount
Wilson, 48-inch at Mount Palomar, and the 200-inch on Palomar.
Title: Walter Baade : a life in astrophysics
Authors: Osterbrock, Donald E.
Bibcode: 2001wbla.book.....O
Altcode:
Although less well known outside the field than Edwin Hubble, Walter
Baade (1893-1960) was arguably the most influential observational
astronomer of the twentieth century. Written by a fellow astronomer
deeply familiar with Baade and his work, this is the first biography
of this major figure in American astronomy. In it, Donald Osterbrock
suggests that Baade's greatest contribution to astrophysics was not,
as is often contended, his revision of Hubble's distance and age
scales for the universe. Rather, it was his discovery of two distinct
stellar populations: old and young stars. This discovery opened wide the
previously marginal fields of stellar and galactic evolution. Baade was
born, educated, and gained his early research experience in Germany. He
came to the United States in 1931 as a staff member of Mount Wilson
Observatory, which housed the world's largest telescope. There, he
pioneered research on supernovae. With the 100-inch telescope, he
studied globular clusters and the structure of the Milky Way, every
step leading him closer to the population concept he discovered during
the wartime years, when the skies of southern California were briefly
darkened. After his great discovery, Baade continued his research with
the new 200-inch telescope at Palomar. Always respected and well liked,
he became even more famous among astronomers as they shifted their
research to the fields he had opened. Publicity-shy and seemingly
unconcerned with publication, however, Baade's celebrity remained
largely within the field.
Title: Walter Baade at Palomar 1937 - 1958
Authors: Osterbrock, D. E.
Bibcode: 2000AAS...197.2304O
Altcode: 2000BAAS...32.1439O
Walter Baade discovered the two stellar populations with the 100-in
Mount Wilson reflector during World War II, but applied, tested,
and extended this concept with the 200-in Hale telescope after it
went into operation on Palomar Mountain in 1949. But he had begun
observing there with the 18-in Schmidt telescope in 1937, soon after it
was completed. Baade used panchromatic films and deep red filters in
an attempt to penetrate the heavy interstellar extinction toward the
Galactic center. The extinction was much too heavy for him to observe
the center, but he found the least obscured regions in this survey,
including "Baade's window," and several highly obscured globular
clusters. The 48-in Schmidt was completed in 1948, and Baade was one
of the very few observers allowed to use it briefly, before all the
observing time was turned over to the National Geographic-Palomar
Observatory Sky Survey. Again, he concentrated on seeking the
"clearest" regions near the Galactic center, and also obtained some
pictorial photographs of nebulae to publicize the success of the
new instrument. Especially after Edwin Hubble's first heart attack
in 1949, Baade took most of the final test exposures which Ira Bowen
used to analyze and tune up the shape of the 200-in mirror. After the
Hale telescope was in full operation, Baade had the lion's share of
observing time with it. He had been aching to use it to search for
RR Lyrae variables in M 31 it, and not finding any confirmed Baade's
well grounded conjecture that the distance scale in use then was
wrong. His work on variable stars in M 31, on the polarization of
the continuum of the Crab nebula, and with Rudolph Minkowski on the
optical identification of radio sources are a few examples of what
he did with it. These and several other programs will be described,
along with some of Baade's other activities at Palomar.
Title: Li I, K I, Sc I, and Other Atomic Lines in the Light-Pollution
Spectrum of San Jose, CA
Authors: Osterbrock, D. E.; Stone, R. P. S.; Misch, A. A.
Bibcode: 2000AAS...19711504O
Altcode: 2000BAAS...32.1598O
High-resolution spectra were obtained with the Hamilton Echelle
Spectrograph and the Coude Auxiliary Telescope (24-in diameter) of Lick
Observatory, to check the tentative identification by Osterbrock and
Martel (1992) of Li I λ 6708 in the night sky above San Jose. Spectra
were taken with the CAT throughout one night in fall 1999, in successive
exposures pointing low in the west over San Jose, at the zenith, and
low in the east, 45 min each. The co-added west spectrum had 3 hr total
exposure, the other two 2.25 hr each. They show conclusively that the
line arises in San Jose, and the measured wavelength, λ 6708.88,
is in good agreement with the average λ 6707.81 or the weighted
average λ 6707.84 of the Li I doublet. This feature is not present
in sky spectra taken at Mauna Kea with HIRES on the Keck I telescope,
and clearly results from light pollution. The blend is noticeably
broadened, presumably by pressure broadening, with FWHM 1 Å and FW0I 3
Å. As is well known, very strong Hg I and Na I, greatly broadened and
with strong narrow cores, from high- and low-pressure sodium lamps,
are present. The lithium is no doubt an impurity in them. Several
other weaker Na I lines have been measured and identified as well. K
I λ 7699 is present in the San Jose sky spectrum, no doubt also an
impurity in the sodium lamps. The other component of this doublet is
known to be absorbed by atmospheric O2. In addition, many
strong lines of Sc I have been identified, clearly from metal halide
lamps, some of which contain scandium. Many lines of Ne I have also
been measured and identified, probably from signs in San Jose.
Title: Accurate atomic line wavelengths from astronomical sky spectra
Authors: Slanger, T. G.; Huestis, D. L.; Cosby, P. C.; Osterbrock,
D. E.
Bibcode: 2000JChPh.113.8514S
Altcode:
Numerous atomic lines appearing in the terrestrial nightglow can be
measured by HIRES, the echelle spectrometer on the 10 meter Keck
I telescope on Mauna Kea. The observable nightglow lines include
emissions from Na, K, Hg, Ne, N, O, and H. Agreement between the line
positions and those from National Institute of Science and Technology
(NIST) compilations is excellent for well-known lines, typically
2 mÅ or better. For lines which are not well-known, or cannot be
measured directly in the laboratory, deviations are significant. In
particular, for the optically forbidden N(2D-4S)
transition the differences are substantial, 20 and 24 mÅ for the
two components. Apart from improving the line positions for this
transition, we also correct an error that has been perpetuated in the
aeronomic literature for the last 30 years concerning the transition
wavelengths. The potassium D1 line, recently discovered
in the HIRES sky spectra, exhibits a position difference of 11
mÅ between the NIST and HIRES values, significant for astronomical
applications. The HIRES value is shown to be in close agreement with the
latest laboratory study. For the Balmer series of H lines, we report the
first ground-based observation of Hγ in the geocorona, and we confirm
that the positions of the H(α,β,γ) lines agree with the expectation
that the principal source is direct solar resonance excitation, with a
5%-6% cascading contribution in the case of Hα. The absolute average
intensities of the three lines are 3600, 900, and ~210 millirayleighs
(mR), respectively.
Title: A View of the Future as Seen from the Past
Authors: Osterbrock, Donald E.
Bibcode: 2000PASP..112..869O
Altcode:
This Essay is one of a series of invited contributions which will
appear in the PASP throughout the year 200 to mark athe upcoming
millennium. (Eds.)
Title: Robert G. Aitken and His ADS: Double Star Oberver, Cataloguer,
Statistician, and Observatory Director
Authors: Osterbrock, D. E.
Bibcode: 2000DDA....31.1205O
Altcode: 2000BAAS...32..868O
Robert G. Aitken was a dynamical astronomer of the old school, a
long-time visual double star observer. He was born in 1864 in Jackson,
California, a small town in the Gold Country midway between Yosemite
and Sacramento. His education at Williams College under Truman Safford;
his early teaching career at Livermore College and the University of
the Pacific; his simultaneous graduate reading course in mathematics;
and his becoming a professional astronomer under the tutelage of
Edward S. Holden and Edward E. Barnard at Lick Observatory will be
described. Aitken made a systematic survey of the entire sky north
of -30 degrees for double stars, joined by William J. Hussey for a
time. It produced important new information on binary and multiple
stars and their orbits. His book The Binary Stars and his New
General Catalogue of Double Stars (ADS) were his monuments. Aitken
was associate director of Lick Observatory from 1923 until 1930,
while W. W. Campbell was simultaneously director and president of the
University of California. Then Aitken was director himself from 1930
until he retired in 1935 and moved to Berkeley, where he continued
writing until his death in 1951. Aitken was editor of the PASP for 51
years. He hoped that Gerard P. Kuiper would succeed him as the double
star observer at Lick Observatory, but that was not to be. Aitken at
various times held every office in the ASP, and was vice president,
then president, of the AAS.
Title: Hale's "Little Elf": The Mental Breakdowns of George Ellery
Hale
Authors: Sheehan, William; Osterbrock, Donald E.
Bibcode: 2000JHA....31...93S
Altcode:
No abstract at ADS
Title: Faint Emission Lines in the Blue and Red Spectral Regions of
the Night Airglow
Authors: Osterbrock, Donald E.; Waters, Richard T.; Barlow, Thomas A.;
Slanger, Tom G.; Cosby, Philip C.
Bibcode: 2000PASP..112..733O
Altcode:
Co-added night-sky spectra, obtained as by-products of exposures with
the Keck I 10 m telescope on Mauna Kea and the HIRES high-resolution
echelle spectrograph over a period of approximately 4 years,
all completely independent of similar data published earlier, are
presented. The new data total over 150 hours exposure in one order
(5505-5625 Å), more than 100 hours in 16 orders, and more than 50
hours in all orders in the spectral range 3923-7853 Å and include
smaller numbers of hours over the entire range 3618-9023 Å. From these
data, co-added in the red region to the previously published data,
two additional Meinel OH bands, 8-1 and 7-0, were found in emission
in the spectrum of the night airglow, the presence of the 6-0 band
was confirmed, and numerous lines of the 10-4 and 10-5 bands were
detected. Three Hg I light-pollution lines were detected as weakly
present in the Mauna Kea night sky. Three other predicted Meinel bands
are too faint and still were not detected with certainty. Similarly,
neither OD nor the Rb I or Cs I resonance lines were seen. Upper limits
were set on the latter, which are consistent with their abundance
ratios to K and the observed strength of the K I resonance line
λ7699, if the excitation mechanisms of all these three alkali atoms
were equally effective. Brief references are given to other papers in
press based on these new spectral data and to other work in progress on
identifications of many additional O2 bands in the spectrum
of the night airglow. A table summarizes all the identifications of all
OH emission bands in the spectrum of the night airglow, in all spectral
regions. Lick Observatory Bulletin 1391. Based on observations obtained
at the W. M. Keck Observatory, which is operated by the California
Institute of Technology and the University of California.
Title: Die Anfänge der Astronomie in Chile.
Authors: Duerbeck, H. W.; Osterbrock, D. E.
Bibcode: 2000S&W....39..224D
Altcode:
No abstract at ADS
Title: Obituary: Kandarpa Narahari Rao, 1921-2000
Authors: Osterbrock, Donald E.
Bibcode: 2000BAAS...32.1684O
Altcode:
No abstract at ADS
Title: A Fortunate Life in Astronomy
Authors: Osterbrock, Donald E.
Bibcode: 2000ARA&A..38....1O
Altcode:
I have had a very fortunate career in astronomy, benefiting greatly
from numerous accidents of fate. I grew up in Cincinnati, Ohio, served
in the US Army Air Force in World War II, and had all my further
education at the University of Chicago, from PhB in the College to
PhD in astronomy and astrophysics. There, as a postdoc at Princeton
University, and as a young faculty member at Caltech and Mount Wilson
and Palomar Observatories, I had excellent teachers and mentors. I have
done research primarily on gaseous nebulae and active galactic nuclei,
but also made a few early contributions on stellar interiors and the
heating in the outer layers of the Sun. The major part of my scientific
career was at the University of Wisconsin and Lick Observatory, but
I also had three productive years at the Institute for Advanced Study.
Title: VizieR Online Data Catalog: Keck/HIRES Sky Line Atlas
(Osterbrock+ 1997)
Authors: Osterbrock, D. E.; Fulbright, J. P.; Martel, A. R.; Keane,
M. J.; Trager, S. C.; Basri, G.
Bibcode: 2000yCat.3211....0O
Altcode:
This catalog provides a list of atmospheric OH and O2 lines that are
useful for wavelength calibration of high resolution spectra. Tables
of observed OH lines, and calculated wavelengths for molecular oxygen
(O2) are given; the journal of the observations is found in the "Tables
1" section below, and spectra with identified lines are provided as
postscript figures, which are summarized in the "figs.dat" file. (3
data files).
Title: Investigations of potassium, lithium, and sodium emission in
the nightglow and OH cross calibration
Authors: Slanger, T. G.; Osterbrock, D. E.
Bibcode: 2000JGR...105.1425S
Altcode:
Sky spectra from the high-resolution echelle spectrometer (HIRES)
on the Keck I telescope have been analyzed to obtain information
on the potassium, lithium, and sodium resonance line emission in the
nightglow. Relative intensity calibration is carried out against OH band
intensities, and absolute values are obtained by utilizing new averaged
intensities of the OH 9-4 band. The D1 line of potassium,
at 7699 Å, is shown to be present, as previously speculated by Swider
[1987]. Its average intensity is 1.0 R, twice as large as predicted. Any
lithium line emission at the resonance wavelengths near 6708 Å is
obscured by the PP(3) line of the 12-9 emission band of the
O2(b1Σg+-X3Σg-)
Atmospheric Band system. However, as that line has an intensity of
~60 mR, our estimated upper limit on the Li line intensities is ~15
mR. The intensity that we extract for the Na(D1) line,
averaged over 4 years, is 20 R. Although there is no solar scattering
contribution to the Na and K data, the NaD2/D1
line intensity ratio is substantially smaller than reported earlier
for nightglow conditions. Observing that the Na/KD1 line
intensity ratio is an order of magnitude smaller than the typical
[Na]/[K] concentration ratio leads to the conclusion that the maximum
efficiency for production of mesospheric Na(2P) is 0.1.
Title: Obituary: Dorothy N. Davis Locanthi, 1913-1999
Authors: Osterbrock, Donald E.
Bibcode: 2000BAAS...32.1677O
Altcode:
No abstract at ADS
Title: Walter Baade, Fritz Zwicky, and Rudolph Minkowski's Early
Supernova Research, 1927 - 1973
Authors: Osterbrock, D. E.
Bibcode: 1999AAS...19513007O
Altcode: 1999BAAS...31.1561O
Long before he ``discovered" the two stellar populations, Walter Baade
was a pioneer in research on supernovae and their remnants. In 1927,
while still in Germany, Baade emphasized what he called ``Hauptnovae"
(chief novae) as highly luminous, potential distance indicators. He
joined the Mount Wilson staff in 1931, bringing the ``secret" of
the Schmidt camera with him, and encouraged Fritz Zwicky to carry
out a supernova search with one at Palomar. Baade and Zwicky used
the term ``supernova" in their 1933 joint paper. Zwicky began a
systematic search in 1936, and Baade followed up with the 100-in
reflector to derive light curves. He confirmed that Tycho's ``nova"
of 1572 and the Crab nebula had been supernovae in our Galaxy. Baade
advised N. U. Mayall, at Lick, on his spectroscopic study of the
Crab nebula. In 1933, after Hitler came to power, Rudolph Minkowski
had to leave Germany. Baade managed to get him a Mount Wilson staff
position. Minkowski then did the spectroscopic observations of
supernovae, beginning in 1937. Within a few years he and Baade were
able to distinguish type I and II supernovae. Baade's further work on
supernovae included historical research in Latin, Italian, and German,
as well as filter photography. He searched hard for a remnant of SN 1885
in M 31, but never succeeded in finding it. After World War II the Crab
nebula was found to be a strong radio source, and Baade and Minkowski
used the 200-in to identify other supernova remnants, beginning with
Cas A. Baade collaborated closely with Jan Oort and his student, Lo
Woltjer, in their studies of the Crab nebula. After Baade retired in
1958, Minkowski continued supernova research for more than a decade;
one of his favorite objects was the expanding Cygnus Loop.
Title: Seyfert Galaxies
Authors: Osterbrock, Donald E.
Bibcode: 1999ApJ...525C.337O
Altcode: 1999ApJC..525..337O
No abstract at ADS
Title: Walter Baade's Discovery of the Two Stellar Populations
Authors: Osterbrock, Donald E.
Bibcode: 1999Ap&SS.267...23O
Altcode:
No abstract at ADS
Title: Atmospheric Atomic Emissions in Keck/HIRES Night Sky Spectra
Authors: Huestis, D. L.; Cosby, P. C.; Slanger, T. G.; Osterbrock,
D. E.; Waters, R.
Bibcode: 1999AAS...194.0911H
Altcode: 1999BAAS...31..839H
The unsurpassed resolution and sensitivity of the HIRES spectrograph at
the 10-m Keck I telescope creates new opportunities for investigation
of the emissions of the Earth's atmosphere, providing unanticipated
benefits from data collected incidentally by astronomers. In return,
aeronomers can assist the astronomy community in disentangling
terrestrial and extraterrestrial sources. Here we report recent analysis
of atomic emissions: H(4340, 4861, 6563), N(5198, 5200), O(5577, 6300,
6364, 7774, 8446), Na(5890, 5896), K(7699), and Hg(4047, 4358, 5461)
(all wavelengths in { Angstroms}). For the nitrogen lines the Keck/HIRES
wavelengths are the best available, and differ from published values
by 0.02 { Angstroms}. The stronger emissions are well known, with
intensities that typically range from about 1 R (Rayleigh) for N,
to 2 R for H(6563), 60 R for Na, 100 R for O(6300, 6364), and 200 R
for O(5577). The weaker lines are still conspicuous in the Keck/HIRES
spectra: H(4340) about 50 mR, O(8446) 150 mR, Hg 200 mR, H(4861) 250
mR, O(7774) 350 mR, and K 1.5 R. Previous aeronomy studies suggest
production mechanisms, characteristic altitudes, and time-of-night
dependences for the atomic emissions. Some, e.g. O(5577), Na, and K,
are produced by chemical processes near the mesopause (95 km) that are
relatively constant during the night. Others, N, O(6300, 6364, 7774,
8446), are produced by electron-ion recombination in the ionosphere
(120-400 km), with intensities that decrease rapidly after twilight. The
hydrogen emissions are attributed to solar-excited fluorescence in
the geocorona. The mercury emissions are probably scattered city
light. Supported by NSF Astronomy and Aeronomy and NASA Sun-Earth
Connection. The W. M. Keck Observatory is operated by the California
Institute of Technology and the University of California.
Title: George Ellery Hale's Early Solar Research at Chicago, Kenwood,
Harvard, and Yerkes Observatories, 1882-1904
Authors: Osterbrock, D. E.
Bibcode: 1999AAS...194.5701O
Altcode: 1999BAAS...31..914O
Growing up in Chicago, George Ellery Hale, later the prime spirit
in founding the AAS, was a precocious boy scientist. He was deeply
interested in spectroscopy and astrophysics from an early age. His
wealthy parents encouraged Hale's aspirations with magazines, books,
and instruments, and he acquired his first telescope when he was 14. He
knew as mentors classical astronomers S. W. Burnham and George W. Hough,
but he preferred astrophysics and designed his own Kenwood Physical
Obseervatory around a grating in a Rowland circle mounting, fed by a
heliostat, both built for him by instrument-maker John A. Brashear. For
his undergraduate thesis at MIT, Hale invented and (at Harvard
College Observatory) demonstrated the spectroheliograph. With it,
and a high-quality 12-in refractor at his later Kenwood Astrophysical
Observatory (at the same site, the Hale family home, 4 miles from the
present Hilton Hotel where the SPD, HAD and AAS are meeting) Hale did
excellent solar research, especially on promineneces, flocculi, and
the near-ultraviolet spectrum of the chromosphere. As a teen-ager and
a young adult Hale traveled widely, and met several important piuoneer
solar physicists, including Charles A. Young, Jules Janssen, Samuel
P. Langley, and Henry Rowland. Hale designed Yerkes Observatory for
solar and stellar research, and headed the solar work himself. One
of his aims always was to compare other stars with the sun. Hale's
telescopes, instruments, methods, and resulting papers will be described
and illustrated by numerous slides.
Title: The AAS ``Semi-centennial" Meeting: Northwestern University
and Yerkes Observatory, September 1947
Authors: Osterbrock, D. E.
Bibcode: 1999AAS...194.2504O
Altcode: 1999BAAS...31..863O
The AAS celebrated its "semi-centennial" fifty-two years ago! It
was actually the fiftieth anniversary of the "First Conference"
of astronomers and astrophysicists held at the dedication of Yerkes
Observatory in 1897, which led to the actual formation of the Society
two years later. Otto Struve, president of the AAS, was publicizing the
fiftieth anniversary of his Yerkes Observatory in 1947, and he simply
announced it was also the semi-centennial of the Society. Joel Stebbins,
the grand old man of the AAS who had joined it as a graduate student
in 1900, and held nearly every office in the Society from councilor
to president, supported Struve's early celebration of the anniversary,
probably largely because he was to retire himself in 1948. The meeting
was held at Northwestern University and at Yerkes. There were then
625 AAS members. About 140 of them attended the meeting, and presented
some 50 papers, all oral, with no parallel sessions. Struve organized a
symposium on stellar atmospheres, with 5 invited speakers, and the great
majority of the contributed papers were also on stars, a few on nebulae
and interstellar matter, one on galaxies, and none on cosmology. Not
to be outdone, Gerard P. Kuiper, who had recently succeeded Struve as
director of Yerkes Observatory, organized a second symposium on the
atmospheres of the planets, held at Yerkes immediately after the AAS
meeting. After two days of sessions at Evanston, the members had driven
to Williams Bay for the closing session Saturday, at which Struve and
Stebbins gave their versions of the history of the observatory and of
the Society. The two symposia formed the bases for two important books,
Astrophysics: A Topical Symposium, and The Atmospheres of the Earth
and the Planets, edited by J. Allen Hynek and Kuiper respectively.
Title: My First AAS Meeting: Bloomington and ANN Arbor, June 1950
Authors: Osterbrock, D. E.
Bibcode: 1999AAS...194.4305O
Altcode: 1999BAAS...31..883O
I attended my first AAS meeting at the end of my first year as a
graduate student at Yerkes Observatory, in the summer of 1950. Yerkes
was the home base of the astronomy faculty, staff, and graduate
students of the University of Chicago, and a large contingent went to
this meeting at nearby Indiana University, and then on to the symposium
immediately following it at the University of Michigan. In this paper
I will describe these meetings so as to bring out the differences
between this typical AAS meeting nearly half a century ago, and one
today, as well as their similarities. Briefly, the main differences
resulted from the fact that astronomy was much smaller then, and less
well funded. Membership in the AAS, attendance at its 1950 meeting, and
the number of papers presented were all smaller by factors of roughly
ten than now. Most astronomers paid their own expenses to meetings, or
were only reimbursed for part of them by their universities. Hence most
meetings were held on university campuses. There were no registration
fees, and the receptions, picnics, and outings were provided by the
``host" institution, which treated the visiting astronomers as its
guests. The AAS had no paid staff. There were no parallel sessions
nor poster papers. Members submitted only titles for their papers,
most of them on stars; fewer on planets, asteroids and meteors;
and fewer still on interstellar matter, gaseous nebulae, galaxies, or
cosmology. Research papers were the most important part of the meeting,
but ``teachers' sessions," the equivalent of the education sessions
of today, were part of the program too. Seeing old friends and meeting
new ones were an important, unscheduled part of the meeting. This paper
will provide a narrative of these meetings, illustrated by photographs
of groups, scenes, and astronomers.
Title: Halfway from La Silla to Paranal - in 1909.
Authors: Duerbeck, H. W.; Osterbrock, D. E.; Barrera S., L. H.;
Leiva G., R.
Bibcode: 1999Msngr..95...34D
Altcode:
This month - March 1999 - sees the 90th anniversary of the first
expedition in northern Chile to search for a good site for an
astronomical observatory: the Curtis expedition.
Title: The First Alvan Clark & Sons Largest Refracting Telescope
in the World
Authors: Osterbrock, Donald E.; Briggs, John W.
Bibcode: 1999JATSo..16...11O
Altcode:
A discussion of the first Alvan Clark & Sons refractor to have
the distinction of being the largest in the world.
Title: The First West Coast Meeting of the AAS
Authors: Osterbrock, Donald E.
Bibcode: 1999aasf.book...37O
Altcode:
No abstract at ADS
Title: AAS Meetings Before There Was an AAS: The Pre-History of the
Society The Pre-History of the Society
Authors: Osterbrock, Donald E.
Bibcode: 1999aasf.book....3O
Altcode:
No abstract at ADS
Title: Faint OH (nu' = 10), ^17OH, and ^18OH Emission Lines in the
Spectrum of the Night Airglow
Authors: Osterbrock, Donald E.; Fulbright, Jon P.; Cosby, Philip C.;
Barlow, Thomas A.
Bibcode: 1998PASP..110.1499O
Altcode:
We co-added night-sky spectra, recorded as by-products of exposures
with the high-resolution echelle spectrograph (HIRES) of the Keck I 10
m telescope on stars and quasars over a period of approximately 2 1/2
years, to obtain a resultant spectrum with total exposure time ranging
from 120 to 24 hr over the wavelength range 5720-8810 Å. On this very
high signal-to-noise ratio spectrum, OH emission lines from the upper
vibrational level nu^'=10, previously undetected in the night airglow,
were measured and identified. Estimates are made for the relative
population of OH (nu^'=10), and possible secondary mechanisms exciting
this level are discussed. Also, lines of the isotopic molecules ^18OH
and ^17OH were detected and measured, and the relative populations of
these heavy isotopomers are discussed. Lines of the isotopic molecule
OD were not detected, for reasons that are discussed, but predicted
wavelengths of such lines were calculated and are listed for possible
future use with even better signal-to-noise ratio spectra, preferably
at longer wavelengths. Lick Observatory Bulletin 1380.
Title: The challenges and frustrations of a veteran astronomical
optician: Robert Lundin, 1880-1962
Authors: Briggs, John W.; Osterbrock, Donald E.
Bibcode: 1998JAHH....1...93B
Altcode:
Robert Lundin, apprenticed in nineteenth century optical craftsmanship
but employed in twenty century fabrication and engineering, suffered
many frustrations during a nonetheless productive career. Son of Carl
A.R. Lundin, a senior optician at the famous American firm of Alvan
Clark & Sons, Robert grew up building telescopes. As a teenager, he
assisted with projects including the 1-m [40-inch] objective for Yerkes
Observatory. After his father's death in 1915, he became manager of
the Clark Corporation and was responsible for many smaller, successful
refractors and reflectors. Lundin also completed major projects,
including a highly praised 50.8-cm achromat for Van Vleck Observatory,
as well as a successful 33-cm astrograph used at Lowell to discover
Pluto. In 1929, a dispute with the owners of the Clark Corporation
led to Lundin's resignation and his creation of a new business,
"C.A. Robert Lundin and Associates." This short-lived firm built
several observatory refractors, including a 26.7 cm for E.W. Rice, the
retired chairman of General Electric. But none was entirely successful,
and the Great Depression finished off the company. In 1933, Lundin
took a job as head of Warner & Swasey's new optical shop, only
to experience his greatest disasters. The 2.08-m [82-inch] reflector
for McDonald Observatory was delayed for years until astronomers
uncovered an error in Lundin's procedure for testing the primary
mirror. A 38.1-cm photographic lens for the Naval Observatory was a
complete failure. Under pressure to complete a 61-cm Schmidt camera,
Lundin seems to have attempted to deceive visiting astronomers. After
retirement in the mid 1940s, Lundin moved to Austin, Texas, the home
of his daughter, where he died. His difficulties should not obscure
his success with many instruments that continue to serve as important
research and education tools.
Title: Walter Baade, observational astrophysicist, (3): Palomar and
Göttingen 1948 - 1960 (Part B).
Authors: Osterbrock, D. E.
Bibcode: 1998JHA....29..345O
Altcode:
No abstract at ADS
Title: O_2(b^1Σ_g^+), O(^1D), and O_2^+ + e Recombination in the
Lower Thermosphere
Authors: Huestis, D. L.; Slanger, T. G.; Fulbright, J. P.; Osterbrock,
D. E.
Bibcode: 1998APS..GEC.DM308H
Altcode:
Night-sky spectra taken with the HIRES spectrometer at the Keck I
telescope on Mauna Kea have revealed emissions from O_2(b^1Σ_g^+)
in vibrational levels up to v^'=15. Previously only v^'=0 was
known in the nightglow. Emissions from v^'=1 are unexpectedly
strong, comparable to v^'=2, and variable from scan to scan. v^'=1
emissions are visible up to J^'=50 (requiring a temperature of more
than 500 K, such as in the thermosphere), while v^'=2 emissions are
restricted to J^'<25 (consistent with a temperature of 200 K near
the mesopause, where O + O recombination would peak). Considering
that quenching of v^'=1 is about ten times faster than v^'=2, we
infer that separate mechanisms are responsible for production of
v^'=1 and the other vibrational levels. The principal source of
v^'=1 appears to be O_2^+ + e arrow O(^1D), followed by O(^1D) +
O2 arrow O_2(b^1Σ_g^+)_v^'=1. At twilight, this process
should have a maximum emission yield below 150 km, rising to about
250 km as the night progresses. Simultaneous observation of O(^1D)
and O_2(b^1Σ_g^+)_v^'=0,1,2 should provide new information about
kinetics in the thermosphere.
Title: Heber D. Curtis: The Re-entry Graduate Student at UVa Who
Became an Outstanding Dynamical Astronomer
Authors: Osterbrock, D. E.
Bibcode: 1998DDA....29.0303O
Altcode: 1998BAAS...30.1141O
Heber D. Curtis, the great pioneer of nebular and galactic research,
later observatory director at Allegheny and then at the University
of Michigan, was a dynamical astronomer in the earliest days of
photographic radial-velocity measurements. He did his undergraduate
work in classical languages at Michigan, where as a student he showed no
apparent interest in astronomy. Curtis's first jobs were teaching Latin
and Greek at Napa College, then at the College of the Pacific. Both
had small Clark refractors and he began observing, then measuring,
visual double stars. He decided to become an astronomer, and spent the
summers of 1897 and 1898 as a special student at Lick Observatory, and
of 1899 at Ann Arbor. In 1900, at the age of 28, married and with two
small children, Curtis entered the University of Virginia as a full-time
graduate student. Both Yerkes and Lick Observatories had declined to
accept him. At Charlottesville Curtis did his Ph.D. thesis on the orbit
of Comet 1898 I, received his degree in 1902, and immediately joined
the Lick staff. His work on spectroscopic binaries and high-velocity
stars at Mount Hamilton and at the Lick Southern Hemisphere Observatory,
will be described in this paper. W. W. Campbell and Curtis published the
First Catalogue of Spectroscopic Binaries in 1905; it listed all 140
of these objects then known. In 1909, Curtis was recalled to Lick to
take over the Crossley reflector and thus left the field of dynamical
astronomy. At Santiago, his assistant was George F. Paddock, a UVa
M.A. in astronomy who based his Ph.D. thesis on Chile observational
data. When Ormond Stone, UVa professor of astronomy and Leander
McCormick Observatory director, retired in 1912, Curtis was the first
choice to succeed him, but declined the post to remain at Lick.
Title: The Great Spherical Aberration Fiasco of 1902 and Its
Aftermath: Testing a New Big Telescope in San Diego
Authors: Osterbrock, D. E.
Bibcode: 1998AAS...192.2004O
Altcode: 1998BAAS...30..847O
In 1901, W. W. Campbell, the new director of Lick Observatory, planned
to build a "big" (0.9-m) new reflecting telescope, to be erected
in the Southern Hemisphere. His aim was complete sky coverage for
statistical studies of stellar radial velocities. Campbell designed it
as a reflector rather than a refractor to save money; when completed it
would be the largest professional-quality silver-on-glass reflector in
the world. It would be more effective in collecting light, especially
photographic light, than any of the big refractors of that era. The
37-inch primary mirror, when delivered on Mount Hamilton, proved to be
afflicted with severe spherical aberration. Like the HST nine decades
later, it was not usable. How this happened will be described. Unlike
the HST, this "Mills reflector" was still on the ground in America. The
optics were returned to the maker, John A. Brashear, in Allegheny, Pa.,
and were refigured there. To save time, the final testing and touch-ups
of the figure, in January 1903, were moved to San Diego, the clearest
accessible site in the United States. The dome, mounting, and other
equipment were waiting in a warehouse near the pier in San Francisco,
boxed for shipment to Chile. Campbell was badly injured during the
testing process, but his assistant, William H. Wright, completed
it. James McDowell of the Brashear firm did the final figuring at San
Diego, and in February 1903, Wright and Harold K. Palmer (who passed
his final Ph.D. oral exam the afternoon before their ship sailed)
took the telescope to Santiago and put it into operation there. It
proved higly successful for a quarter of a century, in obtaining the
observational data for which it was designed.
Title: High-Resolution Study of New Terrestrial Nightglow Features -
Beyond OH
Authors: Slanger, T. G.; Cosby, P. C.; Huestis, D. L.; Osterbrock,
D. E.; Fulbright, J. P.
Bibcode: 1998AAS...192.1306S
Altcode: 1998BAAS...30..838S
High-Resolution Study of New Terrestrial Nightglow Features - Beyond
OH T. G. Slanger, P. C. Cosby, and D. L. Huestis, Aeronomy Group,
Molecular Physics Laboratory, SRI International, Menlo Park, CA 94025
and D. E. Osterbrock and J. P. Fulbright, University of California
Observatories/Lick Observatory, University of California, Santa Cruz,
CA 95064 Sky spectra taken with the HIRES echelle spectrometer on
the Keck I telescope on Mauna Kea have led to the discovery of an
impressive array of new spectral nightglow features, belonging to
the O2(b(1) Sigma_ {g}(+) - X(3}/Sigmag({-)) )
Atmospheric Band system. The previous record for rotationally-resolved
spectroscopy in this system has long been held by Babcock and Herzberg
(1948), who detected the b(1) Sigma_ {g}(+) state up to v = 3 in solar
absorption spectra. Recently, Osterbrock et al. (1996) have published
0.2- Angstroms resolution sky spectra showing levels up to v = 4, and
these same data have been further analyzed to reveal that levels up
to v = 10 could be seen. With a more recent data set in which signals
have been accumulated for up to 120 hours, we are now able to measure
levels up to v = 15, which encompasses 3/4 of the b(1) Sigma_ {g}(+)
state potential. The discovery of these new spectral features in the
O2 terrestrial nightglow has an impact on our understanding
of other planets. The b(1) Sigma_ {g}(+) state, along with the
lower-lying a(1) Delta_ {g} state, produces emission which should
be discernible in the CO2 atmospheres of Mars and Venus,
as a result of the oxygen-atom recombination which is recognized to
be as important a process in those environments as in the terrestrial
atmosphere. The a(1) Delta_ {g} state emission, from the v = 0 level,
is a well-known though puzzling feature of the Venus atmosphere,
both on the day and night sides. From the HIRES observations, and our
laboratory program to determine the temperature-dependent effects of
atmospheric quenching of vibrationally-excited levels by O2,
N2, and CO2, we ultimately expect to be able
to predict the intensities to be found on Mars and Venus in these
O2 emission systems.
Title: George Ellery Hale, Caltech Astrophysics, and the Hale 200-inch
Telescope, 1920-1948
Authors: Osterbrock, D. E.
Bibcode: 1998AAS...192.0103O
Altcode: 1998BAAS...30..821O
Caltech and the 200-inch Hale telescope on Palomar are two of George
Ellery Hale's many creations in Southern California. He brought
the California Institute of Technology into existence in 1920;
Palomar Observatory was built for it. However, even before Hale had
"secured" the funds for the 200-inch, astrophysical research had been
underway on the Caltech campus in Pasadena, and it intensified after
the Rockefeller grant came through. Interactions between the campus,
Palomar Mountain, and Mount Wilson Obervatory (one of Hale's earlier
creations) played important roles in determining the course of Caltech
astrophysics. Changing funding patterns (from private philanthropy
to drought, then "defense" weapons-development programs, and then
governmental agencies designed to support scientific research) will
be briefly described. The 18-inch Schmidt, built at the Caltech
(200-inch Telescope) Shop, went into operation in 1936, the first
research telescope on Palomar. The 200-inch, essentially completed,
was dedicated in 1948 and went into operation for regularly scheduled
research observations near the end of 1949. Its coude spectrograph was
completed and put into regular use in stages from 1950 to 1952, Among
the most important leaders of Caltech astrophysics up to 1948 and the
years immediately after it when the 200-inch went into full operation
were Robert A. Millikan, Max Mason, and Lee A. DuBridge. Some of the
astrophysicists who worked at Caltech and Palomar were Albert Einstein,
Richard C. Tolman, Fritz Zwicky, Ira S. Bowen, John A. Anderson,
Sinclair Smith, John Strong, William A. Fowler and, just at the end
of this period, Jesse L. Greenstein. Some of the key staff personnel
were Russell W. Porter, Don O. Hendrix (on loan), and Byron Hill.
Title: Precision Wavelengths for Expected Emission Lines in
High-Redshift Galaxies and Quasars
Authors: Osterbrock, D. E.
Bibcode: 1998RMxAC...7..180O
Altcode:
No abstract at ADS
Title: Obituary: Subrahmanyan Chandrasekhar : (19 October 1910 -
21 August 1995)
Authors: Osterbrock, Donald E.
Bibcode: 1998PAPhS.142..658O
Altcode:
No abstract at ADS
Title: The O2(b1 g+) State - Nightglow Observations and Laboratory
Kinetics
Authors: Slanger, T. G.; Cosby, P. C.; Huestis, D. L.; Hwang, E. S.;
Bloemink, H. I.; Copeland, R. A.; Osterbrock, D. E.
Bibcode: 1998lss..work..236S
Altcode:
No abstract at ADS
Title: Molecular Spectroscopy with the Biggest Night-Sky Spectrograph
in the World
Authors: Osterbrock, D. E.; Fulbright, J. P.; Barlow, T. A.; Slanger,
T. G.; Huestis, D. L.; Cosby, P. C.
Bibcode: 1997AAS...191.4111O
Altcode: 1997BAAS...29.1271O
The emission lines of the night sky, recorded on every astronomical
spectrogram, are in many ways a nuisance to observers, but they also
provide a highly accurate standard wavelength reference system. There
are OH Meinel main-band lines with wavelengths known to 0.00001
Angstroms in every echelle order from lambda5800 to lambda10600 . the
present practical CCD limit. In addition, using coadded spectra
from many observers taken with HIRES on the Keck I telescope, we
have constructed a night-sky spectrum averaging 100 hours exposure
from lambda5770 to lambda7075 , decreasing gradually to 30 hours
at lambda8000 . On it and similar, earlier, shorter-exposure summed
spectra many satellite lines of OH have been identified, also many
isotopic main-band lines of (18) OH, and also four main-band lines
from the previously unobserved (in the night sky) level v' = 10. Also,
many previously unobserved O_2 atmospheric bands have been detected and
identified, to higher vibrational energy levels than measured in the
laboratory, and the complicated interplay of absorption and emission
in the (16) O(16) O (with alternate rotational levels nonexistent),
(16) O(17) O and (16) O(18) O bands have been studied.
Title: Now we are ten: the AAS tenth, decennial meeting at Yerkes
Observatory in August 1909.
Authors: Osterbrock, D. E.
Bibcode: 1997BAAS...29.1255O
Altcode:
No abstract at ADS
Title: Now We Are Ten: The AAS Tenth, Decennial Meeting at Yerkes
Observatory in August 1909
Authors: Osterbrock, D. E.
Bibcode: 1997AAS...191.2803O
Altcode: 1997BAAS...29Q1256O
The tenth meeting of the Astronomical and Astrophysical Society of
America (later to become the AAS), held in August 1909, was also its
tenth-anniversary (or decennial) meeting. Fifty-three members were
present, as contrasted with the 1400 expected for the 194th, Centennial
meeting to be held in Chicago in May-June 1999, and forty-one papers
were presented, rather than the 1000 predicted for next year. Other
similarities and differences between meetings then and now will be
described and illustrated. Simon Newcomb, the first AAS President,
had died in July 1909, and Edward C. Pickering, who had succeeded him
in 1905 and was to remain President until 1919, eulogized him at the
Yerkes meeting. Two Committees, on Luminous Meteors and on Comets,
respectively, presented their reports, the latter's dealing mostly
with plans for Comet Halley at its 1910 apparition. A high-level
Special Committee issued a statement decrying a newspaper furor
over establishing communication with Mars, which they said was then
``outside the range of contemporary science." Six of the members
present at the 1909 meeting were women. Joel Stebbins, later to be
Councilor, Secretary, Vice President and President, presented his first
AAS paper, on his new selenium (photo-resistive) photometry. Frank
Schlesinger, another future Society President, was also present
and read an instrument-design paper. Ten of the papers were given
by Yerkes and University of Chicago astronomers, including three by
E. E. Barnard and two by Kurt Laves. Another six papers from distant
Lick Observatory members were read in absentia. S. W. Burnham, who was
at the Yerkes meeting, was the one famous astronomer who never joined
the Society. Finally, the Council authorized publication of a Decennial
Book, to provide a record of the first ten years of the young Society.
Title: Walter Baade, Observational Astrophysicist, (3): Palomar and
Göttengen 1948-1969(Part A)
Authors: Osterbrock, Donald E.
Bibcode: 1997JHA....28..283O
Altcode:
No abstract at ADS
Title: The isotopic oxygen nightglow as viewed from Mauna Kea.
Authors: Slanger, T. G.; Huestis, D. L.; Osterbrock, D. E.; Fulbright,
J. P.
Bibcode: 1997Sci...277.1485S
Altcode:
Optical spectra of the terrestrial nightglow in the 520- to 900-nm
region, as measured by the W.M. Keck telescope on Mauna Kea in Hawaii
and the associated high-resolution echelle spectrograph, showed many
bands belonging to the important O2(b-X) atmospheric band
emission system. Previous ground-based measurements have shown only a
single band, from the lowest vibrational level of the emitting state. Of
particular interest is the fact that at the 762-nm position of the b-X
0-0 band, where earlier studies have shown only absorption features,
these results showed both absorption at the 16O16O
line positions and well-resolved emission at the positions of many
of the 18O16O and 17O16O
lines. These findings show that substantial advances can be made in
understanding atmospheric emission phenomena by the use of astronomical
tools.
Title: George Van Biesbroeck: Classical Dynamical Astronomer of
Binary Stars Comets, Asteroids, Planets and Satellites
Authors: Osterbrock, D. E.
Bibcode: 1997BAAS...29.1097O
Altcode:
No abstract at ADS
Title: Night-Sky High-Resolution Spectral Atlas of OH Emission Lines
for Echelle Spectrograph Wavelength Calibration. II.
Authors: Osterbrock, D. E.; Fulbright, J. P.; Bida, T. A.
Bibcode: 1997PASP..109..614O
Altcode:
The potential of night-sky emission lines recorded on every
long-exposure astronomical spectrum, for wavelength calibration, is
reemphasized. The previously published high-resolution atlas, based on
spectra obtained with the Keck 10-meter telescope on Mauna Kea and the
HIRES high-resolution echelle spectrograph, is extended from 9000 \AA
to 10600 \AA, the present effective long-wavelength limit for reasonable
exposure times with current CCD's. The extension of the atlas shows many
OH night-sky lines, and makes it possible to identify them easily on
high-resolution spectra. Accurate wavelengths and references to their
sources are given. Measured intensity ratios for the resolved, well
measured lambda-type doublets are presented, and the probable errors
in the listed wavelengths of the unresolved doublets, based on them,
are discussed. Observations and identifications of a number of lines
of weak satellite or intecombination bands of OH in the night-sky
spectrum are discussed, and the "not proven" result of a search for
OH lines in the (10 - 5) and (10 - 4) bands is mentione. (SECTION:
Atmospheric Phenomena and Seeing)
Title: The nature, structure, refuelling, and evolution of AGNs
Authors: Osterbrock, Donald E.
Bibcode: 1997ulki.book..171O
Altcode:
No abstract at ADS
Title: Yerkes Observatory, 1892-1950 : the birth, near death, and
resurrection of a scientific research institution
Authors: Osterbrock, Donald E.
Bibcode: 1997yeob.book.....O
Altcode: 1997QB82.U62W556...
No abstract at ADS
Title: Solar system astronomy in America: Communities, patronage,
and interdisciplinary science, 1920-1960, by Ronald E. Doel
Authors: Osterbrock, Donald E.
Bibcode: 1997PhT....50a..71O
Altcode:
No abstract at ADS
Title: Obituary: Louis Berman, 1903-1997
Authors: Osterbrock, Donald E.
Bibcode: 1997BAAS...29.1468O
Altcode:
No abstract at ADS
Title: Chandra and his students at Yerkes Observatory
Authors: Osterbrock, Donald E.
Bibcode: 1996JApA...17..233O
Altcode:
S. Chandrasekhar's interactions with graduate students in his more
than a quarter century at Yerkes Observatory are described. His
graduate teaching, Ph.D. thesis students, colloquia and colloquium
series, and seminar series were all important aspects of this side
of his scientific research career. His managing editorship of The
Astrophysical Journal, his one experience in observational astrophysics,
a second paper he wrote describing some of the early observational
work at Yerkes Observatory, and a third on "the case for astronomy"
are all discussed. A famous myth about one of his courses is corrected,
and the circumstances under which the "S. Candlestickmaker" parody was
written are recounted. Chandra's computers, recruited in the Williams
Bay community, are mentioned. A complete or nearly complete table of
all the thesis students who received their Ph.D. degrees under his
supervision, at Yerkes and on the campus in Chicago up through his
last one in Astronomy and Astrophysics in 1973, is presented, with
references to their published thesis papers.
Title: Walter Baade, Observational Astrophysicist, (2): Mount Wilson
1931-1947
Authors: Osterbrock, Donald E.
Bibcode: 1996JHA....27..301O
Altcode:
No abstract at ADS
Title: Obituary: Thornton L. Page, 1913-1996
Authors: Osterbrock, Donald E.
Bibcode: 1996BAAS...28.1461O
Altcode:
No abstract at ADS
Title: The Dynamical Astronomy Theorist Who Would Be Rich: Forest
Ray Moulton
Authors: Osterbrock, D. E.
Bibcode: 1996DDA....27..203O
Altcode: 1996BAAS...28.1182O
No abstract at ADS
Title: George C. Comstock: Wisconsin Astronomer, Observatory Director,
Graduate School Dean, and AAS Officer
Authors: Osterbrock, D. E.
Bibcode: 1996AAS...188.2702O
Altcode: 1996BAAS...28..859O
George C. Comstock, the third director of Washburn Observatory,
had a long and interesting career at Wisconsin. Born in Madison, he
did his undergraduate work at Michigan under James Watson. From him
Comstock learned the classical astronomy of stellar positions and
celestial mechanics. He had one year of graduate work at Michigan
before going to Madison as Watson's assistant in 1880, and remained
after the latter's death as E.S. Holden's assistant. At Wisconsin,
Comstock also studied law at the UW Law School in his ``spare time",
to have an alternate career path. He was admitted to the bar in 1883
but never practiced. From 1885-7 he was on the Ohio State faculty with
a summer working at Lick Observatory; then in 1887 became associate
director back at Washburn Observatory. Two years later he succeeded to
the full directorship, and kept the post until he retired in 1922 at
the age of 67. All Comstock's research was in positional astronomy,
and he considered his most important work to be the measurement
of stellar aberration and atmospheric refraction. He also measured
double stars with the 15-inch Washburn refractor. His main duty at
UW was teaching, mostly ``practical astronomy" for civil engineering
students. Comstock wrote several text books on astronomy, surveying,
and least squares. He was the first head of the UW Graduate School,
set up by President Charles R. Van Hise in 1904. Comstock was a highly
effective administrator, and did much to build up research at UW. His
own most successful students were Sidney D. Townley, Joel Stebbins,
and Sebastian Albrecht. Because of his legal training, Comstock was
involved as an officer in many scientific societies. He was one of
the organizers of the AAS, its first secretary, and later its vice
president, then president. He retired in 1922, and was succeeded by
Stebbins, whom he helped to bring back to Madison from Illinois. After
his retirement, Comstock lived in Beloit until his death in 1934.
Title: Night-Sky High-Resolution Spectral Atlas of OH and O2 Emission
Lines for Echelle Spectrograph Wavelength Calibration
Authors: Osterbrock, Donald E.; Fulbright, Jon P.; Martel, Andre R.;
Keane, Michael J.; Trager, Scott C.; Basri, Gibor
Bibcode: 1996PASP..108..277O
Altcode:
The potential of night-sky emission lines recorded on every
long-exposure astronomical spectrum, for wavelength calibration, is
emphasized. A high-resolution atlas, based on spectra obtained with
the Keck 10-meter telescope on Mauna Kea and the HIRES high-resolution
echelle spectrograph is presented. This atlas shows OH, O2, and a
few other night-sky lines, and will make it possible to identify them
easily on high-resolution spectra. Accurate wavelengths and references
to their sources are given. (SECTION: Atmospheric Phenomena and Seeing)
Title: Near-Infrared Emission-Line Spectrum of NGC 1068
Authors: Osterbrock, Donald E.; Fulbright, Jon P.
Bibcode: 1996PASP..108..183O
Altcode:
Relative line-flux measurements are given of the Seyfert 2,
"hidden-BLR" galaxy NGC 1068 in the near-infrared spectral region
lambda-lambda-7000 - 10830. They are corrected approximately for
extinction on a "one-layer" model, and discussed in terms of ionization
and energy-input, particularly in the high-ionization regions in which
[Fe XI] lambda-7892 and [S VIII] lambda-9913 are emitted. The need for
new calculations of collision strengths for these and other similar
ions is emphasized, based on current quantum mechanical methods using
large numbers of multiconfiguration wave functions. (SECTION: Galaxies)
Title: Young Otto Struve: The Education and Development of A Research
Scientist 1921-1932
Authors: Osterbrock, D. E.
Bibcode: 1995AAS...187.3504O
Altcode: 1995BAAS...27.1331O
Otto Struve arrived at Yerkes Observatory from Turkey in October 1921,
the penniless survivor of a defeated army. Then 24 years old, he
immediately began his studies and assistantship as the only graduate
student at the observatory. Eleven years later he became its "boy
director." His education, training, research experience and development
are described in the context of Yerkes Observatory, and of American
graduate and post-graduate work in astronomy of the time. Under Director
Edwin B. Frost, Yerkes Observatory's main program was radial-velocity
measurements of O, B, and A stars. Struve worked on it and did his
thesis on spectroscopic binaries. A prodigious achiever, he was
appointed to the faculty as an instructor as soon as he received his
doctorate. On his own he jumped into frontier research on interstellar
absorption lines, based in large part on existing spectrograms taken for
the radial-velocity program. Reviewing Cecilia Payne's book on stellar
atmospheres in 1926 converted Struve to a self-taught observational
astrophysicist. Research leaves at Mount Wilson and Harvard, with
working visits to Lick and the DAO, plus a Guggenheim year at Cambridge
with Arthur S. Eddington, broadened his horizons. Struve always observed
diligently, published frequently, attended AAS meetings, presented oral
papers, and discussed his research with others. With practically no
knowledge of modern physics, he cultivated others who were experts in
it, beginning with Pol Swings, a visitor from Belgium. By 1932 Struve
was ready to become director of Yerkes Observatory, and to lead it
back into its place as a leading astrophysical research center, for
which George Ellery Hale had founded it.
Title: Near-Infrared Emission-Line Spectrum of NGC 1068
Authors: Osterbrock, D. E.; Fulbright, J. P.
Bibcode: 1995AAS...187.5606O
Altcode: 1995BAAS...27.1367O
Relative line-flux measurements are given of the Seyfert 2, "hidden-BLR"
galaxy NGC 1068 in the near-infrared spectral region lambda lambda
7000 - 10830. They are corrected approximately for extinction in a
``one-layer'' model, and are discussed in terms of ionization and
energy-input, particularly in the high-ionization regions in which
[Fe XI] lambda7892 and [S VIII] lambda9913 are emitted. The need for
new calculations of collision strengths for these and other similar
ions is emphasized, based on current quantum-mechanical methods using
large numbers of multi-configuration wave functions.
Title: Founded in 1895 by George E. Hale and James E. Keeler: The
Astrophysical Journal Centennial
Authors: Osterbrock, D. E.
Bibcode: 1995AAS...186.1402O
Altcode: 1995BAAS...27..829O
A brief history of the Astrophysical Journal is given, concentrating on
its beginnings, its predecessor and rival journals, the astrophysicists
who founded it, and the growth and development of astrophysics in the
century since then. Later stages in the Journal's history are related,
in less detail, down to the present. Some of the first papers in new
fields, such as radio astronomy, balloon astronomy, space astronomy,
and X-ray astronomy are mentioned. A few of the financial crises
are described, as well as one or two attempts to undercut the
Journal. Slides of all the managing editors: George Ellery Hale
(1895-1904), Edwin B. Frost (1905-32), Otto Struve (1932-47), William
W. Morgan (1947-52), S. Chandrasekhar (1952-71), and Helmut A. Abt
(1971- ) will be shown. Slides of other editors, including Benjamin
A. Gould (Astronomical Journal), William W. Payne (Sidereal Messenger),
Edward S. Holden (PASP), and W. W. Campbell (Lick Observatory Bulletins)
will also be shown, and their publications discussed.
Title: Walter Baade, Observational Astrophysicist, (1): The
Preparation 1893-1931
Authors: Osterbrock, Donald E.
Bibcode: 1995JHA....26....1O
Altcode:
No abstract at ADS
Title: An infrared astronomer's early vision of airborne astronomy:
Paul Merrill 1920.
Authors: Osterbrock, Donald E.
Bibcode: 1995ASPC...73..619O
Altcode: 1995fgts.symp..619O
The first published paper by a professional, research astronomer which
discussed airborne astronomy from airplanes was by Paul W. Merrill. In
it he proposed some of the types of observations which might be made,
looking up at astronomical objects in the sky. This paper describes
Merrill's paper, his education, training and subsequent career, and
a few other aspects of the early history of airborne astronomy.
Title: Founded in 1895 by George E. Hale and James E. Keeler: The
Astrophysical Journal Centennial
Authors: Osterbrock, Donald E.
Bibcode: 1995ApJ...438....1O
Altcode:
A brief history of the Astrophysical Journal is given, concentrating
on its beginnings, its predecessor journals, the astrophysicists
who founded it, and the growth and development of astrophysics in the
century then. Latter stages in its history are related, in less detail,
down to the present.
Title: The two stellar populations.
Authors: Osterbrock, D. E.
Bibcode: 1995GriO...59f..14O
Altcode:
No abstract at ADS
Title: Walter Baade's Discovery of the Two Stellar Populations
Authors: Osterbrock, Donald E.
Bibcode: 1995IAUS..164...21O
Altcode:
No abstract at ADS
Title: Obituary: William W. Morgan, 1906-1994
Authors: Osterbrock, Donald E.
Bibcode: 1994PhT....47l..82O
Altcode:
No abstract at ADS
Title: Book-Review - Pauper and Prince - Ritchey Hale and Big
American Telescopes
Authors: Osterbrock, D. E.; Rendtel, J.
Bibcode: 1994AN....315..438O
Altcode:
No abstract at ADS
Title: Obituary: Franklin Evans Roach, 1905-1993
Authors: Osterbrock, Donald E.
Bibcode: 1994BAAS...26.1608O
Altcode:
No abstract at ADS
Title: [Fe ii] Emission from High-Density Regions in the Orion Nebula
Authors: Bautista, Manuel A.; Pradhan, Anil K.; Osterbrock, Donald E.
Bibcode: 1994ApJ...432L.135B
Altcode:
Direct spectroscopic evidence of high-density regions
in the Orion Nebula, Ne approximately equals
105-107/cu cm, is obtained from the forbidden
optical and near-IR (Fe II) emission lines, using new atomic
data. Calculations for level populations and line ratios are carried
out using 16, 35, and 142 level collisional-radiative models for
Fe II. Estimates of Fe(+) abundances derived from the near-infrared
and the optical line intensities are consistent with a high density
of 106/cu cm in the (Fe II) emitting regions. Important
consequences for abundance determinations in the nebula are pointed out.
Title: Slit Spectra of Second Byurakan Survey Galaxies
Authors: Martel, Andre; Osterbrock, Donald E.
Bibcode: 1994AJ....107.1283M
Altcode:
Slit spectra have been obtained at Lick Observatory of 18 Seyfert galaxy
candidates from the Second Byurakan Spectral Sky Survey (SBS). The great
majority of them turned out to be Seyfert galaxies. The classifications
and redshifts of all the galaxies are reported. Measurements of
the intensity ratios of the emission lines used in classifying
the galaxies are tabulated and plotted on diagnostic diagrams. The
spectra of seven of the galaxies are described in detail. In general,
our classification and redshift measurements are in very good accord
with those of Lipovetsky, Stepanian, and their collaborators at the
Special Astrophysical Observatory, showing that their results can be
used in conjunction with the Lick results with little if any systematic
differences between the two data sets. The importance of the SBS as a
source of new Seyferts bridging the gap between low-redshift Seyfert
galaxies and higher luminosity QSOs is also emphasized.
Title: Observational cosmologist
Authors: Osterbrock, Donald E.
Bibcode: 1994Natur.367..423O
Altcode: 1994Natur.367..423S
No abstract at ADS
Title: Getting the Picture: Wide-field Astronomical Photography from
Barnard to the Achromatic Schmidt 1888-1992
Authors: Osterbrock, Donald E.
Bibcode: 1994JHA....25....1O
Altcode:
No abstract at ADS
Title: Fifty Years Ago: Astronomy; Yerkes Observatory; Morgan,
Keenan, Kellman
Authors: Osterbrock, D. E.
Bibcode: 1994ASPC...60..199O
Altcode: 1994mpyp.conf..199O
No abstract at ADS
Title: Pauper & Prince: Ritchey, Hale & Big American
Telescopes
Authors: Osterbrock, Donald E.; Devorkin, David H.
Bibcode: 1994PhT....47g..68O
Altcode:
No abstract at ADS
Title: [Fe II] Emission from High Density Regions in the Orion Nebula
Authors: Bautista, Manuel A.; Pradhan, Anil K.; Osterbrock, Donald E.
Bibcode: 1994aelp.conf....1B
Altcode:
No abstract at ADS
Title: Slit Spectra of Second Byurakan Survey Galaxies
Authors: Osterbrock, D. E.; Martel, A.
Bibcode: 1993AAS...18310005O
Altcode: 1993BAAS...25.1440O
Slit spectra have been obtained at Lick Observatory of 18 Seyfert galaxy
candidates from the Second Byurakan Spectral Sky Survey (SBS). The great
majority of them turned out to be Seyfert galaxies. The classifications
and redshifts of all the galaxies are reported. Measurements of
the intensity ratios of the emission lines used in classifying
the galaxies are tabulated and plotted on diagnostic diagrams. The
spectra of seven of the galaxies are described in detail. In general,
our classification and redshift measurements are in very good accord
with those of Lipovetsky, Stepanian, and their collaborators at the
Special Astrophysical Observatory, showing that their results can be
used in conjunction with the Lick results with little if any systematic
difference between the two data sets. The importance of the SBS as a
source of new Seyferts bridging the gap between low-redshift Seyfert
galaxies and higher-luminosity QSOs is also emphasized.
Title: Walter Baade and the Southern Hemisphere
Authors: Osterbrock, D. E.
Bibcode: 1993AAS...183.3402O
Altcode: 1993BAAS...25.1343O
The inception of the European Southern Observatory is generally traced
to Walter Baade's discussions with Jan Oort during his visit to Leiden
in the spring of 1953. However, these discussions had certainly been
underway between them previously, during Oort's visit to Pasadena in
early 1952. Furthermore, Baade's great interest in southern-hemisphere
astronomy and his strong desire to observe there can be traced far back
in his career. In 1927, after his return to Germany from a year in the
U.S. under a Rockefeller fellowship, Baade reported that his country
had no chance to catch up with American astronomy in the northern
hemisphere. He advocated moving the Hamburg 1-meter reflector to the
southern hemisphere to get in ahead of the U.S. with an effective
telescope there. Baade emphasized the research that could be done on
high-luminosity and variable stars in the Magellanic Clouds. Later,
after he had joined the Mount Wilson staff, his early attempts to locate
the center of our Galaxy and globular clusters near it (in 1937) and
his observational study (with Edwin Hubble) of the Sculptor and Fornax
dwarf galaxies (in 1939) re-emphasized to him the need for a southern
observatory. During and soon after World War II he made many suggestions
on a search for ``cluster-type variables'' in the Magellanic Clouds to
Enrique Gaviola, director of the new 1.5-meter Bosque Alegre reflector
in Argentina. Baade wanted to go there to observe with it himself, but
his German citizenship prevented him from leaving the U.S.. Finally, in
the last year of his life, he was able to observe NGC 6522 (the globular
cluster in ``his'' window), with the Mount Stromlo 1.9-meter reflector.
Title: Book-Review - Pauper and Prince - Ritchey Hale and Big
American Telescopes
Authors: Osterbrock, D. E.; Marriott, R. A.
Bibcode: 1993JBAA..103Q.320O
Altcode:
No abstract at ADS
Title: The nature and structure of active galactic nuclei. II.
Authors: Osterbrock, D. E.
Bibcode: 1993RMxAA..26...65O
Altcode:
The author's current understanding of the nature and structure of
active galactic nuclei is described, chiefly on the basis on optical
spectroscopy, but including results of many authors, covering the
entire observable wavelength of energy range. The importance of dust
within the AGNs is emphasized, and current ideas of its distribution
and of its effect on the observed spectra, are discussed. The torus
model, polarization, and the "hidden Seyfert 1" nature of NGC 1068
and at least some other Seyfert 2 galaxies are discussed. It is likely
that most QSOs, Seyfert galaxies and LINERs form one family, and there
may be many as yet undetected low-luminosity AGNs in apparently normal
galaxies. A working hypothesis, involving refueling of inactive galactic
nuclei through galaxy interactions, is sketched.
Title: Books-Received - Pauper and Prince - Ritchey Hale and Big
American Telescopes
Authors: Osterbrock, D. E.
Bibcode: 1993Sci...262..775O
Altcode:
No abstract at ADS
Title: Spectroscopic Study of the CfA Sample of Seyfert Galaxies
Authors: Osterbrock, Donald E.; Martel, Andre
Bibcode: 1993ApJ...414..552O
Altcode:
High signal-to-noise ratio spectra were obtained of nearly all the
Seyfert 2 galaxies in the CfA complete sample published by Huchra &
Burg, and of some of the Seyfert 1's as well. Several of the Seyfert 2
galaxies have weak, broad components to their Hα emission lines, and
in some cases to Hβ as well, and thus are Seyfert 1.8 or 1.9 objects
on the Lick Observatory classfication system. Luminosity functions and
mean absolute magnitudes were calculated separately for each type and
for various groupings of the types. Our spectra confirm Huchra &
Burg's conclusion that the CfA sample contains a higher fraction of
Seyfert 1's than the Wasilewski sample, which therefore appears to be
deficient in faint, reddened Seyfert 1 galaxies. Specific geometrical
models and evolutionary pictures of AGNs are discussed. All the Seyfert
1.8, 1.9, and 2 galaxy spectra were measured spectrophotometrically,
and all, when plotted in diagnostic diagrams, lie in the AGN regions
except for two objects barely outside the region on one diagram. These
good signal-to-noise ratio spectra confirm that, as suspected earlier,
many Seyfert 1.8, 1.9, and 2 galaxies have weak [Fe x]λ6735 emission in
their spectra. The broad components of the Seyfert 1.8 and 1.9 galaxies
have large Hα/Hβ intensity ratios, extending previous similar results.
Title: Edwin Hubble und die Expansion des Universums.
Authors: Osterbrock, D. E.; Gwinn, J. A.; Brashear, R. S.
Bibcode: 1993SpWis...9...78O
Altcode:
No abstract at ADS
Title: Edwin Hubble and the expanding Universe.
Authors: Osterbrock, D. E.; Gwinn, J. A.; Brashear, R. S.
Bibcode: 1993SciAm.269a..70O
Altcode: 1993SciAm.269...70O
More than any other individual, Edwin Hubble shaped astronomers'
present understanding of an expanding Universe populated by a multitude
of galaxies.
Title: Edwin Hubble and the expanding universe.
Authors: Osterbrock, D. E.; Gwinn, J. A.; Brashear, R. S.
Bibcode: 1993SciAm.269a..84O
Altcode: 1993SciAm.269...84O
No abstract at ADS
Title: A Vermont Yankee in Queen Urania's Court: S. W. Burnham,
Double-Star Expert
Authors: Osterbrock, D. E.
Bibcode: 1993BAAS...25.1236O
Altcode:
No abstract at ADS
Title: Mount Hamilton's Lady Bountiful: Elizabeth Ballard Campbell
Authors: Schaumberg, D. E.; Osterbrock, D. E.
Bibcode: 1993AAS...182.8004S
Altcode: 1993BAAS...25R.932S
No abstract at ADS
Title: The Father of the Two Stellar Populations: Walter Baade,
Observational Astrophysicist
Authors: Osterbrock, D. E.
Bibcode: 1993AAS...182.8002O
Altcode: 1993BAAS...25..932O
No abstract at ADS
Title: We are Still Carrying on, Although it is Really Getting Tough:
Lick Observtory in World War II
Authors: Osterbrock, D. E.
Bibcode: 1993AAS...182.7202O
Altcode: 1993BAAS...25..922O
No abstract at ADS
Title: New Haven Observers. (Book Reviews: Astronomy at Yale,
1701-1968.)
Authors: Osterbrock, Donald E.
Bibcode: 1993Sci...260..568O
Altcode:
No abstract at ADS
Title: New Haven Observers. (Book Reviews: Astronomy at Yale,
1701-1968.)
Authors: Osterbrock, Donald E.
Bibcode: 1993Sci...260..568H
Altcode:
No abstract at ADS
Title: The Canada-France Telescope and Ritchey, George-Willis -
Great Telescopes of the Future
Authors: Osterbrock, D. E.
Bibcode: 1993JRASC..87...51O
Altcode:
No abstract at ADS
Title: The Nature and Structure of Active Galactic Nuclei
Authors: Osterbrock, Donald E.
Bibcode: 1993ApJ...404..551O
Altcode:
Current knowledge of the structure of AGNs and the physical principles
that govern them are reviewed, along with clues as to their formation
and evolution. Evidence from optical observational data is stressed, but
the importance of radio, millimeter, infrared, ultraviolet, and X-ray
results is also emphasized. Overall, AGNs form one family, but there are
many differences in detail among them. Spectral classification of AGNs
is reviewed. Diagnostic diagrams involving optical and near-infrared
emission-line ratios to separate AGNs from H II regions or starburst
galaxies are briefly discussed. Observed jets indicate that many, if
not all, AGNs have an axis, and that cylindrical rather than spherical
symmetry governs them. The central source is very probably an accretion
disk around a massive black hole, and photoionization by high-energy
photons is an important energy-input mechanism to the observed gas. The
photoionizing spectrum is a hard one, generally more complicated than
a simple power law. There is considerable evidence, especially from
spectropolarimetry, that many Seyfert 2 galaxies contain a broad-line
region, hidden within an obscuring torus, and would be observed as
Seyfert 1 galaxies from a different orientation. At high luminosities
there are essentially no Seyfert 2 galaxies, indicating that the
obscuring torus is very thin or cannot exist under these conditions,
or that the nuclear radiation is highly anisotropic. The velocity field
in AGNs includes rotation and "turbulence" (disordered motion) in the
broad-line region. There may also be inflow and outflow (or both, in
different parts of the BLR), but if so its net amount is small. In
both the BLR and the NLR axial symmetry is a better approximation
than spherical symmetry, but the structure no doubt is warped in many
objects, with the axis shifting from the direction of the jet in the
inner BLR to the direction of the normal to the galaxy in the outer
NLR. High-resolution long-slit spectral observation suggests the flow
in the NLR tends to be outward along the axis, perhaps with a conical
distribution, but rotational in the equatorial region, perhaps with an
inward component. Star formation occurs near many but not all AGNs. Dust
is certainly present in many if not all AGNs, and heated by radiation
it is an important source of infrared emission. Black holes appear to
exist in several nearby inactive galactic nuclei. Statistical studies
and recent imaging studies have suggested that many if not all AGNs form
or are reactivated in galaxy-galaxy interactions, including both mergers
and close passages. Theoretical calculations are beginning to show
how some of the gas in a galaxy can lose sufficient angular momentum
to fall nearly to a nucleus as a consequence of such interactions, and
thus become available as fuel. In general the evolution is expected to
occur in bursts of activity, each decreasing to zero as the available
fuel is exhausted and then restarting after the next interaction at
a higher luminosity, made possible by the now higher black hole mass.
Title: Pauper and prince. Ritchey, Hale, and big American telescopes
Authors: Osterbrock, Donald E.
Bibcode: 1993pprh.book.....O
Altcode: 1993QB36.R39O88....
No abstract at ADS
Title: Extreme Spectral Variations of the Seyfert Galaxy Markarian 993
Authors: Tran, Hien D.; Osterbrock, Donald E.; Martel, Andre
Bibcode: 1992AJ....104.2072T
Altcode:
The nuclear spectrum of the broad-line Seyfert galaxy Mrk 993 was
observed to display strong variations in the strengths of the broad
Hα and Hβ emission lines, changing its classification from a Seyfert
1 to a Seyfert 1.9. Moderate to high resolution spectra were obtained
with the IDS and CCD spectrograph on the 3 m Shane telescope at Lick
Observatory in four different epochs spanning a period of approximately
eight years. Using a spectral decomposition method which isolates the
pure emission component of the active nucleus from the contaminating
underlying host galaxy, our analysis indicates that the broad-line
fluxes varied such that the Balmer decrement steepens whenever broad
Hα and Hβ decrease in strength, and that the ionizing continuum
correspondingly reddens in slope. These direct observational evidences
suggest that variation in extinction along the line of sight to the
broad-line region of Mrk 993 provides a simple explanation to the
behavior of its spectrum, although a combination of possibilities may
also be possible.
Title: Extreme Spectral Variations of the Seyfert Galaxy MRK 993
Authors: Tran, H. D.; Osterbrock, D. E.; Martel, A.
Bibcode: 1992AAS...181.5207T
Altcode: 1992BAAS...24.1209T
The nuclear spectrum of the broad-line Seyfert galaxy Mrk 993 was
observed to display strong variations in the strengths of the broad
Hβ and Hα emission lines, changing its classification from a Seyfert
1 to a Seyfert 1.9. Moderate to high resolution spectra were obtained
with the IDS and CCD spectrograph on the 3 m Shane telescope at Lick
Observatory in four different epochs spanning a period of approximately
eight years. Using a spectral decomposition method which isolates the
pure emission component of the active nucleus from the contaminating
underlying host galaxy, our analysis indicates that the broad-line
fluxes varied such that the Balmer decrement steepens whenever broad
Hα and Hβ decrease in strength, and that the ionizing continuum
correspondingly reddens in slope. These direct observational evidences
suggest that variation in extinction along the line of sight to the
broad-line region of Mrk 993 provides a simple explanation to the
behavior of its spectrum, although a combination of possibilities may
also be possible.
Title: Obituary - Wyse, Arthur
Authors: Osterbrock, D. E.
Bibcode: 1992Mercu..21..168O
Altcode:
No abstract at ADS
Title: Science, Religion and Money: Perkins Observatory in the Great
Boom and the Great Depression 1919-1936
Authors: Osterbrock, D. E.
Bibcode: 1992AAS...181.3005O
Altcode: 1992BAAS...24.1167O
No abstract at ADS
Title: Spectroscopic Study of the CfA Sample of Seyfert Galaxies
Authors: Osterbrock, D. E.; Martel, A.
Bibcode: 1992AAS...181.5208O
Altcode: 1992BAAS...24.1209O
No abstract at ADS
Title: The Appointment of a Physicist as Director of the Astronomical
Center of the World
Authors: Osterbrock, D. E.
Bibcode: 1992JHA....23..155O
Altcode:
No abstract at ADS
Title: Book-Review - Comets - a Chronological History of Observation
Myth and Folklore
Authors: Osterbrock, D. E.
Bibcode: 1992JHA....23..217O
Altcode: 1992JHA....23..217Y
No abstract at ADS
Title: A reference system fixed in the Universe:The Lick Observatory
proper motion program
Authors: Osterbrock, D. E.
Bibcode: 1992BAAS...24.1066O
Altcode:
No abstract at ADS
Title: Book-Review - Origins and Extinctions
Authors: Osterbrock, D. E.; Raven, P. H.
Bibcode: 1992Sci...256.1578O
Altcode:
No abstract at ADS
Title: Faint Emission Lines in the Spectrum of the Orion Nebula and
the Abundances of Some of the Rarer Elements
Authors: Osterbrock, Donald E.; Tran, Hien D.; Veilleux, Sylvain
Bibcode: 1992ApJ...389..305O
Altcode:
Measurements of the emission lines, down to a faint level, in one bright
region near the Trapezium in the Orion Nebula, are reported. Most of
their measured intensities, corrected for interstellar extinction,
agree relatively well with the recombination-line theory. The measured
collisionally excited lines yield T of 9000 K, and Ne of 4000 cu cm
as the one-point representative model. Relative abundances of He, N,
O, Ne, S, Cl, Ar, Fe, and Ni are determined. They show that Fe and Ni
are depleted by about a factor of 5 with respect to the other ions,
presumably on solid particles that exist even in the strong radiation
field and hot ionized gas near the Trapezium. Permitted lines from
other elements, mostly resulting from fluorescence, but a few from
recombination, are also discussed.
Title: Near-Infrared Spectra and Classification Diagnostics of
Seyfert Galaxies
Authors: Osterbrock, Donald E.; Tran, Hien D.; Veilleux, Sylvain
Bibcode: 1992ApJ...389..196O
Altcode:
In this second paper of the series, observational results of our
spectroscopic survey of Seyfert galaxies in the near-infrared
are presented, and the potential for using emission-line ratios
in this spectral region as a classification diagnostic tool
is examined. Near-infrared CCD spectra, which cover the range
λλ7000-10000 at nominal resolution FWHM ~12 A, of 15 additional
Seyferts and two starburst galaxies were obtained with the Lick
Observatory 3 m Shane telescope. Relative emission-line intensities from
these observations, in combination with measurements from our first
paper (Osterbrock, Shaw, & Veilleux) and those of Morris &
Ward as well as additional Lick observations and measurements of new,
high signal-to- noise ratio optical spectra of many of these objects,
are used to study the diagnostic diagrams involving [S III] λλ9069,
9531/Hα, [O II] λλ7320, 7330/Hα, [S II] λλ6716, 6731/Hα, and
[O III] λ5007/Hβ. Comparisons are made in these diagrams between
observational data from the active galaxies and published measurements
of H II region-like objects as well as with predictions from simple
one-component models calculated for the two types of objects. Our
results suggest that diagnostic diagrams using near-IR lines such as
[O Il] λλ7320, 7330 and [S III] λλ9069, 9531 promise to provide
a powerful method in classifying emission-line galaxies. Most but
not all the diagnostic diagrams can be understood on the basis of
photoionization models. There may be some heating due to relativistic
electrons in addition to photoionization in active galactic nuclei
(AGNs), but this is not at all clear.
Title: Wasilewski 72: an Extragalactic H II Region
Authors: Osterbrock, Donald E.; Tran, Hien D.; Bidelman, William P.
Bibcode: 1992PASP..104..189O
Altcode:
The emission-line galaxy Was 72 was misidentified on the chart published
for it. We report the correct identification of this object, which
is an H II region type galaxy, like many of the other Wasilewski
objects. (SECTION: Galaxies)
Title: Sky Spectra at a Light-Polluted Site and the Use of Atomic
and OH Sky Emission Lines for Wavelength Calibration
Authors: Osterbrock, Donald E.; Martel, Andre
Bibcode: 1992PASP..104...76O
Altcode:
Spectra of the night sky, taken at Lick Observatory in 1988 and
1989 as byproducts of nebular spectra, show the great increase of
light pollution by sodium high-pressure and low-pressure lamps in
comparison with previous spectra taken in 1975. The usefulness of the
emission lines of the night sky spectrum for wavelength calibration is
mentioned. In the far red and near-infrared regions, where there are
only few atomic night-sky lines, the OH variation-rotation spectrum may
be used for this purpose. Accurate rest wavelengths for these lines,
calculated from the best laboratory determinations are tabulated,
and the special suitability of the P_1 (and to a lesser extent P_2)
lines are discussed. (SECTION: Instrumentation and Data Analysis)
Title: Lick Observatory Sir Galahad: Arthur B. Wyse.
Authors: Osterbrock, D. E.
Bibcode: 1991PASP..103.1118O
Altcode:
No abstract at ADS
Title: The Pauper and the Prince: Ritchey, Hale and Big American
Telescopes
Authors: Osterbrock, D. E.
Bibcode: 1991BAAS...23.1354O
Altcode:
No abstract at ADS
Title: The Nature and Structure of Active Galactic Nuclei
Authors: Osterbrock, D. E.
Bibcode: 1991BAAS...23.1351O
Altcode:
No abstract at ADS
Title: Physics, Structure, and Fueling of Active Galactic Nuclei
Authors: Osterbrock, Donald E.
Bibcode: 1991PASP..103..874O
Altcode:
are reviewed. The importance of photoionization by a hard spectrum
containing high-energy photons, extending to the X-ray region, is
emphasized. Time-variation studies plus spectral line ratios show
that simple models cannot satisfy all the observational constraints,
and some of the suggested more sophisticated models are briefly
described. Observational and theoretical results which emphasize the
importance of interactions between galaxies in refueling the accretion
disks about massive black holes at their centers are reviewed,
Title: Book-Review - Active Galactic Nuclei - I.A.U. SYMP.134 -
Santa-Cruz - California - 1988AUG15-19
Authors: Osterbrock, D. E.; Miller, J. S.; Notni, P.
Bibcode: 1991AN....312..338O
Altcode:
No abstract at ADS
Title: Ground-based Planetary Science at Lick Observatory 1888-1938
Authors: Osterbrock, D. E.
Bibcode: 1991BAAS...23.1202O
Altcode:
No abstract at ADS
Title: Active galactic nuclei
Authors: Osterbrock, D. E.
Bibcode: 1991RPPh...54..579O
Altcode:
No abstract at ADS
Title: Near-Infrared Spectra and Classification Diagnostics of
Seyfert Galaxies
Authors: Tran, H. D.; Osterbrock, D. E.; Veilleux, S.
Bibcode: 1991BAAS...23..893T
Altcode:
No abstract at ADS
Title: Faint Lines of [Fe II], [Fe III], [Ni II] and [Ni III] in
the Spectrum of NGC 1976, and Its Abundances of Fe and Ni
Authors: Osterbrock, D. E.; Tran, H. D.; Veilleux, S.
Bibcode: 1991BAAS...23..928O
Altcode:
No abstract at ADS
Title: The Appointment of a Physicist as Director of the Astronomical
Center of the World
Authors: Osterbrock, D. E.
Bibcode: 1991BAAS...23..872O
Altcode:
No abstract at ADS
Title: Book-Review - Stars and Galaxies - Citizens of the Universe
Authors: Osterbrock, D. E.
Bibcode: 1990S&T....80..381O
Altcode:
No abstract at ADS
Title: Near-Infrared Emission-Line Spectra of the Orion Nebula,
NGC 4151, and Other Seyfert Galaxies
Authors: Osterbrock, Donald E.; Shaw, Richard A.; Veilleux, Sylvain
Bibcode: 1990ApJ...352..561O
Altcode:
Near-infrared CCD spectra, covering the wavelength interval of
approximately λλ7000-11000 at moderate resolution (FWHM ~ 6 A), were
obtained of NGC 1976 and NGC 4151 in three overlapping segments. The
wavelengths and relative line fluxes were measured, and most of the
lines were identified. The strongest three lines in both objects are,
in order, [S III] λ9531, He I λ10830, and [S III] λ9069. The Orion
Nebula spectrum is very helpful for identifying lines in NGC 4151 and
for comparison with it. Among the ions identified in NGC 1976, many
of them previously known, are [Fe II], [Ni II], [Ni III], [Cl II],
and [C I]. Likewise, in NGC 4151, [C I], [Fe II], [Fe XI], [Cl II],
[Ni II], [Ar III], [Ar V], and [S II] are all present, and probably
[S VIII] as well, in addition to H I, He I, and He II. Lower resolution
(FWHM ~ 12 A) spectra covering the range λλ7000-10000 of 14 additional
Seyfert galaxies were also obtained and measured. The strongest line
in all but two of them is [S III] λ9531. Nearly all these galaxies
show the strongest [Ni II] line, λ7378. Comparison of line strengths
among these various Seyfert galaxies allow the ionization behavior
to be traced. One unidentified line, λ7865, that is present in the
spectra of NGC 4151, III Zw 77, and three other galaxies, is probably a
high-ionization forbidden line. Two other unidentified emission lines
apparently observed in two or more Seyfert galaxies are λ9138 and
λ9191. The best additional diagnostic information the near-infrared
spectral region provides, the [S III] (λ9069 + λ9531)/λ6312 ratio,
is not as useful as the analogous [O III] ratio, due to the blending
of λ6312 and the greater wavelength interval of the [S III] ratio.
Title: C III] λ1909 and the Electron Densities in the Broad-Line
Regions of Active Galactic Nuclei Revisited
Authors: Osterbrock, D. E.
Bibcode: 1990BAAS...22..847O
Altcode:
No abstract at ADS
Title: Book-Review - Stars and Galaxies - Citizens of the Universe
Authors: Osterbrock, D. E.
Bibcode: 1990AstQ....7..250O
Altcode:
No abstract at ADS
Title: Self-Made Cosmologist: The Education of Edwin Hubble
Authors: Osterbrock, Donald E.; Brashear, Ronald S.; Gwinn, Joel A.
Bibcode: 1990ASPC...10....1O
Altcode: 1990eug..symp....1O
No abstract at ADS
Title: Young Edwin Hubble
Authors: Osterbrock, D. E.; Brashear, R. S.; Gwinn, J. A.
Bibcode: 1990Mercu..19....2O
Altcode:
No abstract at ADS
Title: Astronomy's `Crisis' Through Another Lens
Authors: Walstad, Allan; Osterbrock, Donald E.
Bibcode: 1990PhT....43k.120W
Altcode:
No abstract at ADS
Title: Stars and galaxies : citizens of the universe : readings from
Scientific American magazine
Authors: Osterbrock, Donald E.
Bibcode: 1990sgcu.book.....O
Altcode: 1990QB857.S73......
No abstract at ADS
Title: Armin O. Leuschner and the Berkeley astronomical department
Authors: Osterbrock, Donald E.
Bibcode: 1990AstQ....7...95O
Altcode:
No abstract at ADS
Title: The funding crisis in astronomy.
Authors: Osterbrock, D. E.
Bibcode: 1990PhT....43a..71O
Altcode:
No abstract at ADS
Title: The Optical Counterpart of the Radio Source Close to the
Seyfert 2 Nucleus of NGC 5953 = ARP 91 B
Authors: Rafanelli, P.; Osterbrock, D. E.; Pogge, R. W.
Bibcode: 1990AJ.....99...53R
Altcode:
Spectroscopic and morphological observations of the nuclear region of
the Seyfert 2 galaxy NGC 5953=Arp 91 B are presented. It is shown that
an extended emitting region, with features typical of a supergiant H II
region, is located to the west of the nucleus within a radio structure
which is emitting as a nonthermal source with spectral index α=0.6
in the 1.4-5.0 GHz range. The faintness of the [0 III] λλ4959, 5007
emission lines in the spectrum of this region is discussed in terms
of a state of low ionization, and high abundances of heavy elements in
the emitting gas. In addition, the possibility that the ionization is
produced by the Seyfert 2 nucleus and that its luminosity has undergone
an abrupt decrease in luminosity has been taken into account. The
nonthermal radio emission is tentatively interpreted as the result of
frequent supernova blasts and the consistency of this interpretation
with the optical data is discussed. Another extended emitting region,
located close to the nucleus to its east, in a position symmetrically
opposite to the western region, is revealed by our spectra. Its line
ratios and fluxes are typical of a very luminous giant H II region. A
bright stellar "knot," located 3" west of the nucleus, just within
the emitting region associated with the extended radio source, is a
foreground star of spectral type F8-G2 and magnitude V~16.
Title: McVittie and the American Astronomical Society
Authors: Osterbrock, Donald E.; Fredrick, Laurence W.; Edmondson,
Frank K.; Schwarzchild, Martin
Bibcode: 1990VA.....33...75O
Altcode: 1988VA.....33...75O
Four letters were read to the RAS Symposium, from Donald Osterbrock,
Laurence W.Fredrick, Frank K.Edmondson and Martin Schwatzschild, on
the major role played by George McVittie as Secretary of the American
Astronomical Society. Extracts from these letters are reproduced
below. (Ed.)
Title: The observational approach to cosmology: U. S. Observatories
pre-World War II
Authors: Osterbrock, Donald E.
Bibcode: 1990mcr..book..247O
Altcode:
No abstract at ADS
Title: Active galactic nuclei
Authors: Osterbrock, Donald E.
Bibcode: 1989NYASA.571...99O
Altcode: 1989txra.symp...99O
Recent observational and theoretical investigations of AGN are
reviewed. The basic AGN characteristics (broad emission lines of
abundant ions, X-ray emission, and a sharp starlike appearance)
are summarized, and particular attention is given to the spectral
classification of Seyfert galaxies, the AGN velocity fields and their
measurement, low-ionization narrow-emission-line regions (LINERs),
observations supporting a torus model of Seyfert AGN, extended gas and
ionization, and the black-hole/accretion-disk model of the AGN energy
source. It is suggested that no one model can explain the physical
processes in all types of AGN.
Title: Book-Review - Astrophysics of Gaseous Nebulae and Active
Galactic Nuclei
Authors: Osterbrock, D. E.; Bochkarev, N. G.
Bibcode: 1989SvA....33..694O
Altcode:
No abstract at ADS
Title: Book-Review - Astrophysics of Gaseous Nebulae and Active
Galactic Nuclei
Authors: Osterbrock, D. E.
Bibcode: 1989S&T....78..491O
Altcode:
No abstract at ADS
Title: Leuschner, Armin and the Berkeley Astronomical Department
Authors: Osterbrock, D. E.
Bibcode: 1989PASP..101..885O
Altcode:
No abstract at ADS
Title: George Willis Ritchey, Captain J. F. Hellweg, and the Building
of the U. S. Naval Observatory Ritchey-Chrétien Reflector
Authors: Osterbrock, D. E.
Bibcode: 1989BAAS...21.1230O
Altcode:
No abstract at ADS
Title: High-Dispersion CCD Spectra of NGC 1976, the Orion Nebula
Authors: Osterbrock, D. E.; Veilleux, S.; Tran, H. D.
Bibcode: 1989BAAS...21.1141O
Altcode:
No abstract at ADS
Title: Self-Made Cosmologist: The Education of Edwin Hubble
Authors: Brashear, R. S.; Osterbrock, D. E.; Gwinn, J. A.
Bibcode: 1989BAAS...21.1227B
Altcode:
No abstract at ADS
Title: To Climb the Highest Mountain - W.W. Campbell's 1909 Mars
Expedition to Mount-Whitney
Authors: Osterbrock, D. E.
Bibcode: 1989JHA....20...77O
Altcode:
No abstract at ADS
Title: Lick Observatory - the First Century
Authors: Osterbrock, D. E.
Bibcode: 1989PASP..101..434O
Altcode:
No abstract at ADS
Title: W. W. Campbell of Lick Observatory: The Creative Scientist
Who Became a Radial-Velocity Factory Manager
Authors: Osterbrock, D. E.
Bibcode: 1989BAAS...21..753O
Altcode:
No abstract at ADS
Title: Astrophysics of gaseous nebulae and active galactic nuclei
Authors: Osterbrock, Donald E.
Bibcode: 1989agna.book.....O
Altcode: 1989QB855.55.O88...
This graduate-level text/reference covers gaseous nebulae and the
emission regions in Seyfert galaxies, quasars, and other types of
active galactic nuclei. Written by a world-renowned expert in the field,
this book is invaluable for graduate students and researchers in this
important research area.
Title: Near-Infrared Emission-Line Spectra of the Orion Nebula,
NGC 4151, and Other Seyfert Galaxies
Authors: Osterbrock, D. E.; Shaw, R. A.; Veilleux, S.
Bibcode: 1989IAUS..134..298O
Altcode:
No abstract at ADS
Title: Active galactic nuclei: proceedings of the 134th Symposium of
the International Astronomical Union, held in Santa Cruz, California,
August 15-19, 1988.
Authors: Osterbrock, Donald E.; Miller, Joseph S.
Bibcode: 1989IAUS..134.....O
Altcode:
No abstract at ADS
Title: Book Review: The cold light of dawn. / U of Toronto Press, 1988
Authors: Osterbrock, D. E.
Bibcode: 1988Sci...242.1583O
Altcode:
No abstract at ADS
Title: Near-Infrared Emission-Line Spectra of the Orion Nebula,
NGC 4151, and Other Seyfert Galaxies
Authors: Osterbrock, D. E.; Shaw, R. A.; Veilleux, S.
Bibcode: 1988BAAS...20.1032O
Altcode:
No abstract at ADS
Title: Don Menzel at Lick: A Young Theoretical Astrophysicist at an
Old Observational Observatory
Authors: Osterbrock, D. E.
Bibcode: 1988BAAS...20..984O
Altcode:
No abstract at ADS
Title: Book-Review - Eye on the Sky
Authors: Osterbrock, D. E.; Gustafson, J. R.; Unruh, W. J. S.; Bell,
T. E.
Bibcode: 1988S&T....76..260O
Altcode:
No abstract at ADS
Title: Book-Review - Eye on the Sky - Lick Observatory's First Century
Authors: Osterbrock, D. E.; Gustafson, J. R.; Unruh, W. J. S.;
Kinder, A.
Bibcode: 1988JBAA...98..261O
Altcode:
No abstract at ADS
Title: Book-Review - Eye on the Sky - Lick Observatory's First Century
Authors: Osterbrock, D. E.; Gustafson, J. R.; Unruh, W. J. S.
Bibcode: 1988Sci...241..734O
Altcode:
No abstract at ADS
Title: Book-Review - Eye on the Sky - Lick Observatory's First Century
Authors: Osterbrock, D. E.; Gustafson, J. R.; Shiloh-Unruh, W. J.
Bibcode: 1988JBAA...98R.212O
Altcode:
No abstract at ADS
Title: The Physics of Gaseous Nebulae
Authors: Osterbrock, Donald E.
Bibcode: 1988PASP..100..412O
Altcode:
This paper is one of the invited reviews celebrating the centenary
of the Astronomical Society of the Pacific. The paper by I. S. Bowen
(004.068) of 60 years ago is reviewed and used as the starting point for
a review of nebular astrophysics. Two important aspects in the growth
of our understanding of nebulae are stressed: improved observational
data covering a wide wavelength region, from the ultraviolet through
the optical and infrared to the radio spectral region, and improved
computational power based on ever-larger computers.
Title: Book-Review - Eye on the Sky - Lick Observatory's First Century
Authors: Osterbrock, D. E.; Gustafson, J. R.; Unruh, W. J. S.;
Devorkin, D. H.
Bibcode: 1988Natur.332..747O
Altcode:
No abstract at ADS
Title: The Relative Number of Seyfert 2 Galaxies. I. Spectra of
Emission-Line Galaxies in the Wasilewski Field
Authors: Osterbrock, Donald E.; Shaw, Richard A.
Bibcode: 1988ApJ...327...89O
Altcode:
Slit spectra were obtained of all the Seyfert galaxy candidates
and many other emission-line galaxies discovered (or recovered)
by Wasilewski in his objective-prism survey centered on the region
of the north Galactic pole. Redshifts and relative emission-line
fluxes were measured for these galaxies, and all of their spectra were
classified. Among the Wasilewski candidates, Was 26 is a Seyfert 1, Was
45 is a Seyfert 1.9, and Was 2 and Was 31 are Seyfert 2 galaxies. The
other Seyfert 2 candidates he identified are actually H II region
galaxies. Including previously known Seyfert galaxies in this region,
it is confirmed that the relative number of Seyfert 2 galaxies, down
to a given apparent magnitude, is large. Per unit volume of space,
the relative numbers of Seyfert (1 + 1.5) to Seyfert (1.8 + 1.9) to
Seyfert 2 are approximately 0.1/0.1/0.8. If the same galaxies were to
evolve through all these stages, they would spend most of their AGN
lifetimes as Seyfert 2s. If all Seyfert nuclei were similar objects
with central broad-line regions hidden by obscuring disks to various
extents, the disks would be thick and the line broadening due to any
presumed rotational or radial velocity field in the plane of the disk
would be greatly reduced by projection effects.
Title: Lick Observatory - the First Century
Authors: Osterbrock, D. E.
Bibcode: 1988Mercu..17...34O
Altcode:
No abstract at ADS
Title: Emission Line Spectra and the Nature of Active Galactic Nuclei
Authors: Osterbrock, Donald E.
Bibcode: 1988LNP...307....1O
Altcode: 1988agn..conf....1O
Seyfert galaxy emission-line spectra provide clues to the
structure of active galactic nuclei and the nature of their central
sources. Classification of their spectra organizes a wide range
of properties; they do not all fit into a single one-parameter
sequence. The luminosity functions of the individual types provide
constraints on their evolution and on possible geometries, but are
difficult to determine because objective-prism and color surveys
tend to be most efficient in finding blue objects. The IRAS survey has
identified many more Seyfert 2 galaxies, which tend on the average to be
more heavily reddened than the previously known objects. The discovery
of very faint broad Ha emission components in many emission-line
galaxies by Filippenko and Sargent indicates the continuity of the
general AGN process to very low luminosity levels. The narrow-line
profiles of all types of Seyfert galaxies have the same general form,
indicating a single type of velocity field. It is evidently mostly
radial, but not necessarily spherical. There are differences in
detail, which on the average tend to be correlated with the spectral
type, but these are by no means invariably followed at the level of
individual galaxies. The broad-line profiles show a great range in
properties. Combinations of radial and rotational velocity fields give
the best fits with the observed profiles, but there are theoretical
difficulties with this picture, particularly with rotational flow.
Title: Eye on the sky. Lick Observatory's first century
Authors: Osterbrock, Donald E.; Gustafson, John R.; Unruh, W. J. Shiloh
Bibcode: 1988eslo.book.....O
Altcode: 1988QB82.U62M686...
No abstract at ADS
Title: Eye on the Sky: Lick Observatory's First Century and James
E. Keeler: Pioneer American Astrophysicist (and the Early Development
of American Astrophysics)
Authors: Osterbrock, Donald E.; Gustafson, John R.; Shiloh Unruh,
W. J.; Greenstein, Jesse L.
Bibcode: 1988PhT....41h..76O
Altcode:
No abstract at ADS
Title: Origins and extinctions : based on a Symposium on Life and
the Universe, held at the National Academy of Sciences, Washington,
D.C., April 30, 1986
Authors: Osterbrock, Donald E.; Raven, Peter H.; Guth, Alan H.
Bibcode: 1988orex.conf.....O
Altcode:
No abstract at ADS
Title: Optical Spectra of Narrow Emission Line Palomar-Green Galaxies
Authors: Osterbrock, Donald E.; Pogge, Richard W.
Bibcode: 1987ApJ...323..108O
Altcode:
Spectra were obtained of 35 of the 36 narrow emission line galaxies
isolated in the Palomar-Green (PG) survey of Green, Schmidt, and Liebert
(1986). Of these, three are narrow-line Seyfert 1 galaxies, three more
are Seyfert 1.5 galaxies, and only one, PG 2259 + 157 = NGC 7465 =
Mrk 313, is a relatively low-ionization active galactic nucleus,
a marginal Seyfert 2 with forbidden O III line 5007/H-beta of about
3. The rest are H II region galaxies, as is CSO 177, a candidate Seyfert
2 galaxy not previously observed at H-alpha. Redshifts and relative
emission-line strengths are given for all these galaxies. These spectra
confirm that a survey such as the PG, based on ultraviolet excesses,
though good for finding QSOs, is not well suited for finding Seyfert
2 galaxies. However, the PG survey shows that a significant number of
Seyfert 1 galaxies are 'narrow-line' objects with H I emission-line
full widths at half-maximum equal to or less than 2000 km/s.
Title: Lick Observatory: The First Century
Authors: Osterbrock, D. E.; Kraft, R. P.; Miller, J. S.; Popper,
D. M.; Preston, G. W.; Vasilevskis, S.
Bibcode: 1987BAAS...19.1044O
Altcode:
No abstract at ADS
Title: Spectra of Second Byurakan Survey and Other Seyfert Galaxy
Candidates
Authors: Osterbrock, D. E.
Bibcode: 1987BAAS...19.1069O
Altcode:
No abstract at ADS
Title: The Ultraviolet and Optical Emission-Line Spectrum of III ZW 77
Authors: Ferland, Gary J.; Osterbrock, Donald E.
Bibcode: 1987ApJ...318..145F
Altcode:
The high-ionization Seyfert I galaxy III Zw 77 has been simultaneously
observed over the satellite ultraviolet to near-IR spectral
regions. As in other AGN, the continuous energy distribution shows
a roughly power-law decline across much of the optical region and a
flatter-than-unity spectral index in the near-UV. The equivalent widths
of the Balmer lines and Ly-alpha are very similar to those found in
other AGN. The UV-to-optical emission-line spectrum for narrow lines
is fairly similar to those deduced for Seyfert 2 galaxies. A surprising
result is the detection of the semiforbidden O III 1661, 1666 A doublet
with an intensity indicating high temperatures more suggestive of shock
heating than photoionization equilibrium. An interpretation in terms
of a multicomponent photoionized structure is proposed in which dense
regions produce the UV lines and the lower density regions produce
the optical lines.
Title: Spectral Classification of Emission-Line Galaxies
Authors: Veilleux, Sylvain; Osterbrock, Donald E.
Bibcode: 1987NASCP2466..737V
Altcode: 1987sfig.conf..737V
A revised method of classification of narrow line active galaxies and H
II region-like galaxies is proposed. It involves the line ratios (O III)
lambda 5007/H beta, (N II) lambda 6583/H alpha, (S II) (lambda lambda
6716 = 6731)/H alpha, and (O I) lambda 6300/H alpha. These line ratios
take full advantage of the physical distinction between the two types
of objects and minimize the effects of reddening correction and errors
in the flux calibration. Large sets of internally consistent data are
used including new previously unpublished measurements. Prediction of
recent photoionization models by power law spectra and by hot stars
are compared with the observations. The classification is based on
the observational data interpreted on the basis of these models.
Title: Spectral Classification of Emission-Line Galaxies
Authors: Veilleux, Sylvain; Osterbrock, Donald E.
Bibcode: 1987ApJS...63..295V
Altcode:
A revised method of classification of narrow-line active galaxies and H
II region-like galaxies is proposed. It involves the line ratios which
take full advantage of the physical distinction between the two types
of objects and minimize the effects of reddening correction and errors
in the flux calibration. Large sets of internally consistent data are
used, including new, previously unpublished measurements. Predictions
of recent photoionization models by power-law spectra and by hot stars
are compared with the observations. The classification is based on
the observational data interpreted on the basis of these models.
Title: Quasars, Seyfert galaxies and active galactic nuclei
Authors: Osterbrock, D. E.
Bibcode: 1987soap.conf...59O
Altcode: 1987sap..book...59O
An overview of the spectroscopic characteristics of plasmas in the
cores of quasars, Seyferts, and AGN is given. Observational aspects
are discussed; typical data are compiled in tables and graphs;
and sample spectra are shown. Particular attention is given to the
narrow-line and broad-line regions, high-energy photons, UV spectra,
and physical models.
Title: Skyfert Galaxies: Classification, Morphology, Observations
at Optical of Wavelengths, Environmental Factors Seyferts
Authors: Osterbrock, D. E.
Bibcode: 1987IAUS..121..109O
Altcode:
Recent optical work on Seyfert galaxies is summarized, particularly on
their spectral classification, morphology, companions, and presence
in clusters of galaxies. Their general continuity with QSOs and with
Liners is emphasized. Methods of finding additional Seyfert galaxies
and of assembling a complete sample for investigating the luminosity
function of AGNs are also discussed.
Title: Stranger in a Strange Land - Donald H. Menzel - First
Theoretical Astrophysicist on the Lick Observatory Staff
Authors: Osterbrock, D. E.
Bibcode: 1986PASP...98.1112O
Altcode:
No abstract at ADS
Title: Spectral Classification of Emission-Line Galaxies
Authors: Osterbrock, D. E.; Veilleux, S.
Bibcode: 1986PASP...98R1106O
Altcode:
No abstract at ADS
Title: Markarian 490 : a high-ionization starburst galaxy.
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1986PASP...98.1102D
Altcode:
No abstract at ADS
Title: Number Two Club: How Lick Observatory Finally Got Its Second
Largest Telescope in the World
Authors: Osterbrock, D. E.
Bibcode: 1986BAAS...18.1054O
Altcode:
No abstract at ADS
Title: A Spectroscopic Survey of AGNs Near the North Galactic Pole
Authors: Shaw, R. A.; Osterbrock, D. E.
Bibcode: 1986BAAS...18.1039S
Altcode:
No abstract at ADS
Title: Optical Spectra of Narrow Emission-Line PG Galaxies and of
CSO 177
Authors: Osterbrock, D. E.; Pogge, R. W.
Bibcode: 1986BAAS...18.1002O
Altcode:
No abstract at ADS
Title: An Astrophysical Concept. (Book Reviews: Accretion Power
in Astrophysics)
Authors: Osterbrock, Donald E.
Bibcode: 1986Sci...233..582O
Altcode:
No abstract at ADS
Title: An Astrophysical Concept. (Book Reviews: Accretion Power
in Astrophysics)
Authors: Osterbrock, Donald E.
Bibcode: 1986Sci...233..582F
Altcode:
No abstract at ADS
Title: Markarian 490 : a high-ionization starburst galaxy.
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1986PASP...98..629D
Altcode:
Spectra of the galaxy Mrk 490 are described. Three components
of this object may be recognized: (1) the nucleus of the galaxy;
(2) probably a luminous H II region complex close to it; and (3)
either a more distant H II region or the nucleus of a smaller galaxy
physically related to (1). All have high-ionization emission-line
spectra indicating photoionization by early-type stars. Component (3)
has especially high ionization and large equivalent width of H-beta,
indicating a population unusually rich in very hot stars.
Title: Book-Review - James E. Keeler - Pioneering American
Astrophysicist
Authors: Osterbrock, D.
Bibcode: 1986Mercu..15...90O
Altcode:
No abstract at ADS
Title: Failure and Success - Two Early Experiments with Concave
Gratings in Stellar Spectroscopy
Authors: Osterbrock, D. E.
Bibcode: 1986JHA....17..119O
Altcode:
No abstract at ADS
Title: Book-Review - James E. Keeler Pioneer American Astrophysicist
and the Early Development of American Astrophysics
Authors: Osterbrock, D. E.; Pecker, J. C.
Bibcode: 1986SSRv...43..386O
Altcode:
No abstract at ADS
Title: Nicholas T. Bobrovnikoff and the Scientific Study of Comet
Halley 1910
Authors: Osterbrock, D. E.
Bibcode: 1986Mercu..15...46O
Altcode:
No abstract at ADS
Title: An Analysis of the Narrow-Line Profiles in Seyfert 2 Galaxies
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1986ApJ...301..727D
Altcode:
An analysis of the line profiles in 18 high-ionization Seyfert 2
galaxies is presented. Two-thirds of the sample show a correlation
between emission-line width and critical density. Few objects show
a correlation between line width and ionization potential. The data
argue strongly for a model in which optically thick emission-line
clouds occupy regions of highest density and velocity dispersion. A
correlation was found between the Hβ emission-line equivalent width
and the line widths for all emission lines. According to the relation,
all narrow-line widths tend to 320±25 km s-1 as the Hβ
emission-line equivalent width approaches zero. A comparison between
Seyfert 2 line profiles and the corresponding Seyfert 1 narrow-line
profiles is included. The significant profile differences between
Seyfert 1s and 2s argue in a statistical sense against evolution between
types on short time scales, and that Seyfert 2s are not highly reddened
Seyfert 1s.
Title: Preserving Astronomical Papers
Authors: Schaumberg, D.; Osterbrock, D.
Bibcode: 1986Mercu..15...19S
Altcode:
No abstract at ADS
Title: NGC 1320: A Feeble, High-Ionization Seyfert 2 Galaxy
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1986ApJ...301...98D
Altcode:
Emission-line strengths and widths are reported for NGC 1320,
a Seyfert 2 galaxy that is unusual in having both a quite high
ionization spectrum, as well as rather narrow lines and a relatively
weak featureless continuum. The narrow-line region is evidently quite
small in this galaxy, and the observed gas has not been accelerated
to velocities as high as the velocities observed in most other Seyfert
galaxies.
Title: Nicholas T. Bobrovnikoff and the scientific study of comet
Halley 1910.
Authors: Osterbrock, D. E.
Bibcode: 1986IHWN....9...26O
Altcode:
No abstract at ADS
Title: Seyfert galaxies in the Universe.
Authors: Osterbrock, D. E.
Bibcode: 1986ASSL..121..193O
Altcode: 1986seag.conf..193O
Recent optical spectroscopy of Seyfert galaxies, particularly at Lick
Observatory, is discussed. The frame of reference is the luminosity
function of Seyfert galaxies, the incompleteness of available surveys,
and how complete samples can be found by combining several different
types of surveys. The importance of spectral classification, or
differentiating between various classes of active galactic nuclei,
is stressed. All Seyfert galaxies and AGNs cannot be fitted into
a single one-parameter sequence. Starburst galaxies and Liners are
briefly discussed. At the end some recent results on the frequencies
of Seyfert galaxies with companions and in interacting systems are
briefly summarized.
Title: IUE Spectra and a Resulting Model of Seyfert 2 Galaxies
Authors: Ferland, G. J.; Osterbrock, D. E.
Bibcode: 1986ApJ...300..658F
Altcode:
Nearly simultaneous optical and ultraviolet observations of several
Seyfert 2 galaxies are presented. A mean optical to ultraviolet
emission line spectrum for Seyfert 2 galaxies is determined, and
these intensities are compared with predictions of photoionization
models. The UV to X-ray nonthermal continuum which ionizes this gas is
examined. The results suggest that an obscuring layer does not hide
an underlying broad-line region, and that narrow-line objects such
as Seyfert 2 and narrow-line radio galaxies are physically different
from broad-line objects, at least in not having an inner broad-line
region. The absence of extinction also distinguishes these classical
Seyfert 2 galaxies from the narrow-line X-ray galaxies, which X-ray
evidence suggests may be extinguished Seyfert 1 galaxies.
Title: Emission-line regions of active galaxies and QSOs.
Authors: Osterbrock, Donald E.; Mathews, William G.
Bibcode: 1986ARA&A..24..171O
Altcode:
Recently acquired narrow- and broad-line spectroscopic data on active
galactic nuclei and QSOs are reviewed, along with models which have been
developed for the physical conditions producing the emissions. Attention
is given to data on the structures and velocity fields of the ionized
gas in Seyfert 1 and 2 galaxies, including interconnections between
broad(BLR) and narrow-line (NLR) regions. Features and deficiencies
of cloud models for describing the dynamics of BLRs and the
less-complicated NLRs, and non-cloud models for BLRs are discussed.
Title: Optical spectra of IRAS "warm" galaxies.
Authors: Osterbrock, D. E.; De Robertis, M. M.
Bibcode: 1985PASP...97.1129O
Altcode:
Redshifts, relative emission-line-intensity measurements, and optical
spectral classifications are presented for 30 galaxies selected by the
IRAS observers as Seyfert candidates on the basis of their infrared
properties. The authors confirm earlier results that a large number
of these objects are indeed previously unknown Seyfert galaxies, most
of them Seyfert 2s. These IRAS Seyfert 2 galaxies as a group are at
relatively small redshift, and thus represent a low-luminosity tail
of the Seyfert galaxy luminosity function. There are in addition
a significant number of Liners among them, as well as H II region
galaxies. Many of the IRAS Seyfert 2 and H II region galaxies have line
spectra that are significantly more heavily reddened than samples of
previously known objects of these types.
Title: Optical spectra of IRAS "warm" galaxies.
Authors: Osterbrock, D. E.; Derobertis, M. M.
Bibcode: 1985PASP...97R.902O
Altcode: 1985PASP...97..902O
No abstract at ADS
Title: Henry Crew and an Early Astronomical Concave Grating
Spectrograph
Authors: Osterbrock, D. E.
Bibcode: 1985PASP...97..906O
Altcode:
No abstract at ADS
Title: The spectra of narrow-line Seyfert 1 galaxies.
Authors: Osterbrock, D. E.; Pogge, R. W.
Bibcode: 1985ApJ...297..166O
Altcode:
Measurements are presented of a group of active galactic nuclei with all
the properties of Seyfert 1 or 1.5 galaxies, but with unusually narrow
H I lines. They include Mrk 42, 359, and 1239 as well as Mrk 493, 766,
783, and 1126. One other somewhat similar object, Mrk 1388, is also
included in the discussion. For these objects, narrow-line widths
and intensities of the emission lines are discussed. Overall, these
narrow-line Seyfert 1 galaxies show a wide variety of deviations from
the properties of typical Seyfert 1 objects. They clearly demonstrate
that the Seyfert phenomenon is not a simple one-parameter effect.
Title: Seyfert Galaxies, Liners, and H II Region Galaxies Among the
IRAS Warm Galaxies
Authors: Osterbrock, D. E.; De Robertis, M. M.
Bibcode: 1985BAAS...17..868O
Altcode:
No abstract at ADS
Title: Nicholas T. Bobrovnikoff and the Scientific Study of Comet
Halley 1910
Authors: Osterbrock, D. E.
Bibcode: 1985BAAS...17..828O
Altcode:
No abstract at ADS
Title: Book-Review - James E. Keeler - Pioneer American Astrophysicist
Authors: Osterbrock, D. E.; Meadows, A. J.
Bibcode: 1985JBAA...95..243O
Altcode:
No abstract at ADS
Title: Book-Review - James E. Keeler - Pioneer American Astrophysicist
Authors: Osterbrock, D. E.; Stickland, D.
Bibcode: 1985Obs...105..146O
Altcode:
No abstract at ADS
Title: The splitting of the 2S2 2p3 2P term in O II.
Authors: De Robertis, M. M.; Osterbrock, D. E.; McKee, C. F.
Bibcode: 1985ApJ...293..459D
Altcode:
The O II 2p3 2P(1/2)-2P(3/2) and 2D(3/2)-2D(5/2) splitting in
high-dispersion long-slit CCD spectra of the bright planetary
nebula NGC 7027 has been measured. Techniques used to deblend the
2D(5/2)-2P(3/2),(1/2), 2D(3/2)-2P(3/2,1/2) pairs of lines are described
and applied to the data. Accurate separations of the 2P, 2D levels
are determined to be 2.00 + or -0.03/cm and 20.11 + or -0.07/cm,
respectively. Improved energy level values and improved wavelengths
for forbidden O II are listed. The appropriate forbidden O II 2p3 2P
line ratios can provide good estimates of the density in the plasma and
reddening along the line of sight. The 2P(1/2)-2P(3/2) transition at 60
GHz falls within an atmospheric O2 band at the same frequency and has a
rather small transition probability, so it is unlikely to be observable.
Title: The Nature of Saturn's Rings - Keeler's Prettiest Application
of Doppler's Principle
Authors: Osterbrock, D. E.
Bibcode: 1985Mercu..14...46O
Altcode:
No abstract at ADS
Title: Book-Review - James E. Keeler Pioneer American Astrophysicist
Authors: Osterbrock, D. E.; Schorn, R. A.
Bibcode: 1985S&T....69..323O
Altcode:
No abstract at ADS
Title: Rudolph Minkowski: Observational astrophysicist
Authors: Osterbrock, Donald E.
Bibcode: 1985PhT....38d..50O
Altcode:
No abstract at ADS
Title: An Analysis of the Narrow-Line Profiles in Seyfert 2 Galaxies
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1985BAAS...17..587D
Altcode:
No abstract at ADS
Title: The hydrogen line spectra of narrow-line radio galaxies.
Authors: Ferland, G. J.; Osterbrock, D. E.
Bibcode: 1985ApJ...289..105F
Altcode:
The results of the first detection of Ly-alpha in a narrow-line radio
galaxy are reported. Nearly simultaneous optical and UV observations
of 3C 192 and 3C 223 allow the measurement of both Balmer and
Lyman decrements. These line ratios are approximate functions of the
interstellar reddening and of a parameter which is proportional to the
amount of H I collisional excitation present. The reddening of 3C 192
is slightly larger than that due to the Galaxy, although 3C 223 may
have a larger value. Both galaxies have intrinsic Balmer and Lyman
decrements which are significantly steeper than case B, suggesting
that the gas is photoionized by a fairly hard X-ray continuum. The
deduced values of L-alpha/H-beta and H-alpha/H-beta compare favorably
with predictions of recent models.
Title: Ritchey Biography
Authors: Osterbrock, D. E.
Bibcode: 1985S&T....69..100O
Altcode:
No abstract at ADS
Title: Book-Review - James E. Keeler - Pioneer American Astrophysicist
and the Early Development of American Astrophysics
Authors: Osterbrock, D. E.; Fritze, K.
Bibcode: 1985AN....306..340O
Altcode:
No abstract at ADS
Title: Observations of broad emission-line regions
Authors: Osterbrock, D. E.
Bibcode: 1985aagq.conf..111O
Altcode:
Recent observational results bearing on the structure and velocity field
of the broad-line region are discussed. Variations in the strength and
form of the broad H I profiles give estimates of the size, and hence
density in this region. In some cases densities as high as Ne
of about 10 to the 11th/cu cm are indicated. High quality spectral
data show that the profiles of different broad lines in a given AGN
are not identical, indicating ionization differences with velocity,
and thus with position in the nucleus. Many lines of evidence show that
a simple dichotomy between the broad and narrow emission-line regions
is too simple, and that in many ways they merge continuously into
one another. A physical picture that fits most of the observational
measurements is that the structure is cylindrically symmetric, with
slow inward flow in a rotating plane, and fast radial winds in cones
or cylindrical regions perpendicular to the disk or at least outside
it. There is a wide range of densities, and the denser regions on the
average have higher velocities than the less dense regions.
Title: The Quest for More Photons - how Reflectors Supplanted
Refractors as the Monster Telescopes of the Future at the End of
the Last Century
Authors: Osterbrock, Donald E.
Bibcode: 1985AstQ....5...87O
Altcode:
No abstract at ADS
Title: Markarian 1388 - a high-ionization narrow-line Seyfert galaxy.
Authors: Osterbrock, D. E.
Bibcode: 1985PASP...97...25O
Altcode:
The spectrum of the Seyfert galaxy Mrk 1388 is described. It is unusual
in having strong high-ionization lines (in particular, the forbidden
lines of Fe VII and Fe X) and a strong featureless continuum, but narrow
H I lines with essentially the same widths as the forbidden lines. The
spectrum thus combines characteristics usually found separately in
Seyfert 1 and Seyfert 2 galaxies.
Title: An analysis of the narrow-line profiles in high ionization
Seyfert galaxies.
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1984ApJ...286..171D
Altcode:
A Fourier deconvolution technique was used to analyze the narrow
optical emission-line profiles for 12 high-ionization Seyfert
galaxies corresponding to a wide range of ionization potential. A good
correlation is found between line width and critical density. For a
given object, the ratio of line widths at various fractions of full
intensity were similar over the entire range of ionization potential
and critical density. Almost identical velocity ratios were found
for the forbidden line of FE VII (6087 A) taken from every object,
suggesting a similar acceleration mechanism (and/or geometry) for all
objects in both the narrow-line and broad-line regions. High-ionization
line widths correlated poorly with the absolute blue magnitude of the
galaxy, while the lower ionization lines showed good correlation. On
average, half of the galaxies have narrow line profiles which are
skewed to the blue, and half of those are symmetric. High ionization
lines had predominantly blue excesses. Some possible implications
of the correlations are discussed, and detailed descriptions of the
individual spectra are presented.
Title: Book Review: Realm of the Long Eyes: A brief history of
Kitt Peak National Observatory. James E. Kloeppel. Univelt, Inc.,
San Diego, California, 1983. 136 pp, $15.00.
Authors: Osterbrock, Donald E.
Bibcode: 1984Icar...60..429O
Altcode:
No abstract at ADS
Title: Spectra of emission-line galaxies in Wasilewski's North
galactic polefield.
Authors: Osterbrock, D. E.
Bibcode: 1984PASP...96..792O
Altcode:
No abstract at ADS
Title: The Rise and Fall of Edward S. Holden - Part Two
Authors: Osterbrock, D. E.
Bibcode: 1984JHA....15..151O
Altcode:
No abstract at ADS
Title: An analysis of the narrow-line profiles in high-ionization
Seyfert galaxies.
Authors: De Robertis, M. M.; Osterbrock, D. E.
Bibcode: 1984PASP...96R.787D
Altcode:
No abstract at ADS
Title: Spectra of emission-line galaxies in Wasilewski's north
galactic polefield.
Authors: Osterbrock, D. E.
Bibcode: 1984PASP...96R.792O
Altcode:
No abstract at ADS
Title: Mrk 1388 and Other High-Ionization Narrow-Line Seyfert Galaxies
Authors: Osterbrock, D. E.; Pogge, R. W.
Bibcode: 1984BAAS...16..987O
Altcode:
No abstract at ADS
Title: The Rise and Fall of Edward S. Holden: Part 1
Authors: Osterbrock, D. E.
Bibcode: 1984JHA....15...81O
Altcode:
No abstract at ADS
Title: The luminosity function of Seyfert galaxies and the cluster
3C 295.
Authors: Osterbrock, D. E.
Bibcode: 1984ApJ...280L..43O
Altcode:
The apparently high percentage of Seyfert galaxies (three objects) found
in the 3C 295 cluster by Dressler and Gunn (1982) is discussed. Among
field galaxies, the fraction that are Seyfert galaxies is large at
the very brightest absolute magnitudes, but drops abruptly by M(B) =
-21. If the same is true in 3C 295 and other clusters of galaxies,
the fraction of galaxies that are observed to be Seyferts depends
critically upon the apparent magnitude limit to which high-quality
spectra can be obtained. Thus, in the most distant clusters, where only
the tip of the luminosity function can be observed, a relatively high
fraction of the blue galaxies for which spectra are obtained would be
expected to be Seyfert galaxies. Among relatively bright field galaxies,
many Seyferts have been overlooked in previous spectral surveys, and
the same may be true in clusters of galaxies. The spectral data must
be published and discussed as functions of absolute magnitude.
Title: Active galactic nuclei.
Authors: Osterbrock, D. E.
Bibcode: 1984QJRAS..25....1O
Altcode:
Observational evidence of the structure of active galactic nuclei,
and the physical conditions in them, is reviewed, with particular
emphasis on optical data. The importance of photoionization by
high-energy photons is stressed. Dust seems to play a considerable
role. X-ray measurements have added greatly to our knowledge of these
objects. There are several indications of a tipped, cylindrically
symmetric, disc-like structure rather than a spherically symmetric
structure. The velocity field is an important constraint that must be
predicted by any complete, physical model.
Title: An Analysis of the Narrow-Line Profiles in High Ionization
Seyfert Galaxies
Authors: Osterbrock, D. E.; De Robertis, M. M.
Bibcode: 1984BAAS...16Q.440O
Altcode:
No abstract at ADS
Title: Adonais: The Life of James Edward Keeler and the Early
Development of American Astrophysics, or, Big Science in the 1890s
Authors: Osterbrock, Donald E.
Bibcode: 1984BAAS...16..519O
Altcode: 1984BAAS...16..519D
No abstract at ADS
Title: The spectrum of V348 Sagittarii.
Authors: Dahari, O.; Osterbrock, D. E.
Bibcode: 1984ApJ...277..648D
Altcode:
The unique irregular variable V348 Sgr was observed at various
epochs. The faintest magnitude found was V = 18.4. It shows brightness
changes of delta-V greater than 6.4, which can occur within a few
days. The spectrum is similar at maximum and minimum light, except
for the forbidden lines, which remain at approximately constant
brightness. In addition to the previously known C II and He I emission
lines, a unique Ne I emission-line spectrum was observed. Using a
curve-of-growth analysis, the abundance of C was found to be dominant
in the chromosphere, with enhanced N and Ne abundances. The relation
of this object to the R CrB stars and the Wolf-Rayet central stars
of planetary nebulae is discussed. A model is suggested in which the
original outer H-rich envelope had been expelled, and a final He-shell
flash in the envelope of the remaining core formed a C-rich extended
envelope. Dust clouds between the chromosphere and the H-rich planetary
nebula cause the strong visible-light variations.
Title: James E. Keeler. Pioneer American astrophysicist and the
early development of American astrophysics
Authors: Osterbrock, Donald E.
Bibcode: 1984jekp.book.....O
Altcode: 1984QB36.K37O88....
No abstract at ADS
Title: Obituary - Shane, Mary-Lea 1897-1983
Authors: Osterbrock, D. E.
Bibcode: 1984JHA....15...74O
Altcode:
No abstract at ADS
Title: Upper limits to O III lambda 5592 and lambda 4594 in Seyfert
galaxies.
Authors: Osterbrock, D. E.; Dahari, O.; Ekberg, J. O.
Bibcode: 1983ApJ...273L..31O
Altcode:
Observational upper limits are given to the strengths of the undetected
emission lines O III 5592 A and forbidden line Ni IX 4594 A in several
well observed Seyfert galaxies. The 5592 A upper limits show that
the O III charge-exchange process does not contribute appreciably to
the observed strength of 4363 A and thus does not appreciably modify
the O III intensity ratio from which the temperature in the O (++)
zone is derived. The 4594 A upper limits are consistent with normal
Ni:Fe abundance ratios of about 0.1 in these objects, but would not
be consistent with Ni:Fe of about 1.
Title: Spectra of Seyfert galaxies and Seyfert galaxy candidates.
Authors: Osterbrock, D. E.; Dahari, O.
Bibcode: 1983ApJ...273..478O
Altcode:
New spectral classifications of a number of Seyfert galaxies, as well
as of other objects that are not but were earlier suspected of being
Seyfert galaxies, are presented. Measured redshifts for all these
objects are also given. Mrk 266 SW and Mrk 1066, two galaxies near the
lower end of the Seyfert 2's and close to Liners (low-ionization nuclear
emission-line regions), are studied spectrophotometrically. Their
relative emission-line spectra agree much better with published models
for photoionization by a low-luminosity power-law-like radiation source
than by shock-wave heating. The spectra of Mrk 883 and Mrk 1320, which
are borderline Seyfert galaxies, of Mrk 984, a double emission-line
galaxy, and Mrk 1459, a galaxy photoionized by a hot-star population,
are briefly discussed.
Title: MRK 744 and MRK 1066 : two Seyfert galaxies with strong
absorption-line spectra.
Authors: Goodrich, R. W.; Osterbrock, D. E.
Bibcode: 1983ApJ...269..416G
Altcode:
Spectrophotometric observations of the nuclei of Mrk 744 and Mrk 1066
are reported. A least-squares fitting procedure is used to decompose
the spectra into the galaxy contribution, the power-law featureless
continuum, and the emission-line spectrum. Equivalent widths of the G,
b, and E2 absorption features were measured, and the corresponding
values of the fraction of power-law contribution at 4800 A were
calculated and compared to the least-squares results. The two sets of
measurements agree well, indicating a featureless continuum fraction
at 4800 A, f, of 0.41 + or - 0.08 and a spectral index alpha of 1.0
+ or - 0.1 for Mrk 744, and f = 0.55 + or 0.02, alpha = 2.4 + or -
0.2 for Mrk 1066. It is suggested that Seyfert 1.8 galaxies such as
Mrk 744 as well as Seyfert 1.9 galaxies may be objects in which the
broad-line emitting region is seen nearly edge-on; the effects of
extinction by dust are therefore unusually large.
Title: The Orion Nebula. (Book Reviews: Symposium on the Orion Nebula
to Honor Henry Draper)
Authors: Osterbrock, Donald E.
Bibcode: 1983Sci...220..945O
Altcode: 1983Sci...220..945G
No abstract at ADS
Title: Observational Constraints on the Structure of Active Galactic
Nuclei
Authors: Osterbrock, D. E.
Bibcode: 1983BAAS...15..682O
Altcode:
No abstract at ADS
Title: J.E. Keeler's discovery of a gap in the outer part of the
A ring
Authors: Osterbrock, D. E.; Cruikshank, D. P.
Bibcode: 1983Icar...53..165O
Altcode:
In early January 1888, James E. Keeler was one of the first astronomers
to work with the very new Lick Observatory 36-in. refractor. On
January 7 while observing Saturn visually on a night of very fine
seeing, he discovered a narrow, dark "division" in the outer part
of the A ring. Despite repeated attempts, neither Keeler nor any of
the other Lick observers saw this gap again until over a year later,
on March 2, 1889, another night of extremely good seeing. On that
occasion not only Keeler, but also E. S. Holden, J. M. Schaeberle, and
E. E. Barnard all observed "Mr. Keeler's division," as Barnard called
it. It could only be seen using very high magnification with this large
telescope, at a site known to be excellent, on the nights of very best
definition. This gap is not the same as the feature which J. F. Encke
had earlier discovered and described as a low-contrast division nearly
in the middle of the A ring, and had drawn as nearly the same width as
Cassini's division. Later visual observations by B. Lyot and A. Dollfus,
again on nights of fine seeing with large telescopes, showed that
the Encke division is complex. To them, with the best resolution, it
appeared as three wide minima of light, fuzzy, and of low contrast,
with a narrow, well-marked minimum of light at its outer edge. The
outer edge is just where Keeler placed his gap, although he did not
see the low-contrast structure in the Encke division. The images,
with much superior resolution obtained from the Pioneer and Voyager
space probes, show that the Encke division is even more complex than
Lyot and Dollfus realized, but confirm the narrow Keeler feature as
a true gap in the outer part of the A ring.
Title: The Galaxy continuum in the spectrum of Cygnus A.
Authors: Osterbrock, D. E.
Bibcode: 1983PASP...95...12O
Altcode:
It is pointed out that high-dispersion, long-exposure spectral scans
have recently been obtained in an attempt to detect in the nucleus the
Mg I b 5175-A absorption feature, which is the best signal of a galaxy
in this situation. Even though difficult to see because it is between
fairly strong forbidden N I 5199-A and weak forbidden Fe VII 5159-A
emission lines, the Mg I feature is definitely present in the nucleus
of Cyg A. Its equivalent width is about 2.3 A. If the underlying galaxy
possesses an absorption-line spectrum similar to a giant elliptical,
this would correspond to about 0.4 of the optical continuum near 5175
A coming from the galaxy, and 0.6 from the featureless continuum
of the active nucleus. Whereas late-type spirals have weaker Mg
I b absorption, other features, such as Fe II 5269 A, then have a
comparable strength. These features are not seen in Cyg A nucleus
scans. Measurements of a few additional emission-line strengths in
the near infrared spectrum of Cyg A are presented.
Title: Planetary nebulae and Seyfert galaxies - Similarities and
differences.
Authors: Osterbrock, D. E.
Bibcode: 1983IAUS..103..473O
Altcode:
Knowledge gained in the study of planetary nebulae has been,
and can be further, transferred to understanding active galactic
nuclei. Photoionization is the main energy-input mechanism in the
narrow-line regions, and probably although by no means certainly in the
broad-line regions as well. There are many detailed differences because
of the much 'harder' input spectrum in active galactic nuclei, compared
with planetaty nebulae. A tentative model of the gas distribution in
a Seyfert-galaxy nucleus is presented.
Title: Atoms in Astrophysics
Authors: Burke, P. G.; Eissner, W. B.; Hummer, D. G.; Percival, I. C.;
Osterbrock, Donald E.
Bibcode: 1983PhT....36h..67B
Altcode:
No abstract at ADS
Title: Two galaxies with Wolf-rayet features in their spectra.
Authors: Osterbrock, D. E.; Cohen, R. D.
Bibcode: 1982ApJ...261...64O
Altcode:
Spectral scans are presented of two galaxies, NGC 6764 and Mrk 309,
which show the Wolf-Rayet emission band 4650 A in the spectra of their
nuclei. Their spectra are discussed and compared with the spectra
of two previously known dwarf galaxies which show this same feature,
as well as with the spectrum of the H II region NGC 604 in M33. The
numbers of Wolf-Rayet stars in the nuclei of NGC 6764 and Mrk 309
similar to those in the Galaxy, or of supermassive Wolf-Rayet stars
similar to the one which may be present in Dor, are estimated.
Title: Seyfert Galaxies, Planetary Nebulae and H II Regions
Authors: Osterbrock, D. E.
Bibcode: 1982PASP...94..756O
Altcode:
No abstract at ADS
Title: Seyfert Galaxy Spectra and Seyfert Galaxy Models
Authors: Osterbrock, D. E.
Bibcode: 1982BAAS...14..910O
Altcode:
No abstract at ADS
Title: The Quest for More Photons - How Reflectors Supplanted
Refractors as the Monster Telescopes of the Future
Authors: Osterbrock, D. E.
Bibcode: 1982BAAS...14..916O
Altcode:
No abstract at ADS
Title: Keeler's Gap in Saturn's A Ring
Authors: Osterbrock, Donald E.; Cruikshank, Dale P.
Bibcode: 1982S&T....64..123O
Altcode:
No abstract at ADS
Title: J. E. Keeler's Discovery of a Gap in Saturn's A-Ring.
Authors: Osterbrock, D. E.; Cruikshank, D. P.
Bibcode: 1982BAAS...14..715O
Altcode:
No abstract at ADS
Title: Emission-line profiles in Seyfert 1 galaxies.
Authors: Osterbrock, D. E.; Shuder, J. M.
Bibcode: 1982ApJS...49..149O
Altcode:
Observed profiles of H I, He I, and He II emission lines in 19 Seyfert
1 galaxies are presented. The data, reduced to energy units versus
radial velocity, are given in accurate graphical form for comparison
with theoretical models. The profiles are shown as directly observed
and as corrected for the blending effects of other lines. Some
implications of these profiles on current models of active galactic
nuclei are discussed.
Title: On the dynamics of the broad-line gas in Seyfert 1 galaxies
Authors: Tohline, J. E.; Osterbrock, D. E.
Bibcode: 1982ApJ...252L..49T
Altcode:
No correlation is found in nearby Seyfert 1 galaxy analyses between
broad permitted line widths and observed galaxy spiral disk inclination,
suggesting that the lines are not rotationally broadened. It is however,
noted that there remain observational and theoretical grounds for
maintaining that rapidly rotating gas in the nucleus of a spiral galaxy
need not be confined to the same plane as that of the primary disk of
the galaxy. The lack of correlation noted therefore does not preclude
rotation as the primary broadening mechanism, for lines emitted from
the broad-line gas in Seyfert 1 galaxies, and models of nuclear gas
dynamics in active galactic nuclei should allow for possible tilted
orientation of the gas.
Title: Optical spectra of radio-loud and radio-quiet active galactic
nuclei
Authors: Osterbrock, D. E.
Bibcode: 1982IAUS...97..369O
Altcode:
No abstract at ADS
Title: University of California: IV. Lick Observatory, Santa Cruz
Campus. Report.
Authors: Osterbrock, D. E.
Bibcode: 1982BAAS...14...66O
Altcode:
No abstract at ADS
Title: Empirical results from a study of active galactic nuclei.
Authors: Shuder, J. M.; Osterbrock, D. E.
Bibcode: 1981ApJ...250...55S
Altcode:
Spectrophotometric observations are presented for emission-line
galaxies. When combined with previous Lick Observatory measurements,
they are used to deduce criteria that allow the Seyfert 2 phenomena to
be quantitatively isolated from the narrow-emission-line galaxies. These
criteria are based on the finding that galaxies with forbidden line O
III 5007 A/H-beta ratios lower than 3 have emission line widths that
are usually considerably smaller than the widths in galaxies with
forbidden line O III 5007 A/H-beta ratios greater than 3. In addition,
large He II 4686 A/H-beta ratios are consistent with forbidden line
O III 5007 A/H-beta ratios greater than 3. The physical conditions
in the narrow-line regions of Seyfert 1 galaxies are compared with
those in Seyfert 2 galaxies. Significant differences are found for
the temperature-sensitive forbidden line O III ratio, and for the
luminosity of Fe VII forbidden line 6087 A relative to the luminosity
of the low-ionization forbidden lines.
Title: Seyfert galaxies with weak broad H alpha emission lines
Authors: Osterbrock, D. E.
Bibcode: 1981ApJ...249..462O
Altcode:
Spectrophotometric measurements show five galaxies with strong narrow
emission lines combined with weak, broad H-alpha and H-beta components
to have line and continuum spectral properties intermediate between
those of Seyfert 1 and Seyfert 2 galaxies. Because they are closer
to the latter, they are called Seyfert 1.8 and Seyfert 1.9, depending
on the presence of broad H-beta emissions in the scans. The observed
intensity ratios of the broad H-alpha/H-beta emission lines are large
compared with those of typical Seyfert 1 galaxies, suggesting the
importance of dust in the broad-line regions. Narrow-line spectra of
the Seyfert 1.8 and 1.9 are found to have low ionization, implying that
their narrow-line region is reached by few high-energy photons. Emphasis
is placed on the correlation between a strong, featureless continuum
and broad H I emission lines in Seyfert and radio galaxies.
Title: The spectrum of III ZW 77 : an unusual, high-ionization
Seyfert 1 galaxy.
Authors: Osterbrock, D. E.
Bibcode: 1981ApJ...246..696O
Altcode:
An observational study is conducted of the spectrum of III Zw
77. Spectral data were obtained of the galaxy with the image-tube
image-dissector scanner developed by Robinson and Wampler (1972)
and the Cassegrain spectrograph and peripherals developed to match
it by Miller et al. (1976), on the 3 m Shane telescope of the Lick
Observatory. It appears that most of the observed spectral features
observed and measured in III Zw 77 can be understood on the basis of
photoionization by a featureless continuum extending to high energies,
well over 300 eV at least. The most likely interpretation is that the
internal reddening is small and that the temperature in the regions
that produce most of the stronger, narrow emission lines is of order
T approximately 25,000 K. There is a general decrease in internal
velocity dispersion from lines of high ionization to low, probably
indicating a decrease of velocity dispersion with increasing distance
from the ionization source.
Title: Orthogonal Gas Disks in Elliptical, Barred Spiral, and
Seyfert Galaxies
Authors: Tohline, J. E.; Durisen, R. H.; Osterbrock, D. E.
Bibcode: 1981BAAS...13..798T
Altcode:
No abstract at ADS
Title: Galaxy Contributions to the Optical Spectra of Cyg A and
Mrk 744
Authors: Osterbrock, D. E.
Bibcode: 1981BAAS...13..824O
Altcode:
No abstract at ADS
Title: Contributions of James E. Keeler to Planetary Research
Authors: Osterbrock, D. E.
Bibcode: 1981BAAS...13..815O
Altcode:
No abstract at ADS
Title: University of California: IV. Lick Observatory, Santa Cruz
Campus. Report.
Authors: Osterbrock, D. E.
Bibcode: 1981BAAS...13...71O
Altcode:
No abstract at ADS
Title: Observational results on Seyfert and radio galaxies with the
Lick Observatory image tube-image dissector scanner
Authors: Osterbrock, D. E.
Bibcode: 1981raoa.conf...39O
Altcode:
The Lick Observatory image tube-image dissector spectral scanner is
described, emphasizing the ways in which it has been optimized for
production of research results. A survey of optical spectra of radio
and Seyfert galaxies made with this instrument is described, and some
of the main results to date are summarized. An observational model
of an active galaxy nucleus, in which irregular expansion of ionized
gas occurs in a plane, is suggested. Recent optical spectra of OQ
208 equals Mrk 668, a broad-line radio galaxy with a large redshift
difference between its broad and narrow emission lines, are described
and tentatively interpreted.
Title: Optical spectrophotometry of narrow-line radio galaxies
Authors: Cohen, R. D.; Osterbrock, D. E.
Bibcode: 1981ApJ...243...81C
Altcode:
Spectrophotometric measurements are presented of the emission lines
in seven narrow-line radio galaxies. The resulting emission-line
ratios, corrected for interstellar extinction on the basis of the H
I Balmer-line ratios, are combined with previously published results
for other narrow-line radio galaxies and Seyfert 2 spectra. Average
spectra for comparison with theoretical models are listed for all the
narrow-line radio galaxies, for all the Seyfert 2 galaxies, and for
the high-ionization and low-ionization groups separately. Comparison
with published results for Seyfert 2 galaxies confirms the general
similarity of the relative strengths of the stronger emission lines in
the two groups found by Koski (1978), except that small differences
are found in the forbidden Ne III/forbidden O III and forbidden N
II/forbidden O III ratios. Likewise, small but significant differences
in the temperature in the O(2+) zone are found between the average
narrow-line radio galaxy and the average Seyfert 2 galaxy. Suggestions
are given for further theoretical modeling of these objects.
Title: Reply to Luyten's criticism of the Lick Automatic Measuring
Engine.
Authors: Jones, B. F.; Osterbrock, D. E.
Bibcode: 1981PLicO..23.....J
Altcode:
No abstract at ADS
Title: Optical spectrophotometry of narrow-line radio galaxies.
Authors: Cohen, R. D.; Osterbrock, D. E.
Bibcode: 1981LicOB.872....1C
Altcode: 1981LickO.872....1C
No abstract at ADS
Title: Observational Cosmology. (Book Reviews: Objects of High
Redshift)
Authors: Osterbrock, Donald E.
Bibcode: 1980Sci...210.1005O
Altcode: 1980Sci...210.1005A
No abstract at ADS
Title: Physical Characteristics of Ionized Gaseous Nebulae
Authors: Osterbrock, D. E.
Bibcode: 1980srst.coll...99O
Altcode: 1980IAUCo..54...99O; 1979srst.coll...99O; 1979srst.nasa...99O
The high angular resolution and the capability of the space telescope to
observe ultraviolet radiation are discussed in relation to investigating
planetary nebulae. The physical characteristics of planetary nebulae
particulary the abundances of the common light elements, the H2 regions,
the angular size, and the surface brightness are reviewed. Differences
between supernova remants and planetary nebulae and H2 regions are
discussed.
Title: The Spectrum of III Zw 77, an Unusual High-Ionization Seyfert
1 Galaxy
Authors: Osterbrock, D. E.
Bibcode: 1980BAAS...12..810O
Altcode:
No abstract at ADS
Title: Spectrophotometry of a new Seyfert 1 galaxy and of GQ Comae.
Authors: Stoughton, R.; Osterbrock, D. E.
Bibcode: 1980PASP...92..117S
Altcode:
A new Seyfert 1 galaxy has been discovered by its variability on
Lick Proper Motion Survey plates. Spectral observations of it and of
GQ Com (a QSO or N galaxy previously discovered through its optical
variability) with the Lick 3-m telescope and image tube-image dissector
scanner show them to have properties overlapping those of the broad-line
radio galaxies.
Title: University of California: IV. Lick Observatory, Santa Cruz
Campus. Report.
Authors: Osterbrock, D. E.
Bibcode: 1980BAAS...12...60O
Altcode:
No abstract at ADS
Title: Emission-line spectra of active galactic nuclei and quasars
Authors: Osterbrock, D. E.
Bibcode: 1980NYASA.336...22O
Altcode: 1980txra.symp...22O
Recent spectrophotometric observations of radio galaxies, Seyfert
galaxies and quasars are reviewed. The optical emission line spectra
of narrow-line radio galaxies such as Cyg A, with line half-widths
on the order of 500 km/sec, Seyfert galaxies, with line half-widths
either of the same order or considerably greater than those of
the narrow-line radio galaxies, and broad-line radio galaxies are
examined, and implications for the physical conditions of the objects
are indicated. The similarities and differences among radio galaxies
and Seyfert galaxies are summarized, with particular emphasis
on their emission line spectra, and emission line similarities
between low-redshift quasars and Seyfert and radio galaxies are
indicated. The ultraviolet spectra of quasars with large redshifts are
then considered. Finally, an overall model of the physical mechanisms
of Seyfert and radio galaxies and quasars, to the extent that they are
similar to the other objects, is discussed in which photoionization
is the energy input mechanism, and a geometrical model that reproduces
the main observed features of active galactic nuclei is presented.
Title: Spectra of Suspected Seyfert Galaxies
Authors: Hatfield, B. F.; Osterbrock, D. E.
Bibcode: 1980BAAS...12..438H
Altcode:
No abstract at ADS
Title: Spectra of additional predicted and suspected Seyfert galaxies.
Authors: Osterbrock, D. E.; Stoughton, R.
Bibcode: 1980PASP...92R.548O
Altcode:
No abstract at ADS
Title: Book-Review - Astronomers at the Royal Observatory Cape of
Good Hope - a History with Emphasis on the Nineteenth Century
Authors: Warner, B.; Osterbrock, D. E.
Bibcode: 1980JHA....11..214W
Altcode:
No abstract at ADS
Title: Graduate astronomy education in the early days of Lick
Observatory.
Authors: Osterbrock, D. E.
Bibcode: 1980Mercu...9..151O
Altcode:
No abstract at ADS
Title: Astronomy Graduate Education in the Early Days of Lick
Observatory
Authors: Osterbrock, D. E.
Bibcode: 1979BAAS...11..680O
Altcode:
No abstract at ADS
Title: Seyfert Galaxies with Weak Broad Hα Emission Lines
Authors: Osterbrock, D. E.
Bibcode: 1979BAAS...11..637O
Altcode:
No abstract at ADS
Title: Spectrophotometry of a New Seyfert 1 Galaxy and of GQ Comae
Authors: Stoughton, R.; Osterbrock, D. E.
Bibcode: 1979BAAS...11R.637S
Altcode:
No abstract at ADS
Title: The Redshift Difference Between the Broad and Narrow Emission
Lines in OQ 208 = MRK 668 and other Galaxies
Authors: Osterbrock, Donald E.
Bibcode: 1979PASP...91..608O
Altcode:
No abstract at ADS
Title: Ionized gas and dust in active galactic nuclei.
Authors: Osterbrock, D. E.
Bibcode: 1979AJ.....84..901O
Altcode:
Spectrophotometric observations concerning the emission-line spectra of
Seyfert and radio galaxies are reviewed. Differences and similarities
between the optical spectra of narrow-line radio galaxies and Seyfert
2 galaxies are described, along with differences and similarities
between the spectra of broad-line radio galaxies and Seyfert 1
galaxies. Observed correlations between the radio and optical properties
of radio galaxies are examined, and photoionization models for Seyfert
and radio galaxies are considered. Evidence for the presence of dust
in Seyfert galaxies is also discussed.
Title: Interstellar Matter. (Book Reviews: Cosmic Dust. Its Impact
on Astronomy)
Authors: Osterbrock, Donald E.
Bibcode: 1979Sci...205..294O
Altcode: 1979Sci...205..294M
No abstract at ADS
Title: Optical spectra of the nuclei of radio galaxies with radio
jets.
Authors: Miley, G. K.; Osterbrock, D. E.
Bibcode: 1979PASP...91..257M
Altcode:
Emission-line optical spectra have been measured for several radio
galaxies with radio jets, including the giant radio galaxies 3C 236
and NGC 6251. The emission lines in all these objects are relatively
weak and correspond to a lower average degree of ionization than in
typical narrow-line radio galaxies.
Title: The Future of Ground-Based Astronomy - I
Authors: Osterbrock, Donald E.
Bibcode: 1979SAOSR.385..139O
Altcode: 1979mfgb.conf..139O
No abstract at ADS
Title: Optical spectra of N galaxies.
Authors: Osterbrock, D. E.; Grandi, S. A.
Bibcode: 1979ApJ...228L..59O
Altcode:
Optical spectra are described of four N galaxies that are not radio
sources, but that were originally discovered as variable 'stars.' Two
of them have absorption-line spectra; the other two have emission-line
spectra that are similar to the emission-line spectra of broad-line
radio galaxies. Neither of the emission-line N galaxies shows detectable
Fe II emission, a feature that is common in typical Seyfert 1 galaxies
but is absent from the spectra of most broad-line radio galaxies.
Title: Physical characteristics of ionized gaseous nebulae.
Authors: Osterbrock, D. E.
Bibcode: 1979NASCP2111...99O
Altcode:
The author discusses planetary nebulae in some detail, and then
those aspects of H II regions and supernova remnants that differ from
planetary nebulae, outlining the main opportunities for nebular research
with the Space Telescope.
Title: The redshift difference between the broad and narrow emission
lines in OQ 208.
Authors: Osterbrock, D. E.; Cohen, R.
Bibcode: 1979MNRAS.187P..61O
Altcode:
Optical spectra are presented for the radio source OQ208 = Markarian
668, a galaxy with a radio spectrum peaked near 7.9 GHz. Its broad H I
emission lines are redshifted by +0.0094, or 2800 km/s, with respect to
the narrow forbidden lines and narrow components of the H I lines. If
the redshift is gravitational in origin, it corresponds to a very large
mass at the center of the broad-line emitting region. The redshift
of the broad lines with respect to the narrow lines in OQ 208 may be
related to the asymmetry of the broad lines in many Seyfert 1 galaxies,
but is larger in amount.
Title: Lick Observatory Solar Eclipse Expeditions
Authors: Osterbrock, D. E.
Bibcode: 1979AstQ....3...67O
Altcode:
No abstract at ADS
Title: Optical spectra and physical conditions in the nuclei of
Seyfert galaxies, radio galaxies, and quasars.
Authors: Osterbrock, D. E.
Bibcode: 1979agn..book...25O
Altcode:
The Lick Observatory image tube/image dissector spectrograph was used
for a spectrophotometric survey of radio galaxies with emission
lines. The program was designed to provide information on the
emission-line strength and profiles as well as the absorption-line
equivalent widths and the continuous spectra of a large number of
radio galaxies. Attention is given to (1) narrow-line radio galaxies,
(2) broad-line radio galaxies, (3) quasars, (4) Seyfert galaxies, (5)
abundances, (6) photoionization models, (7) Fe II emission, (8) internal
velocities, (9) sizes and masses, (10) dust, and (11) radio properties.
Title: Optical spectra of the nuclei of radio galaxies with radio
jets.
Authors: Miley, G. K.; Osterbrock, D. E.
Bibcode: 1979LicOB.835....1M
Altcode: 1979LickO.835....1M
No abstract at ADS
Title: Ionized gas and dust in active galactic nuclei.
Authors: Osterbrock, D. E.
Bibcode: 1979LicOB.840....1O
Altcode: 1979LickO.840....1O
No abstract at ADS
Title: Optical spectra of N galaxies.
Authors: Osterbrock, D. E.; Grandi, S. A.
Bibcode: 1979LicOB.820....1O
Altcode: 1979LickO.820....1O
No abstract at ADS
Title: University of California: IV. Lick Observatory, Santa Cruz
Campus. Report.
Authors: Osterbrock, D. E.
Bibcode: 1979BAAS...11...64O
Altcode:
No abstract at ADS
Title: Spectra of Suspected Seyfert Galaxies
Authors: Osterbrock, D. E.; Grandi, S. A.; Cohen, R. D.
Bibcode: 1978PASP...90..493O
Altcode:
No abstract at ADS
Title: Spectra of Additional Markarian Galaxies
Authors: Osterbrock, D. E.
Bibcode: 1978BAAS...10..623O
Altcode:
No abstract at ADS
Title: First World Astronomy Meeting in America
Authors: Osterbrock, Donald E.
Bibcode: 1978S&T....56..180O
Altcode:
No abstract at ADS
Title: INVITED PAPER - Ionized Gas and Dust in Active Nuclei of
Galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1978BAAS...10..387O
Altcode:
No abstract at ADS
Title: Optical emission-line spectra of Seyfert galaxies and radio
galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1978PhyS...17..137O
Altcode:
Many radio galaxies have strong emission lines in their optical spectra,
similar to the emission lines in the spectra of Seyfert galaxies. The
range of ionization extends from O I and N I through Ne V and Fe VII
to Fe X concentrations. The emission-line spectra of radio galaxies
divide into two types, narrow-line radio galaxies whose spectra are
indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies
whose spectra are similar to Seyfert 1 galaxies. However on the average
the broad-line radio galaxies have steeper Balmer decrements, stronger
O III and weaker Fe II emission than the Seyfert 1 galaxies, though at
least one Seyfert 1 galaxy not known to be a radio source has a spectrum
very similar to typical broad-line radio galaxies. Intermediate-type
Seyfert galaxies exist that show various mixtures of the Seyfert 1
and Seyfert 2 properties, and the narrow-line or Seyfert 2 property
seems to be strongly correlated with radio emission.
Title: Physical state of the emission-line region.
Authors: Osterbrock, D. E.
Bibcode: 1978PhyS...17..285O
Altcode:
The physical properties of the ionized gas in the active nuclei of
Seyfert and radio galaxies derived from their emission-line spectra, are
reviewed. Mean densities and temperatures in Seyfert 2 and narrow-line
radio galaxies are in the ranges of less than 1000-10,000 per cu cm
and 10,000-20,000 deg respectively, while in the narrow-line regions
of Seyfert 1 and broadline radio galaxies the temperatures are similar
but the densities range up to 1,000,000 per cu cm. In the broad-line
regions the densities are 100,000,000 per cu cm or greater. The
abundances of the elements seem more or less normal. The relative
strengths of the lines approximately match photoionization models with
a power-law input spectrum, including the presence of high-ionization
with forbidden lines such as Fe X and Fe XI along with great strength
of neutral and low-ionization forbidden lines such as O I, N I, and
S II. The Fe II emission which occurs in most Seyfert 1 galaxies but
is much weaker or absent in broad-line radio galaxies occurs in the
broad-line high-density region.
Title: Optical spectra of radio galaxies.
Authors: Grandi, S. A.; Osterbrock, D. E.
Bibcode: 1978ApJ...220..783G
Altcode:
Based on Lick image-tube-image-dissector scans of 35 radio galaxies
known to have emission lines, a high degree of association is
found between the spectroscopic classification 'broad-line' and
the morphological classification 'N.' Relative line intensities
are presented for nine broad-line radio galaxies (BLRG). These
data, combined with previously published results, illustrate three
spectroscopic differences between BLRG and Seyfert 1 galaxies: BLRG
have much weaker Fe II emission, steeper H-alpha/H-beta ratios, and
larger 5007-A forbidden O III/H-beta ratios than Seyfert 1 galaxies.
Title: Further Links in the California-Wisconsin Axis in American
Astronomy
Authors: Osterbrock, D. E.
Bibcode: 1978BAAS...10..435O
Altcode:
No abstract at ADS
Title: Observational Model of the Ionized Gas in Seyfert and
Radio-Galaxy Nuclei
Authors: Osterbrock, Donald E.
Bibcode: 1978PNAS...75..540O
Altcode:
Equivalent widths of the total emission-line Hβ in Seyfert 1, Seyfert
2, and intermediate-type Seyfert galaxies, expressed in terms of
the featureless continuum, all have approximately the same frequency
distribution. This suggests that the energy-input mechanism to both
the narrow-line, low-density gas and the broad-line, high-density gas
is photoionization by the featureless continuum. The reason for the
weakness of the narrow emission lines in extreme Seyfert 1 galaxies is
then the absorption of most of the ionizing photons in the dense gas
near the central source. The statistics of line widths can be fitted
by a model in which the dense gas has typical rotational velocity 5000
km/sec and typical turbulent velocity 2000 km/sec. A model is proposed
in which the dense gas forms a rotating, turbulent disk with dimension
≈0.1 pc and height/diameter ≈2/5. Seyfert 2 galaxies are objects
with little dense gas, and intermediate-type Seyfert galaxies are
objects in which the dense gas is optically thin to ionizing radiation
at least along the poles. Most radio galaxies have strong narrow
emission lines, suggesting that escape of radio plasma can only occur
where some ionizing photons can also escape from the dense gas. Other
predictions, implications, and tests of this model are discussed.
Title: E. S. Holden - the founder of the A.S.P. and the early days
of the California-Wisconsin astronomical connection.
Authors: Osterbrock, D. E.
Bibcode: 1978Mercu...7..106O
Altcode:
No abstract at ADS
Title: Photoionization models of Seyfert and radio-galaxy nuclei.
Authors: Osterbrock, D. E.
Bibcode: 1978bs...symp..299O
Altcode:
The extent to which the concept of photoionization can be carried over
to the study of Seyfert and radio galaxies is considered. The optical
spectrum of Cyg A is described and shown to be in good qualitative
agreement with both a power-law photoionization model and observations
of the Crab Nebula, which is known to be photoionized by a power-law
spectrum. It is suggested that the observed emission lines in Cyg A and
other narrow-line radio galaxies result from photoionization of the gas
by radiation with a spectrum extending to at least several hundred eV,
most probably an extension of the featureless continuum observed in
the visible spectral region. It is noted that the optical spectra of
Seyfert 2 galaxies and narrow-line radio galaxies are essentially
indistinguishable. Spectra of some broad-line radio galaxies and
Seyfert 1 galaxies are also examined, along with several correlations
between the (optical) spectral properties and radio properties of
radio galaxies.
Title: Optical emission-line spectra of Seyfert galaxies and radio
galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1978LicOB.774....1O
Altcode: 1978LickO.774....1O
No abstract at ADS
Title: Physical state of the emission-line region.
Authors: Osterbrock, D. E.
Bibcode: 1978LicOB.775....1O
Altcode: 1978LickO.775....1O
No abstract at ADS
Title: University of California: IV. Lick Observatory. Report.
Authors: Osterbrock, D. E.
Bibcode: 1978BAAS...10...58O
Altcode:
No abstract at ADS
Title: Optical spectra of radio galaxies.
Authors: Grandi, S. A.; Osterbrock, D. E.
Bibcode: 1978LicOB.783....1G
Altcode: 1978LickO.783....1G
No abstract at ADS
Title: Su-Shu Huang
Authors: Osterbrock, D. E.
Bibcode: 1977AstQ....1..260O
Altcode:
No abstract at ADS
Title: (Abstract) Spectra of Additional Arakelian Galaxies
Authors: Osterbrock, Donald E.
Bibcode: 1977PASP...89..620O
Altcode:
No abstract at ADS
Title: An Observational Model of the Ionized Gas in Seyfert and
Radio-Galaxy Nuclei
Authors: Osterbrock, D. E.
Bibcode: 1977BAAS....9..647O
Altcode:
No abstract at ADS
Title: Spectrophotometry of Seyfert 1 galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1977ApJ...215..733O
Altcode:
Relative emission-line intensities measured from
image-tube/image-dissector spectral scans performed with a resolution
of approximately 10 A are presented for 36 Seyfert 1 galaxies. The
emission-line intensities are linked to the continuum by measuring the
equivalent width of H-beta, the relative intensities for the Seyfert 1
galaxies are compared with those for five broad-line radio galaxies, and
each Seyfert is classified into one of four groups on the basis of the
appearance of its H-beta profile. It is shown that the broad-line radio
galaxies generally have larger H-alpha/H-beta ratios and steeper Balmer
gradients than the Seyferts, that the He I 5876-A and He II 4686-A
lines in the Seyferts have widths comparable to those of the H I lines,
and that the He abundances are approximately normal in most Seyfert 1
and broad-line radio galaxies. Nearly every Seyfert is found to have
measurable Fe II emission, but a wide intensity range is observed.
Title: Emission-line spectra of seven Arakelian galaxies.
Authors: Osterbrock, D. E.; Phillips, M. M.
Bibcode: 1977PASP...89..251O
Altcode:
of the emission-line spectra of seven Arakelian galaxies are given. Two
of the galaxies have very lowexcitation, weak emission lines, and are
definitely not Seyfert galaxies. Two have emission-line spectra which
are similar to M51 and M81, and a third is closer to these objects
than to Seyfert 2's. One galaxy, Akn 79, is a typical Seyfert 2
object, while another, Akn 120, has the spectrum of a typical Seyfert
1. Relative emission-line intensities are given for Akn 120, and the
line profiles of Hfl and Ho are shown to differ sigrifficantly in form
and width. The equivalent width of HP in Akn 120 is very large (190 A),
and is difficult to account for by photoionization alone. Key words:
Seyfert galaxies- spectrophotometry
Title: Spectrophotometry of Seyfert 1 and Broadline Radio Galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1977BAAS....9..296O
Altcode:
No abstract at ADS
Title: The Optical Spectra of Narrow-Line Radio Galaxies
Authors: Costero, Rafael; Osterbrock, Donald E.
Bibcode: 1977ApJ...211..675C
Altcode:
Line and continuum spectrophotometric measurements are presented of the
five narrow-line radio galaxies 3C 98, 3C 178, 3C 192, 3C 327, and PKS
2322-12. All show relatively strong [0 1] and [S ii] emission lines;
3C 98, 3C 192, and 3C 327 also show high-ionization lines such as [Ne v]
and [Fe vii]. All five galaxies have strong late-type stellar absorption
lines in their continuous spectra. Assuming that the H I emission lines
arise by recombination, the measured line ratios can be approximately
corrected for interstellar extinction. The three high-ionization objects
have emission-line spectra similar to Cyg A, and can be reasonably well
fitted by photoionization models with power-law input spectra. The two
lower ionization objects have emissionline spectra similar to M5l and
M8l; models with steeper power-law input spectra should be calculated
and compared with these objects. The continuous integrated-light
spectrum is not so strongly affected by extinction as the gas, which
together with the dust is probably confined to relatively small volumes
in the nuclei of these galaxies. Subject headings: galaxies: nuclei -
galaxies: stellar content - radio sources: general
Title: Physical Conditions in Radio Galaxies and Quasars
Authors: Osterbrock, D. E.
Bibcode: 1977IAUS...74..183O
Altcode:
No abstract at ADS
Title: Spectrophotometry of Seyfert 1 galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1977LicOB.757....1O
Altcode: 1977LickO.757....1O
No abstract at ADS
Title: University of California: IV. Lick Observatory. V. Board of
Studies in Astronomy and Astrophysics. Observatory reports.
Authors: Osterbrock, D. E.; Bodenheimer, P. H.
Bibcode: 1977BAAS....9...58O
Altcode:
No abstract at ADS
Title: The optical spectra of narrow-line radio galaxies.
Authors: Costero, R.; Osterbrock, D. E.
Bibcode: 1977LicOB.740....1C
Altcode: 1977LickO.740....1C
No abstract at ADS
Title: Su-shu Huang
Authors: Osterbrock, D. E.
Bibcode: 1977AstQ....1..261O
Altcode:
No abstract at ADS
Title: Emission-line spectra of seven Arakelian galaxies.
Authors: Osterbrock, D. E.; Phillips, M. M.
Bibcode: 1977LicOB.764....1O
Altcode: 1977LickO.764....1O
No abstract at ADS
Title: Effective Collision Strengths of Quasar Ultraviolet Emission
Lines
Authors: Osterbrock, D. E.; Wallace, R. K.
Bibcode: 1977ApL....19...11O
Altcode:
The best available published collision strengths for excitation of
permitted and semiforbidden emission lines of abundant ions observed or
expected in quasars have been collected and averaged over Maxwellian
velocity distributions. For a few ions for which calculations are not
available, extrapolation along isoelectronic sequences or in principal
quantum number n was used to estimate values. These collision strengths
were used to correct differentially several published photoionization
models of quasars, and the corrected models are compared with published
observational data.
Title: Variation of the spectrum of the Seyfert galaxy NGC 7603.
Authors: Tohline, J. E.; Osterbrock, D. E.
Bibcode: 1976ApJ...210L.117T
Altcode:
No abstract at ADS
Title: Variation of the spectrum of the Seyfert galaxy NGC 7603.
Authors: Tohline, J. E.; Osterbrock, D. E.
Bibcode: 1976PASP...88..615T
Altcode:
No abstract at ADS
Title: Optical Spectra of Radio and Seyfert Galaxies
Authors: Osterbrock, Donald E.
Bibcode: 1976PASP...88..589O
Altcode:
No abstract at ADS
Title: The Radial Velocity of Calar Alto 1
Authors: Grandi, S. A.; Osterbrock, D. E.; Philipps, M. M.
Bibcode: 1976A&A....51..323G
Altcode:
Summary. The radial velocity of Calar Alto 1 was measured and is +4395
km l 160 km l with respect to the center of our Galaxy. It is thus
not a member of the local group. Key words: galaxies - radial velocity
Title: Effective Collision Strengths of Quasar Ultraviolet Emission
Lines.
Authors: Osterbrock, D. E.; Wallace, R. K.
Bibcode: 1976BAAS....8..531O
Altcode:
No abstract at ADS
Title: NGC 4151 and Markarian 6 - two intermediate-type Seyfert
galaxies
Authors: Osterbrock, D. E.; Koski, A. T.
Bibcode: 1976MNRAS.176P..61O
Altcode:
Scans are presented showing there is a continuous transition between
sSeyfert I and Seyfert 2 galaxies, and that NGC 415 I and Markarian 6,
swith Balmerline profiles consisting of sharp components superimposed on
sbroad weak components, are intermediate objects in this classification
sscheme. Relative emission-line intensity measurements of NGC 4151 from
sthese scans are presented and compared with other recent published
sresults. In confirmation of the conclusion of Boksenberg et al., the
sbroad line profiles of H and He do not agree with those predicted
from sthe model of Ptak & Stoner based on charge exchange with
ssuprathermal ions in a gas at rest.
Title: The optical spectra of 3C 227 and other broad-line radio
galaxies.
Authors: Osterbrock, D. E.; Koski, A. T.; Phillips, M. M.
Bibcode: 1976ApJ...206..898O
Altcode:
Measured emission-line profiles, relative line intensities, and
continuum intensities are reported for 3C 227, 3C 382, and 3C 445, and
are compared with previously obtained data for 3C 390.3. The spectra
of these four radio galaxies are found to be remarkably similar in
overall qualitative aspects; all have broad H I and He I emission lines,
similar forbidden-line spectra, and continuous spectra with relatively
weak absorption lines. The most striking features in all four spectra
are the broad Balmer-line emission profiles, which are not the same in
the four galaxies. It is argued that the broad line profiles must result
from the Doppler effect, due to either thermal velocities, mass-motion
velocities, or radial velocities of injected high-energy protons. The
irregularities in the profiles imply that there is a relatively small
number of 'currents', 'streams', or 'clouds', and that thermal Doppler
broadening cannot be the main contributor. Photoionization is assumed
to be the most plausible energy-input mechanism in all four galaxies.
Title: The spectrum of light pollution at Mount Hamilton.
Authors: Osterbrock, D. E.; Walker, M. F.; Koski, A. T.
Bibcode: 1976PASP...88..349O
Altcode:
Observed spectra of the night sky above Lick Observatory are presented,
showing the light pollution due to lights in San Jose and other
communities in the Santa Clara Valley. Spectra of several types of
street lights are shown, and of these the low-pressure sodium lamp would
cause the least additional light pollution if it were adopted for all
future installations. Key words: light pollution - Lick Observatory -
street-lamp spectra
Title: California-Wisconsin Axis in American Astronomy II
Authors: Osterbrock, Donald E.
Bibcode: 1976S&T....51...91O
Altcode:
No abstract at ADS
Title: Variation of the spectrum of the Seyfert galaxy NGC 7603.
Authors: Tohline, J. E.; Osterbrock, D. E.
Bibcode: 1976LicOB.742....1T
Altcode: 1976LickO.742....1T
No abstract at ADS
Title: University of California: IV. Lick Observatory. V. Board of
Studies in Astronomy and Astrophysics. Observatory reports.
Authors: Osterbrock, D. E.; Mathews, W. G.
Bibcode: 1976BAAS....8...46O
Altcode:
No abstract at ADS
Title: Electron Temperature in the Elliptical Galaxy NGC 1052
Authors: Koski, A. T.; Osterbrock, D. E.
Bibcode: 1976ApJ...203L..49K
Altcode:
No abstract at ADS
Title: The peculiar object He 2-467.
Authors: Lutz, J. H.; Lutz, T. E.; Kaler, J. B.; Osterbrock, D. E.;
Gregory, S. A.
Bibcode: 1976ApJ...203..481L
Altcode:
He has been classified as a planetary nebula. However, the spectrum of
this object shows emission lines superposed on the absorption spectrum
of a G-type star. Image tube spectrograph and scanner observations
of the emission and absorption features are presented. The emission
spectrum is unusual in that no forbidden lines are seen, and the
He I singlet to triplet ratios do not agree with recombination
theory. Subject headings: nebulae: planetary - stars: emission-line
Title: Markarian 376: a Seyfert Galaxy with Strong fe II Emission
Authors: Osterbrock, D. E.
Bibcode: 1976ApJ...203..329O
Altcode:
In a spectrophotometric survey of Seyfert galaxies, Markarian 376
was sfound to have strong, broad Fe ii emission features of the
type spreviously identified in two quasars and a few other Seyfert
galaxies. sThe relative intensities of the individual emission lines and
features sin the spectrum of Markarian 376 were measured. The relative
strengths sof the Balmer lines do not agree with recombination theory;
there is sprobably a contribution to the excitation from collisional
excitation sand perhaps self-absorption. The profiles of the H I and
He ilines are sessentially identical with full widths at half-maximum
of approximately s5000 km s - . Weak, narrow forbidden lines are
also present, with widths sof approximately 400 km s `. A reasonable
extrapolation of the observed scontinuous spectrum has more than
enough near-ultraviolet photons in the sregion to produce all the
observed Fe ii emission by resonance sfluorescence. all the Seyfert
1 galaxies observed to date in this survey shave Fe ii emission in
their spectra. Subject headings: galaxies: sindividual - galaxies:
Seyfert - spectrophotometry
Title: Electron temperature in the elliptical galaxy NGC 1052.
Authors: Koski, A. T.; Osterbrock, D. E.
Bibcode: 1976LicOB.718....1K
Altcode: 1976LickO.718....1K
No abstract at ADS
Title: The radial velocity of Calar Alto 1.
Authors: Grandi, S. A.; Osterbrock, D. E.; Phillips, M. M.
Bibcode: 1976LicOB.741....1G
Altcode: 1976LickO.741....1G
No abstract at ADS
Title: The optical spectra of 3C 227 and other broad-line radio
galaxies.
Authors: Osterbrock, D. E.; Koski, A. T.; Phillips, M. M.
Bibcode: 1976LicOB.724....1O
Altcode: 1976LickO.724....1O
No abstract at ADS
Title: California-Wisconsin Axis in American Astronomy I
Authors: Osterbrock, Donald E.
Bibcode: 1976S&T....51....9O
Altcode:
No abstract at ADS
Title: The Optical Emission-Line Spectrum of 3C 120
Authors: Phillips, M. M.; Osterbrock, D. E.
Bibcode: 1975PASP...87..949P
Altcode:
Spectrophotometric measurements are reported of the nuclear region of 3C
120. The relative intensities of the individual emission lines and the
continuous spectrum were measured in the wavelength region AA3346-7065
(in the rest system of 3C 120). The Balmer decrement is quite steep
and may be caused by interstellar extinction of an amount EB - V =
0.50. However, it is more likely that the large decrement is the result
of collisional or self- absorption effects. The observations by Wampler
and Shields, Oke, and Sargent of strong He I and He ii emission lines
are confirmed. The relative strengths of the He I lines are inconsistent
with pure recombination theory and suggest that collisional or radiative
transfer processes are important. The [S ii] ratio F( 6717)/ F(A6731)
= 0.91 corresponds to a mean electron density of Ne (1041T)1/2 = 1.7 x
1 cm-3 in the region of [S ii] emission. The [0 iii] ratio [F(A5007)
+ F(4959)] /F(x4363) = 23.1 (uncorrected for reddening) implies an
electron temperature of 32,5000 K in the low-density limit Ne 0,
and approximately 23,0000 K for a density of 10 cm-3. Broad emission
features of Fe ii are present in the spectrum. In particular, a weak
emission line at x6369 may be identified with an Fe ii transition of
multiplet (40). The profiles of the H i, He I, and He ii lines are
fairly symmetrical, with the full width at half maximum of the H i
and He I lines approximately 2000 km -l, while He ii x4686 appears to
have somewhat wider wings. The narrower forbidden lines have widths of
roughly 300 km -l A comparison of the relative forbidden line strengths
to those of Cygnus A suggests the presence of a rather complicated
distribution of density with degree of ionization in 3C 120. Key words:
Seyfert galaxies - spectrophotometry - radio sources
Title: Spectrophotometry of Seyfert 1 Galaxies
Authors: Osterbrock, D. E.
Bibcode: 1975BAAS....7..516O
Altcode:
No abstract at ADS
Title: Markarian 376 - a Seyfert galaxy with strong Fe II emission.
Authors: Osterbrock, D. E.
Bibcode: 1975PASP...87..507O
Altcode:
No abstract at ADS
Title: Review of Publications: Astrophysics of Gaseous Nebulae
Authors: Osterbrock, Donald E.
Bibcode: 1975JRASC..69..196O
Altcode:
No abstract at ADS
Title: The Optical Emission-Line Spectrum of 3C 120
Authors: Phillips, M. M.; Osterbrock, D. E.
Bibcode: 1975BAAS....7..452P
Altcode:
No abstract at ADS
Title: Electron Temperature of NGC 1052
Authors: Koski, A. T.; Osterbrock, D. E.
Bibcode: 1975BAAS....7..453K
Altcode:
No abstract at ADS
Title: Optical Emission-Line Spectra of 3C 327 and Other Narrow-Line
Radio Galaxies
Authors: Costero, R.; Osterbrock, D. E.
Bibcode: 1975BAAS....7R.452C
Altcode:
No abstract at ADS
Title: Optical Spectra of 3C 227 and Other Broad-Line Radio Galaxies
Authors: Osterbrock, D. E.; Koski, A. T.; Phillips, M. M.
Bibcode: 1975BAAS....7..452O
Altcode:
No abstract at ADS
Title: The Optical Emission-Line Spectrum of Cygnus a
Authors: Osterbrock, Donald E.; Miller, Joseph S.
Bibcode: 1975ApJ...197..535O
Altcode:
Spectrophotometric measurements are reported of the radio galaxy 3C 405
= Cyg A, made using the image- tube image-dissector scanner on the Lick
120-inch (3 m) telescope. The measurements were reduced to energy units
by comparison with scans of standard stars made with the same system
on the same nights. The emission lines and continuum were measured in
the spectral region AA3346-673 1 (in the rest system of Cyg A). The
interstellar extinction was determined from the measured Balmer-line
ratios, assuming a Case B recombination spectrum and the standard
Whitford reddening curve, and the measured line and continuum strengths
were corrected for this extinction. The corrected line strengths are
discussed for the information they contain on the physical conditions
and the energy-input mechanism to the ionized gas. Photoionization
by stars is ruled out by the great strength of [0 1], [N I], and
[S ii]. Shock-wave heating is ruled out by the [0 iii] temperature,
unless a large amount of ultraviolet ionizing radiation is emitted in
the shock. Published calculations of photo- ionization by a synchrotron
spectrum, extending far into the ultraviolet, approximately match the
observed emission-line spectrum. Likewise, the observed Crab Nebula
spectrum approximately matches Cyg A, except for abundance differences,
in agreement with the idea that Cyg A is photoionized by a power-law
spectrum. Subject headings: radio sources - galaxies, individual -
galactic nuclei - spectrophotometry
Title: Broad Balmer Emission Lines in Radio Galaxies
Authors: Osterbrock, D. E.; Koski, A. T.; Phillips, M. M.
Bibcode: 1975ApJ...197L..41O
Altcode:
No abstract at ADS
Title: University of California: IV. Lick Observatory. V. Board of
Studies in Astronomy and Astrophysics. Observatory reports.
Authors: Osterbrock, D. E.; Mathews, W. G.
Bibcode: 1975BAAS....7..301O
Altcode:
No abstract at ADS
Title: Shahbazian 123: a new distant compact group of compact
galaxies.
Authors: Mirzoyan, L. V.; Miller, J. S.; Osterbrock, D. E.
Bibcode: 1975ApJ...196..687M
Altcode:
Image-tube scanner spectrograms were taken of seven objects in two
Shahbazian compact groups of compact objects. The three brightest
objects in Shahbazian 78 are all late-type stars. On the other hand,
three of the brightest objects in Shahbazian 123 are luminous compact
galaxies with z = 0.115, while a fourth is likely also to be a galaxy
in the group. Sabject headings: galaxies, clusters of - redshifts
Title: The optical emission-line spectrum of Cygnus A.
Authors: Osterbrock, D. E.; Miller, J. S.
Bibcode: 1975LicOB.686....1O
Altcode: 1975LickO.686....1O
No abstract at ADS
Title: The optical emission-line spectrum of 3C 120.
Authors: Phillips, M. M.; Osterbrock, D. E.
Bibcode: 1975LicOB.720....1P
Altcode: 1975LickO.720....1P
No abstract at ADS
Title: On the Location of the Extinction in NGC 7027
Authors: Osterbrock, D. E.
Bibcode: 1974PASP...86..609O
Altcode:
Coude spectrograms of NGC 7027 were obtained at sufficiently
high dispersion to resolve the H alpha, H beta, and H gamma line
profiles. Comparison of the blue and red sides shows no differences
that can be attributed to internal extinction by dust within this
planetary nebula.
Title: Spectrophotometry of the Radio Galaxy Cygnus A.
Authors: Osterbrock, D. E.; Miller, J. S.
Bibcode: 1974BAAS....6..342O
Altcode:
No abstract at ADS
Title: University of California Observatory, Santa Cruz,
California. IV. Lick Observatory. V. Board of Studies in Astronomy
and Astrophysics. Observatory reports.
Authors: Osterbrock, D. E.; Mathews, W. G.
Bibcode: 1974BAAS....6..252O
Altcode:
No abstract at ADS
Title: Nebular photometry with an echelle spectrometer: [O III]
line ratios in NGC 1976 and NGC 6853.
Authors: Bohuski, T. J.; Dufour, R. J.; Osterbrock, D. E.
Bibcode: 1974ApJ...188..529B
Altcode:
Results are presented for measurements of the [0 iii] A5OO71A4363
intensity ratio in NGC 1976, NOC 6853, NGC , and several small planetary
nebulae. The temperatures computed from this ratio are typically
12,000 K in NGC 6853 and ,000 K in NUC 1976. In the latter nebula,
temperatures are found to increase with increasing distance from the
Trapezium. Subject headings: nebulae - planetary nebulae
Title: Astrophysics of gaseous nebulae
Authors: Osterbrock, Donald E.
Bibcode: 1974agn..book.....O
Altcode: 1974QB855.O87......
Questions concerning the photoionization equilibrium are explored,
taking into account hydrogen, helium, and heavy elements. The
characteristics of thermal equilibrium are considered along with a
calculation of the emitted spectrum, a comparison of theoretical studies
with observational data, the internal dynamics of gaseous nebulae,
and the H II regions in the galactic context. Aspects regarding the
interstellar dust are investigated, giving attention to interstellar
extinction, dust within H II regions, infrared emission, the survival of
dust particles in an ionized nebula, and the dynamical effects of dust
in nebulae. Other subjects discussed include the space distribution
and kinematics of planetary nebulae, the origin of planetary nebulae
and the evolution of their central stars, questions of mass return
from planetary nebulae, and planetary nebulae in other galaxies.
Title: The Emission-Line Spectrum of N49 . .
Authors: Osterbrock, D. E.; Dufour, R. J.
Bibcode: 1973ApJ...185..441O
Altcode:
Line identifications and photographically determined relative
emission-line intensities are given for N49, a supernova remnant
in the Large Magellanic Cloud. The measured line intensities agree
qualitatively with supernova-remnant models calculated by Cox, and
disagree strongly with measured line intensities in photoionization
nebulae. The measured line intensities of heavier ions not included
in Cox's models agree qualitatively with calculations from simple
approximate extensions of the models. The main features resulting from
the conversion of kinetic energy into heat followed by recombination
and radiative cooling also appear to be observed in the nuclei of many
emissionline galaxies. Subject headings: galaxies - nebulae - nebulae,
individual - supernova remnants
Title: On the Location of the Extinction in NGC 7027.
Authors: Osterbrock, D. E.
Bibcode: 1973BAAS....5..423O
Altcode:
No abstract at ADS
Title: The Emission-Line Spectrum of the Vela X Supernova Remnant
Authors: Osterbrock, D. E.; Costero, R.
Bibcode: 1973ApJ...184L..71O
Altcode:
Photoelectric spectrophotometric measurements of the bright filament A
in Vela X are presented. The previously reported unusually large Ha/H
ratio is not confirmed. The observed spectrum deviates significantly
from the spectra of H ii regions and planetary nebulae, but agrees
qualitatively with the predicted spectra of shock-wave supernova modeis,
in particular with the Cox model with V = 141 km 5-1 Subject headings:
interstellar matter - supernova remnants
Title: Emission-Line Spectra of Supernova Remnants and Galaxies.
Authors: Osterbrock, D. E.
Bibcode: 1973BAAS....5...11O
Altcode:
No abstract at ADS
Title: Washburn Observatory, University of Wisconsin, Madison,
Wisconsin. Observatory report.
Authors: Osterbrock, D. E.
Bibcode: 1973BAAS....5..247O
Altcode:
No abstract at ADS
Title: Introductory report: The origin and evolution of planetary
nebulae.
Authors: Osterbrock, D. E.
Bibcode: 1973LIACo..18..391O
Altcode: 1973MSRSL...5..391O
No abstract at ADS
Title: Relative emission-line intensities in the Vela X nebula.
Authors: Osterbrock, D. E.; Costero, R.
Bibcode: 1972BAAS....4..423O
Altcode:
No abstract at ADS
Title: The emission-line spectrum of N49, a supernova remnant in
the Large Magellanic Cloud.
Authors: Osterbrock, D. E.; Dufour, R. J.
Bibcode: 1972BAAS....4..398O
Altcode:
No abstract at ADS
Title: Washburn Observatory, University of Wisconsin, Madison,
Wisconsin. Observatory report.
Authors: Osterbrock, D. E.
Bibcode: 1972BAAS....4..193O
Altcode:
No abstract at ADS
Title: Editorial
Authors: Osterbrock, Donald E.
Bibcode: 1971ApJ...169L...1O
Altcode:
No abstract at ADS
Title: Washburn Observatory, University of Wisconsin, Madison,
Wisconsin. Report 1969-1970.
Authors: Osterbrock, D. E.
Bibcode: 1971BAAS....3..217O
Altcode:
No abstract at ADS
Title: Collision Strengths for Ultraviolet Emission Lines in Quasars
Authors: Osterbrock, D. E.
Bibcode: 1971BAAS....3S..25O
Altcode:
No abstract at ADS
Title: Interstellar Matter and Planetary Nebulae (Matière
Interstellaire et Nébuleuses P1anétaires)
Authors: Osterbrock, D. E.
Bibcode: 1971IAUTB..14..203O
Altcode:
No abstract at ADS
Title: Physical Conditions in the Active Nuclei of Galaxies and
Quasi-Stellar Objects Deduced from Line Spectra
Authors: Osterbrock, D. E.
Bibcode: 1971swng.conf..151O
Altcode:
No abstract at ADS
Title: Line and continuum problems in gaseous nebulae.
Authors: Osterbrock, D. E.
Bibcode: 1971JQSRT..11..623O
Altcode:
No abstract at ADS
Title: Helium in the universe. Joint discussion during the XIVth
general assembly of the IAU, Brighton 1970.
Authors: Mathis, J. S.; Osterbrock, D. E.
Bibcode: 1971HiA.....2..245M
Altcode:
No abstract at ADS
Title: Helium in the universe
Authors: Mathis, J. S.; Osterbrock, D. E.
Bibcode: 1971heun.conf.....M
Altcode:
No abstract at ADS
Title: Opening Remarks at Joint Discussion on the Helium in the
Universe
Authors: Osterbrock, D. E.
Bibcode: 1971HiA.....2..247O
Altcode:
No abstract at ADS
Title: Abundances of the Elements in Caseous Nebulae
Authors: Osterbrock, D. E.
Bibcode: 1970QJRAS..11..199O
Altcode:
No abstract at ADS
Title: On the Forbidden Emission Lines of Iron in Seyfert Galaxies
Authors: Nussbaumer, H.; Osterbrock, D. E.
Bibcode: 1970ApJ...161..811N
Altcode:
The excitation of the [Fe vr ], [Fe x], and [FE xivj emission lines
in Seyfert galaxies is discussed, with special reference to the
interpretation of the strengths of these lines in NGC 4151. The [Fe vIr]
lines probably arise in the same regions as the [Ne vi lines. Newly
calculated collision strengths for [Fe v j are presented, and they are
used to find the relative Fe abundance in NGC 4151, approximately N(Fe)/
N(H) = 1.4 X 10- , with an uncertainty of approximately a factor of
2. The [Fe xi and [Fe xivi lines may arise in a high-temperature gas, as
Oke and Sargent suggested. On this model the amount of hightemperature
gas is calculated by using published collision strengths for [Fe
xlvi and published plus estimated collision strengths for [Fe xi. The
radiation from this high-temperature gas, if it exists, is energetically
sufficient to photoionize much of the "cool" gas in which the other
observed emission lines are emitted. Thus the hot gas may be the primary
source of photoionization. It may be heated by collisions between
clouds moving with velocities corresponding to the observed line widths.
Title: Excitation of C III] λ 1909 and Other Semiforbidden Emission
Lines in QSOs and Nebulae
Authors: Osterbrock, D. E.
Bibcode: 1970ApJ...160...25O
Altcode:
Newly calculated collision strengths for 2s2 of C+2 and other
isoelectronic ions are integrated over a Maxwellian distribution
to give effective collision strengths. The fraction of excitations
leading to emission of a line photon is calculated in various density
ranges. The possibility of determinin electron densities in the range
cm-i from the relative strengths of the two components ? is pointed out.
Title: Emission-Line Profiles in the Planetary Nebula IC 418
Authors: Osterbrock, D. E.
Bibcode: 1970ApJ...159..823O
Altcode:
Measurements are presented of II i, [N iii, and [0 irij emission-line
profiles at the center of IC 418. The observed profiles are in
qualitative agreement with published theoretical models of expanding
planetary nebulae. However, detailed comparison shows discrepancies,
particularly in the overlap of the [0 iii] and [N ii] distribution
functions of the emission coefficient, which indicate important
deviations from spherical symmetry.
Title: Excitation of semi-forbidden 2s2 1S-2s2p
3P lines observed in quasars and nebulae
Authors: Osterbrock, D. E.
Bibcode: 1970JPhB....3..149O
Altcode:
No abstract at ADS
Title: Interstellar matter and planetary nebulae.
Authors: Osterbrock, D. E.
Bibcode: 1970IAUTA..14..387O
Altcode:
No abstract at ADS
Title: Calculated [Fe X] and [Fe XIV] Line Strengths in a
Seyfert-Galaxy Model
Authors: Osterbrock, D. E.
Bibcode: 1969BAAS....1R.357O
Altcode:
No abstract at ADS
Title: On the Classification of the Forms and the Stellar Content
of Galaxies
Authors: Morgan, W. W.; Osterbrock, D. E.
Bibcode: 1969AJ.....74..515M
Altcode:
Three principal categories of giant galaxies are defined in terms of
their stellar population: (1) the Orion category (some irregulars),
rich in H ii regions, giant blue stars, and a high gas density; (2) the
Intermediate (giant spirals similar to NGC 5194 and 4321), absorption
spectral types of class F, together with a high degree of compositeness;
(3) the Amorphous (nuclear regions of centrally condensed spirals like
M3 1, and the entire main bodies of the giant ellipticals), spectral
types near KO in the blue and violet regions-to- gether with giant
spectroscopic characteristics. A category of "Combination Galaxies"
is defined in terms of a marked difference between the absorption
spectral type of the nuclear region and the main body. The Androrneda
Galaxy is a prototype for this group. It is shown that our own Galaxy
also belongs to this "Corn- bination" category. It seems probable
that the spectrum of the peculiar irregular NGC 5195 is of the weak-
lined variety. In Sec. XI a review is given of the behavior of emission
lines in ordinary galaxies, Seyfert galaxies, and strong radio sources.
Title: Expected Infrared Spectra of Gaseous Nebulae
Authors: Osterbrock, D. E.
Bibcode: 1969RSPTA.264..241O
Altcode:
No abstract at ADS
Title: 1968 December 13 meeting of the Royal Astronomical Society
Authors: Osterbrock, D. E.
Bibcode: 1969Obs....89...45.
Altcode: 1969Obs....89...46O
No abstract at ADS
Title: Forbidden emission lines in galaxies and quasars.
Authors: Osterbrock, D. E.
Bibcode: 1969MSRSL..25..391O
Altcode: 1969tisa.conf..391O
No abstract at ADS
Title: Calculated [Fe X] and [Fe XIV] Line Strengths in a Seyfert
Galaxy Model
Authors: Osterbrock, D. E.
Bibcode: 1969ApL.....4...57O
Altcode:
No abstract at ADS
Title: 45. Forbidden Emission Lines in Galaxies and Quasars,
Introductory Report
Authors: Osterbrock, D. E.
Bibcode: 1969LIACo..15..391O
Altcode: 1969MSRSL..17..391O
No abstract at ADS
Title: Proceedings of the Conference on Seyfert Galaxies and Related
Objects: 46. Concluding Remarks: Spectroscopic Problems
Authors: Osterbrock, D. E.
Bibcode: 1968AJ.....73..916O
Altcode:
No abstract at ADS
Title: Proceedings of the Conference on Seyfert Galaxies and Related
Objects: 39. Calculated Balmer Decrements for Radiative Excitation
by Power-Law Spectra
Authors: Osterbrock, D. E.
Bibcode: 1968AJ.....73..904O
Altcode:
No abstract at ADS
Title: Planetary nebulae, proceedings from IAU Symposium no. 34.
Authors: Osterbrock, Donald E.; O'dell, Charles Robert
Bibcode: 1968IAUS...34.....O
Altcode:
No abstract at ADS
Title: Physical Processes
Authors: Osterbrock, D. E.
Bibcode: 1968IAUS...34..441O
Altcode:
No abstract at ADS
Title: Interstellar ionized hydrogen. Symposium, Charlottesville,
1967 Dec. 8, 11.
Authors: Terzian, Y.; Osterbrock, D.; Westerhout, G.
Bibcode: 1968iihs.book.....T
Altcode:
No abstract at ADS
Title: Expected infrared spectra of gaseous nebulae.
Authors: Osterbrock, D. E.
Bibcode: 1968RSPTA.264..241O
Altcode:
No abstract at ADS
Title: Emission-Line Profiles in Planetary Nebulae
Authors: Osterbrock, D. E.
Bibcode: 1968IAUS...34..267O
Altcode:
No abstract at ADS
Title: Concluding Remarks I, Optical Observations
Authors: Osterbrock, Donald E.
Bibcode: 1968iih..conf..765O
Altcode:
No abstract at ADS
Title: Diffuse Nebulae
Authors: Osterbrock, Donald E.
Bibcode: 1967PASP...79..523O
Altcode:
No abstract at ADS
Title: Washburn Observatory Report.
Authors: Osterbrock, D. E.
Bibcode: 1967AJ.....72.1152O
Altcode:
No abstract at ADS
Title: Emission-Line Profiles in Planetary Nebulae
Authors: Osterbrock, D. E.; Miller, J. S.; Weedman, D. W.
Bibcode: 1966ApJ...145..697O
Altcode:
Measurements are presented of H I, He ii, [0 iii], and [N ii]
emission-line profiles in several bright planetary nebulae. The lines
are wider than the expected thermal Doppler widths, which indicates
that there are significant mass motions within planetary nebulae. These
observationally determined profiles may be used to test the predictions
of physical models of expanding planetary nebulae. Only a few such
models exist at present, all extremely simplified, but comparison
with assumed samp]e models shows that the distribution of emission
with radial velocity must have a fairly well-defined peak.
Title: Excitation of the Optical Emission Lines in Quasi-Stellar
Radio Sources
Authors: Osterbrock, Donald E.; Parker, Robert A. R.
Bibcode: 1966ApJ...143..268O
Altcode:
No abstract at ADS
Title: Mass Loss in the Planetary Nebula Stage
Authors: Osterbrock, D. E.
Bibcode: 1966stev.conf..381O
Altcode:
No abstract at ADS
Title: Temperature in H II Regions and Planetary Nebulae.
Authors: Osterbrock, Donald E.
Bibcode: 1965ApJ...142.1423O
Altcode:
Collision strengths are found for fine-structure transitions in the 2p
and 2p5 ions N++, O+++, and Ne+ by the quantum-defect method. Collision
strengths are also estimated by a scaling procedure for the 2p2 and
2p4 ions N+, Ne++, Ne++++, and Mg++++. The importance of collisional
de-excitation of the fine-structure levels in reducing the radiative
cooling of gaseous nebulae is quantitatively calculated. The cooling
rates for H ii regions and planetary nebulae are calculated using
these collision strengths and are shown to be in approximate agreement
with observed temperatures in planetary nebulae and the center of the
Orion Nebula.
Title: Studies in Spectral Classification. III. The H-R Diagrams of
NGC 2244 and NGC 2264.
Authors: Morgan, W. W.; Hiltner, W. A.; Neff, J. S.; Garrison, R.;
Osterbrock, D. E.
Bibcode: 1965ApJ...142..974M
Altcode:
New, more accurate, spectral types on the MK system have been
determined for the brighter stars in the clusters NGC 2244 and NGC
2264. The resulting H-R diagrams indicate that the two clusters-and
their accompanying complexes of gas and dust-are located at similar
distances from the Sun-around 800 pc. The reduction in the measured
distance for NGC 2244 is due principally to the use of a high ratio
(6) to total of selective absorption, in accordance with a recent
determination of H. L. Johnson.
Title: Radio-Frequency Optical Depths of Planetary Nebulae.
Authors: Osterbrock, Donald E.
Bibcode: 1965ApJ...141.1285O
Altcode:
No abstract at ADS
Title: Physical Conditions in the Nucleus of the Seyfert Galaxy
NGC 1068.
Authors: Osterbrock, Donald E.; Parker, Robert A. R.
Bibcode: 1965ApJ...141..892O
Altcode:
Photographic spectrophotometric measurements have been made of the
emission lines of the nucleus of the Seyfert galaxy NGC 1068 in order
to identify the mechanism by which excitation and ionization energy
is supplied to the gas. The absolute calibration was provided by
measurements with the same equipment of standard planetary nebulae with
known fluxes. The observational result is thus a table of relative line
strengths (in energy units) over the wavelength interval X 3346-7330. In
addition the total flux (in energy units) in the strong [0 iii] X 5007
line was measured photoelectrically, as well as the continuum flux in
the near ultraviolet. The Balmer gradient is steeper than expected for
either a pure recombination spectrum or a thermalcollisional spectrum
with T> 8000 K. The electron temperatures indicated by [0 iii]
and [N ii] lines show that the ionization is not due to collisions
of thermal electrons. The strength of [0 i] and [N 1], and also the
absence of the Bowen fluorescent lines of 0 iii indicate there is a
substantial amount of neutral gas mixed in with the ionized gas and,
therefore, that the ionization mechanism is not completely ultraviolet
light. Thus a considerable part of the ionization is probably due to
fast protons. The fastest protons would have to have energy about 25
MeV for their ranges to be large enough to excite the entire nucleus if
they come from a single source, but the high4onization lines (such as
[Fe x]) that would be expected to result from such fast protons are
not observed The observed velocities of the gas correspond to energies
ranging up to 25 KeV for protons, sufficient to produce [Ne v] and
[Fe vii] which are in fact observed. Thus it is likely that frequent
collisions between high-velocity clouds produce a large part of the
observed ionization. The observed synchrotron spectrum, extrapolated
to the ultraviolet, does not contain sufficient highenergy photons
to explain the observed ionization. If the proton energy spectrum is
sufficiently steep to low energies, the collisions tend to populate the
2s and 2p states of neutral hydrogen by resonance collisions, which in
turn leads to self-absorption of the Balmer emission lines and strong
emission of Lyman a and the 2-photon continuum by the nucleus.
Title: C_{2} Swan Bands in Comets.
Authors: Stockhausen, Ralph E.; Osterbrock, Donald E.
Bibcode: 1965ApJ...141..287S
Altcode:
The relative populations of the vibrational levels of the X 211 and
A ll electronic levels are calculated assuming the fluorescence
mechanism. Pure vibrational transitions are taken into account
by making a rough estimate of the magnetic-dipole transition
probabilities. Both the approximate method, Rosseland's theory of
cycles applied to a three4evel molecule, and the accurate solution
of the equations of tatistical equilibrium for a ten-level molecule
give similar results. The excitation temperatures derived irom these
relative populations agree satisfactorily with the observations of the
Swan bands by McKellar and Climenhaga (1953) for various Sun-comet
distances. Finally, an estimate is made of the infrared radiation,
due to pure vibrational transitions, expected from a bright comet. The
expected amount of radiation is small and will be difficult to detect.
Title: Radio-Frequency Optical Depths of Planetary Nebulae.
Authors: Osterbrock, Donald E.
Bibcode: 1965AJ.....70T.328O
Altcode:
Measurements of radio4requency radiation from planetary nebulae at
750 and 1410 Mc/sec made by Menon and Terzian (to be published) are
analyzed in terms of simple physical models of the nebulae. Menon and
Terzian's measurements were made relative to 3C71, and their energy
calibration thus depends on its spectrum, and should be revised slightly
to agree with its spectral index as newly determined by Kellerman. This
correction to the calibration is also indicated by the fact that with
the previous calibration NGC 7027, which is optically very thick,
has a steeper spectral slope than a black- body. Comparison of the
observed fluxes at the two frequencies enables the optical depth of
each observed planetary to be determined, relatively independently
of the density, temperature, and distance. The derived optical depths
at 1400 Mc/sec are as follows: NGC 6720 0.1 NGC 6543 0.9 NGC 6853 0.2
IC 418 >0.9 NGC 7662 0.2 NGC 7027 ~20. NGC 7009 0.5 These optical
depths are mostly in approximate agreement with expected values derived
from optical- frequency measurements of the planetary nebulae. However,
the radio-frequency optical depth of NGC 7027 is larger than expected,
and sets it apart from the other planetaries. There is also other
evidence from optical-frequency observations that this nebula is a
different type of object from the typical planetary nebulae.
Title: Physical Conditions in the Nucleus of the Seyfert Galaxy
NGC 1068.
Authors: Osterbrock, D. E.; Parker, R. A. R.
Bibcode: 1964AJ.....69..554O
Altcode:
Photographic spectrophotometric measurements have been made of the
emission lines of the nucleus of the Seyfert galaxy NGC 1068 in
order to identify the mechanism by which excitation and ionization
energy is supplied to the gas. The absolute calibration was provided
by measurements with the same equipment of standard planetary
nebulae with known fluxes. The observational result is thus a table
of relative line strengths (in energy units) over the wavelength
interval XX 3346- 7330, together with upper limits to the strengths
of the unobserved lines. The Balmer gradient is steeper than expected
for either a pure recombination, or a thermal-collisional spectrum
with T>~ 80000K. The electron temperatures indicated by [0 iii~
and [N IIJ lines show that the ionization is not due to collisions
of thermal electrons. The strength of [0 I~ and [N IJ, and also the
absence of the Bowen fluorescent lines of O III indicate there is a
substantial amount of neutral gas mixed in with the ionized gas, and
therefore that the ionization mechanism is not completely ultraviolet
light. Thus, a considerable part of the ionization is probably due to
fast protons. The fastest protons would have to have energy about 25
MeV for their ranges to be large enough to excite the entire nucleus if
they come from a single source, but the high-ionization lines (such as
Fe X) that would be expected to result from these fast protons are not
observed. The observed velocities of the gas correspond to energies
ranging up to 25 keV for protons, sufficient to produce Ne v and
Fe vIl, which are in fact observed. Thus it is likely that frequent
collisions between high-velocity clouds produce part of the energy,
and ultraviolet synchrotron radiation may be responsible for the rest.
Title: Planetary Nebulae
Authors: Osterbrock, Donald E.
Bibcode: 1964ARA&A...2...95O
Altcode:
No abstract at ADS
Title: Balmer-Line Ratios in Planetary Nebulae.
Authors: Osterbrock, D. E.; Capriotti, E. R.; Bautz, L. P.
Bibcode: 1963ApJ...138...62O
Altcode:
Photoelectric observations of relative fluxes in Ha, H , and H of
ten plenatary nebulae, calibrated by measurements of stars with known
continuous spectra, are presented. The measured line ratios are compared
with the recombination theory, modified by interstellar reddening. They
approximately agree with this theory, but the disagreement is larger
than the uncertainty of the measurements, unless there is an undetected
systematic error in the calibration. The measured line ratios do not
show the deviations from the recombination spectrum that would result
from self-absorption of the Balmer lines within the nebulae.
Title: Expected ultraviolet emission spectrum of a gaseous nebula
Authors: Osterbrock, D. E.
Bibcode: 1963P&SS...11..621O
Altcode:
The nebular emission lines expected to be observable in the
satellite ultraviolet are quantitatively discussed. The strengths
of the collisionally excited lines depend on the temperature, on
excitation potentials and abundances which are known and on collision
strengths, which in some cases are known and in other cases are
calculated or else estimated on the basis of the limit theorem. The
strengths of the recombination lines are estimated from available
hydrogen-like computations, and except for He II are generally small in
comparison with the collisionally excited lines except at the shortest
wavelengths. The expected resonance-fluorescence lines and the expected
continua are also briefly discussed.
Title: Emission-Band and Continuum Photometry of Comet Seki
Authors: O'Dell, C. R.; Osterbrock, D. E.
Bibcode: 1962PASP...74..408O
Altcode:
No abstract at ADS
Title: On Para-and Orthohydrogen Molecules in Interstellar Space.
Authors: Osterbrock, D. E.
Bibcode: 1962ApJ...136..359O
Altcode:
The relative amounts of para- and orthohydrogen in interstellar
space are estimated. These depend on transition probabilities between
successive rotational levels in the ground electronic and vibrational
state of the H1 molecule The probability of the radiative transition 2 H
1 is so much larger than the probability of the quadrupole transition
2 H 0 that nearly every molecule that is excited to the level J =
2 goes down to J = 0 via J = 1 The rates of conversion between para-
and orthohydrogen (and vice versa) by this process are estimated,
and it is shown that, though the equilibrium amount of orthohydrogen
is small, its presence could in principle be detected observationally
by its far-infrared line emission.
Title: Emission-Band and Continuum Photometry of Comet Seki (1961f).
Authors: O'Dell, C. R.; Osterbrock, D. E.
Bibcode: 1962ApJ...136..559O
Altcode:
Measurements of Comet Seki were made through interference filters
centered on the C2 X 4737 sequence and on the continuum near X
4470, through diaphragms of various diameters The measurements were
calibrated in energy units by means of a spectral scan made of the
same region of the comet at the same time as the filter measurements
and by measurements of stars with known energy distributions. The
C2 luminosities measured in this way are fitted to a model density
distribution due to Haser, the numerical parameters of which were
derived from the mean C2 surface-brightness curve for comets published
by Miller The resulting C2 densities in Comet Seki are listed, as well
as the densities in Comet Burnham (1959k) derived in the same way from
earlier measurements of this comet.
Title: The Escape of Resonance-Line Radiation from an Optically
Thick Nebula.
Authors: Osterbrock, Donald E.
Bibcode: 1962ApJ...135..195O
Altcode:
The number of scatterings an average Lyman-a photon undergoes before
it either escapes from a gaseous nebula with large optical depth in the
center of this line or else is absorbed by conversion to the two-photon
continuum is estimated. The treatments according to the hypothesis of
complete redistribution of frequency after scattering and according
to the exact redistribution function are shown by numerical examples
to give equivalent results in the Doppler core, but it is necessary
that the calculations extend to frequencies far enough from the center
of the line that, at the greatest shift considered, the nebula is
optically thin The treatment is extended by an approximate diffusion
theory (in frequency space) to the case in which the nebula is so thick
that it becomes transparent only in the damping wings. For an isolated
nebula the probability that a photon is absorbed by conversion to the
two-photon continuum before it escapes is small for optical depths
of about ro < 1060, but in a real nebula the reflection by any
surrounding H i region may increase the absorption within the nebula.