Author name code: topka
ADS astronomy entries on 2022-09-14
author:"Topka, Kenneth P."
------------------------------------------------------------------------
Title: The Kepler Science Operations Center Pipeline: An Overview
of Science Processing and Data Products
Authors: Jenkins, Jon Michael; Bryson, S. T.; Batalha, N. M.; Caldwell,
D. A.; Borucki, W. J.; Koch, D. G.; Chandrasekaran, H.; Quintana,
E. V.; Allen, C. L.; Pletcher, D. P.; Klaus, T.; Middour, C.; Girouard,
F.; Wohler, W.; Cote, M.; McCauliff, S.; Bhavsar, P.; Topka, K.
Bibcode: 2007AAS...21113517J
Altcode: 2007BAAS...39..975J
The Kepler Mission is designed to discover and characterize the
frequency of Earth-size planets in the habitable zone of solar-like
stars by observing 100,000 main-sequence stars in a 100 square degree
field of view (FOV) for at least 3.5 years. The Kepler photometer will
collect and transmit pixels of interest for target stars and associated
collateral data which are received and processed by the Kepler Science
Operations Center (SOC) located at NASA Ames Research Center. The
data are reduced to produce flux time series for each target star,
which are archived at the Data Management Center (DMC) located at
STScI. Systematic errors are removed from each time series, which and
are then subjected to searches for signatures of transiting planets
and reflected light from close-in giant planets. A series of validation
tests are automatically performed on the resulting threshold-crossing
events to assist the science team in prioritizing the candidates for
follow up observations. Performing this level of processing on
>100,000 stars over a 3.5 year period is a significant challenge. The
SOC Pipeline supports automated scheduling of the data reduction upon
data arrival. We describe each data reduction step from initial pixel
level calibrations to the extraction of photometric time series, to
the detection of planetary signatures. We cover the architecture of
the infrastructure supporting the science operations. The SOC Pipeline
also supports the critical tasks of catalog and target management,
as well as performing automated health and performance monitoring of
the Kepler photometer in flight. Funding for this mission provided
by NASA's Discovery Program Office, SMD.
Title: Validation of Kepler Planet Candidates
Authors: Caldwell, Douglas A.; Batalha, N. M.; Borucki, W. J.; Koch,
D. G.; Chandrasekaran, H.; Jenkins, J. M.; Topka, K. P.; Gautier,
T. N.; Gilliland, R. L.
Bibcode: 2006AAS...20921013C
Altcode: 2006BAAS...38.1189C
The Kepler Mission will be able to detect transiting Earth-size
planets in the habitable zone of 30,000 stars and 1.4 Earth radius
planets around 100,000 stars. Such sensitivity will allow Kepler
to detect hundreds of terrestrial planets if they are common, or
place significant upper limits on their numbers if they are rare. In
addition, Kepler will detect many astrophysical false-positives that
mimic transit signals. Most will be background eclipsing binaries
as much as nine magnitudes fainter than the target star. We expect
1000 background binaries with periods less than 3 days and 275 with
longer periods. We have developed a series of automated tests on each
detection, the results of which are used to decide whether planet
candidates will be passed on for follow-up imaging and spectroscopic
observations. The validation process begins with model planet
and eclipsing binary signal fits to the candidate detections. After
subtracting the best-fit planet model, we search the residual flux
time series for additional transiting planets around the star. This
process is repeated until there are no new candidate detections. The
candidate’s centroid time series is then tested against the model
planet signal(s) in order to eliminate background eclipsing binaries
through the change in photocenter position during the eclipse. For
a 12th magnitude G2 star we can discriminate a binary
mimicking an Earth transit if it is separated from the target star by
a quarter of a pixel or more. Tests are also performed to see if the
candidate signal is detected anomalously in only a single pixel of
the aperture (e.g., a variable bad pixel), or if the signal is seen
in the background estimate, or in any of the engineering data (e.g.,
focal plane temperatures,). Funding for Kepler is provided by
NASA’s Discovery Program.
Title: Quick Look Software for the Kepler Photometer
Authors: Topka, Kenneth; Jenkins, J.; Caldwell, D.; Borucki, W. J.
Bibcode: 2006AAS...20921012T
Altcode: 2006BAAS...38.1189T
Kepler is NASA’s first mission capable of finding extra-solar
terrestrial planets that are Earth-size and smaller. The instrument
includes a high gain antenna that is bolted in a fixed position on
the satellite. Thus, the satellite will be rotated in order to point
the antenna at Earth for transmission, an operation that will occur
approximately once a month. In between Earth pointing communication
with Kepler is also possible using a low gain antenna via X-band,
normally used for up-link of commands and down-link of engineering
data. Some of this band pass is reserved for pixel data as well, making
limited amount of science data available for quick look analysis about
twice a week. Quick look software analyzes instrument health
and performance as soon as possible after the data are obtained using
the pixel data from X-band. The performance assessments are based on
examination of time series data generated by the software, and include
stellar brightness, centroid locations, plate scale, encircled energy,
background flux values, CCD black, smear, and dark current levels,
CCD dynamic range, and attitude solution. A more detailed analysis
will be performed after the monthly down-link of all science data. New
time series analyzed then include cosmic ray hit rate, CCD hot pixel
formation rate, and combined differential photometric precision. All
the metrics calculated for quick look will be reanalyzed at higher
precision and higher time resolution. The Kepler mission is funded
by NASA’s Discovery Program
Title: Properties of the Smallest Solar Magnetic
Elements. II. Observations versus Hot Wall Models of Faculae
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1997ApJ...484..479T
Altcode:
Observations obtained at the Swedish Solar Observatory, La Palma,
using the Lockheed tunable filter, have been used to measure
properties of active region faculae, including contrast from disk
center to near the limb. The data consist of coregistered digital
photometric images of the line-of-sight magnetic field and of the
continuum intensity. The results are related to the structure
of the individual flux tubes comprising faculae in active regions. In
addition to center-limb contrast, the observations reveal a change in
contrast between heliocentric angles of about 45° and 60° related
to the ``turn-on'' of bright faculae. A class of models has been
constructed that describes a facula as an evacuated thin flux tube
with a hot wall and a depressed cool floor (hot wall model). The
hot wall model is very successful in predicting the observations,
including the changes observed between 45° and 60°. The model
predicts that the larger flux tubes comprising active region plage are
micropores with a Wilson depression of 100 km largely independent of
micropore diameter. Their typical diameter is 350-650 km; the largest
ones are about 1200 km across. Bright points are the major component of
active region plages by number, but micropores probably are the major
component by total magnetic flux. Bright active region faculae seen
near the limb are simply micropores viewed from the side, where the hot
wall is visible and the depressed cool floor is not. The temperature
difference between cool floor and hot wall varies from 300 to nearly
500 K, depending on tube diameter and heliocentric angle. These
results have important implications for solar irradiance variations.
Title: Solar Irradiance Variations due to the Quiet Sun Network
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1997SPD....28.0263T
Altcode: 1997BAAS...29..904T
An estimate for the change in total solar irradiance due to quiet sun
network during the 11-year solar cycle is presented. The estimate is
based on measurements of the center-limb contrast function for quiet
sun magnetic elements. These measurements are the result of analysis
of near-simultaneous, co-registered, digital, photometric images of
the photospheric intensity (4300 - 6300 A) and line-of-sight magnetic
field. Images were made with the Lockheed tunable filter instrument at
the Swedish Solar Observatory, La Palma, between 1991 and 1994. The
result is of order 0.1%. The images cover only a tiny fraction of
the surface of the Sun and thus a very large extrapolation is made,
limiting the accuracy of the result. Measurements made by satellite
radiometers indicate that on the time scale of solar activity, the total
solar irradiance is greater at activity maximum than at minimum by about
0.1 to 0.15 %. Our result is consistent with this. Earlier results on
active region plage, using similar data from La Palma, indicate that it
does does not contribute significantly to long-term solar irradiance
variations. This work has been supported by NSF contract ATM-9320353,
by NASA contracts NASW-4612 and NAS8-39747, and by Lockheed IR funds.
Title: Solar Irradiance Variations due to Active Region Faculae
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1995SPD....26..512T
Altcode: 1995BAAS...27..959T
No abstract at ADS
Title: Facular Contrast and Hot Wall Models of Flux Tubes
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1994AAS...185.8606T
Altcode: 1994BAAS...26.1465T
Solar rotation causes features on its surface to be viewed at different
angles. The appearance of active region faculae changes dramatically
with viewing angle. They have minimum contrast at disk center, but
appear bright near the limb. The nature of this center-limb variation
is related to the structure of the individual flux tubes comprising
faculae. One class of models depict a facula as an evacuated flux tube
with hot walls and a depressed cool floor (hot wall model). Another
depicts them as hot clouds, because of internal heating. Both can
explain the observed center-limb variation in contrast. In this paper
we ask whether there are other observable phenomena that can help
differentiate between these models. The observations were obtained at
the Swedish Solar Observatory, La Palma, using the Lockheed tunable
filter. The data consist of co-registered images of line-of-sight
magnetic field and of continuum intensity. The correlation between
strong magnetic field and continuum intensity in active region faculae
shows a remarkable and reproducible change between heliocentric angles
of 50deg and 60deg . These results support the hot wall model, but not
the hot cloud model. Hybrid models in which the flux tube has properties
of both models cannot by ruled out. This work has been supported by
NSF contract ATM-9320353, by NASA contracts NASW-4612 and NAS8-39747,
and by Lockheed IR funds.
Title: Contrast of faculae near the disk center and solar variability
Authors: Lawrence, J. K.; Topka, K. P.; Jones, H. P.
Bibcode: 1993JGR....9818911L
Altcode:
We analyze simultaneous, or near-simultaneous, coregistered, digital,
photometric images of solar photospheric intensity and line-of-sight
magnetic field. Images were made with the Lockheed tunable filter
instrument at the Swedish Solar Observatory, La Palma, with the video
spectra-spectroheliograph system at the San Fernando Observatory and
with the new NASA spectromagnetograph at the National Solar Observatory
at Kitt Peak. We study the disk center contrasts of small magnetic
elements. While active region faculae are dark at disk center quiet
Sun network features are bright. The populations of magnetic field
elements that make up these two kinds of are quite different. Different
contrast center-limb functions must be used when estimating their
irradiance or luminosity contributions. The disk center contrasts of
active region faculae are color dependent and indicate a depth effect
related to the H- opacity of the facular atmosphere. This
result is important for calibration of monochromatic observations
of faculae to bolometric irradiance fluctuations. We emphasize the
value of cooperative observations among installations whose differing
strengths are complementary.
Title: The Quiet Sun Network and Solar Irradiance Variations
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1993BAAS...25R1183T
Altcode:
No abstract at ADS
Title: La Palma Observations During the CoMStOC'92 Campaign
Authors: Shine, R.; Tarbell, T.; Topka, K.; Frank, Z.; Title, A.;
Scharmer, G.
Bibcode: 1993BAAS...25S1223S
Altcode:
No abstract at ADS
Title: Inclination of the Magnetic Lines-of-Force of Quiet Sun Network
Authors: Topka, K. P.; Tarball, T. D.; Title, A. M.; Lawrence, J.
Bibcode: 1993AAS...182.4803T
Altcode: 1993BAAS...25R.879T
Photometric measurements of the continuum contrast of active region
plage, after carefully removing all sunspots and pores, has been
obtained for several years from the Swedish Solar Observatory, La
Palma. More recently, similar measurements have been obtained for
magnetic elements in the network far from active regions. These data
were taken with the Lockheed tunable filter instrument using a CCD
camera. The measurements indicate that at disk center active region
plage is dark (negative contrast: intensity less than the surrounding
quiet sun), while the network is bright. Furthermore, active region
plage rapidly turns bright toward the limb; the network also brightens
but more slowly. We have constructed a simple model that assumes
that the magnetic lines-of-force are approximately vertical in active
region plage, while those in the quiet sun network are inclined at the
photosphere. This model correctly predicts the continuum contrast of
network at disk center, and also its variation from center-to-limb. This
provides evidence that the network is often inclined from vertical by
30 degrees or more. This work was supported by Lockheed IR Funds, by
NASA contracts NAS8-32805 (SOUP), NAS5-26813 (OSL), NAS5-30386 (MDI),
and NAS8-38106 (BSOUP), and NSF contract ATM-8912841.
Title: ``The Active Sun'': Educational Videotapes on Solar Physics
for College Astronomy
Authors: Hurlburt, N.; Title, A.; Tarbell, T.; Frank, Z.; Topka, K.;
Shine, R.
Bibcode: 1993AAS...182.1002H
Altcode: 1993BAAS...25..809H
We present a series of short, educational documentaries on solar
physics aimed at college-level general astronomy courses. These
tapes highlight recent advances in high-resolution solar astronomy
and in theoretical and computational modeling of solar physics
with particular focus on dynamical phenomena. The relevant physical
mechanisms, theoretical interpretations and observational techniques
are discussed. These include granulation, the theory of convection,
five-minute oscillations, sunspots, magnetic fields, seeing and
dopplergrams. VHS tapes are available to researchers and educators
through a variety of distributors. This work supported by Lockheed
Independent Research Funds.
Title: On the Magnetic and Velocity Field Geometry of Simple Sunspots
Authors: Title, Alan M.; Frank, Zoe A.; Shine, Richard A.; Tarbell,
Theodore D.; Topka, Kenneth P.; Scharmer, Goran; Schmidt, Wolfgang
Bibcode: 1993ApJ...403..780T
Altcode:
It is presently shown that a simple sunspot model with azimuthal
variations in inclination, but lacking azimuthal field-strength
variations, is free from azimuthal Lorentz forces. The meridional
currents arising from the inclination variations are parallel to the
field lines, suggesting that a cylindrically symmetric magnetostatic
sunspot model can be perturbed into one with azimuthal variations in
inclination with adjustment of the meridional force balance.
Title: White-light movies of the solar photosphere from the SOUP
instrument on Spacelab 2 (Advances in Space Research 1986)
Authors: Title, A. M.; Tarbell, T. D.; Simon, G. W.; Acton, L.;
Duncan, D.; Ferguson, S.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren,
R.; Morrill, M.; Pope, T.; Reeves, R.; Rehse, R.; Shine, R.; Topka,
K.; Harvey, J.; Leibacher, J.; Livingston, W.; November, L.
Bibcode: 1993inas.book..100T
Altcode:
No abstract at ADS
Title: Properties of the Smallest Solar Magnetic Elements. I. Facular
Contrast near Sun Center
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1992ApJ...396..351T
Altcode:
Measurements are presented which indicate that the continuum intensity
of facular areas in solar active regions, outside sunspots and pores, is
less than that of the quiet sun very near disk center. It is shown that
the observed continuum intensity of faculae at disk center near 5000
A is nearly 3 percent less than that of the quiet sun. The continuum
contrast increases rapidly away from disk center, reaching +2 percent
at 45 deg. The zero-crossing point, where the contrast changes sign,
occurs at 20-degree heliocentric angle. This is contrary to many earlier
observations. The constraint these observations place on the size
of flux tubes depends upon the value of the zero-crossing point. It
is proposed that most of the flux tubes in solar faculae may be very
small, in the range 50-100 km in diameter, and that inclination from
local vertical of about 10 deg at the photosphere is common on the
sun. Footpoints of opposite polarity tend to tilt toward one another.
Title: Comparison of Active Region Facular Contrast Measurements to
Simple Models
Authors: Topka, K. P.; Title, A. M.
Bibcode: 1992AAS...181.8104T
Altcode: 1992BAAS...24.1252T
No abstract at ADS
Title: On the Differences between Plage and Quiet Sun in the Solar
Photosphere
Authors: Title, Alan M.; Topka, Kenneth P.; Tarbell, Theodore D.;
Schmidt, Wolfgang; Balke, Christiaan; Scharmer, Goran
Bibcode: 1992ApJ...393..782T
Altcode:
Time sequences of interleaved observations of the continuum intensity,
longitudinal magnetic field, vertical velocity in the midphotosphere,
and the line-center intensity in Ni I 6768 A were obtained in an
active-region plage and the surrounding relatively field-free area near
disk center. Spacetime Fourier filtering techniques are used to separate
the convective and oscillatory components of the solar atmosphere. The
properties of the photosphere are found to differ qualitatively and
quantitatively between the plage, where the field is 150 G or more,
and its quiet surroundings. The scale of granulation is smaller, the
contrast lower, and the temporal evolution slower in the plage than the
quiet sun. In the plage, the vertical velocity is reduced in amplitude
compared to the quiet sun, and there is little evidence of a granulation
pattern, while in the quiet sun the vertical flow pattern is similar in
size and shape to the underlying granulation pattern in the continuum.
Title: Facular Contrast Near Solar Disk Center and the Inclination
of Magnetic Lines of Force from Local Vertical
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1992AAS...180.4004T
Altcode: 1992BAAS...24..793T
No abstract at ADS
Title: High resolution observations: the state of the art and beyond.
Authors: Title, A.; Tarbell, T.; Shine, R.; Topka, K.; Frank, Z.
Bibcode: 1992ESASP.344....9T
Altcode: 1992spai.rept....9T
Excellent telescopes on excellent sites with fast digital CCD cameras
and special purpose computers allow the collection of broad band images
at just the instants of good seeing. This has resulted in nearly optimal
movies of the solar surface for several hours. When longer exposures
are required for narrowband filtergrams or spectra it is not enough to
capture single images. However, big fast memories allow the collection
of many selected low signal-to-noise ratio images in real time, which
can be summed to achieve the desired signal to noise ratios. Adaptive
optics shows promise of diffraction limited images for limited fields
of view. Nevertheless, groundbased observations will always be limited
in their duration, uniformity, and resolution qualities which are
essential for understanding the development and evolution of small scale
processes. Until there are observations in space we will not be able
to completely understand either the processes in the solar atmosphere
or how processes occurring at different height are interrelated.
Title: Investigation of solar active regions at high resolution
by balloon flights of the solar optical universal polarimeter,
definition phase
Authors: Tarbell, Theodore D.; Topka, Kenneth P.
Bibcode: 1992lock.reptQ....T
Altcode:
The definition phase of a scientific study of active regions on the sun
by balloon flight of a former Spacelab instrument, the Solar Optical
Universal Polarimeter (SOUP) is described. SOUP is an optical telescope
with image stabilization, tunable filter and various cameras. After
the flight phase of the program was cancelled due to budgetary
problems, scientific and engineering studies relevant to future balloon
experiments of this type were completed. High resolution observations
of the sun were obtained using SOUP components at the Swedish Solar
Observatory in the Canary Islands. These were analyzed and published
in studies of solar magnetic fields and active regions. In addition,
testing of low-voltage piezoelectric transducers was performed,
which showed they were appropriate for use in image stabilization on
a balloon.
Title: High Resolution Observations of the Magnetic and Velocity
Field of Simple Sunspots
Authors: Title, Alan M.; Frank, Zoe A.; Shine, Richard A.; Tarbell,
T. D.; Topka, K. P.; Scharmer, Goran; Schmidt, Wolfgang
Bibcode: 1992ASIC..375..195T
Altcode: 1992sto..work..195T
We have observed the disk passage of relatively simple round sunspots
using a narrowband filter and a large format CCD detector and have
created magnetograms, Dopplergrams, and continuum images nearly
simultaneously. In addition the spectral resolution of the filter
allows the construction of 'spectra' for all points in the field of
view. The mean inclination of the magnetic field increases from 45-50
deg to 70-75 deg across the penumbra and there is a fluctuation of the
inclination angle about the mean of about 4 +/- 18 deg. The variation in
inclination is large enough that substantial amounts of magnetic field
are parallel to the solar surface from the mid to outer penumbra. The
Evershed flow tends to occur in the regions where the magnetic field
is horizontal. This suggests that the Evershed flow is confined to the
regions of horizontal fields. We show that a simple sunspot model with
azimuthal variations in inclination but no azimuthal variations of
field strength is free from azimuthal Lorentz forces. The meridional
component of the currents which arise from the azimuthal variation
in inclination are parallel to the field lines. This suggests that a
cylindrically symmetric magnetostatic sunspot model can be perturbed
into one with azimuthal variations in inclination with some adjustment
in the meridional force balance.
Title: Low-Cost Space Missions in Solar Physics or Astrophysics
Using Mass-Produced Spacecraft
Authors: Tarbell, T. D.; Jurcevich, B. K.; Title, A. M.; Topka, K. P.
Bibcode: 1991BAAS...23.1317T
Altcode:
No abstract at ADS
Title: Properties of the Smallest Magnetic Elements on the Sun
Authors: Topka, K. P.; Smith, K. L.; Tarbell, T. D.; Title, A. M.;
Scharmer, G.
Bibcode: 1991BAAS...23.1388T
Altcode:
No abstract at ADS
Title: Power Spectra of Flows and Magnetic Fields in the Solar
Photosphere
Authors: Tarbell, T. D.; Slater, G. L.; Frank, Z. A.; Topka, K. P.;
Scharmer, G.; Schmidt, W.
Bibcode: 1991BAAS...23.1048T
Altcode:
No abstract at ADS
Title: Sunspot Umbral and Penumbral Oscillations in Hα
Authors: Shine, R.; Tarbell, T.; Title, A.; Topka, K.; Frank, Z.;
Smith, K.
Bibcode: 1991BAAS...23.1033S
Altcode:
No abstract at ADS
Title: Stokes Polarimetry of a Sunspot from the Swedish Solar
Observatory at La Palma
Authors: Topka, K. P.; Frank, Z. A.; Tarbell, T. D.; Title, A. M.;
Scharmer, G.
Bibcode: 1991BAAS...23Q1052T
Altcode:
No abstract at ADS
Title: High-resolution observations of the solar granulation.
Authors: Topka, K. P.; Title, A. M.
Bibcode: 1991sia..book..727T
Altcode:
The opportunity to observe the solar surface from space and from
excellent groundbased sites, combined with enhanced digital image
recording and computer technology, has led to improved high-resolution
observations of solar granulation in the last decade. Today, granulation
movies over 1 hr long are available with spatial resolution of nearly
1/3″(=240 km on the solar surface). These new data have modified our
conception of solar granulation by showing it to be a more complicated
combination of different phenomena than was previously appreciated. The
smaller granules, for example, may be the result of the fragmentation
of larger granules due to turbulent small-scale flows. The new data
have been used to detect large-scale horizontal flows on the Sun's
surface, by the direct measurement of the proper motion of granules
during their lifetimes. These new results may also have important
implications for the heating of the solar chromosphere and corona.
Title: Generation of Electric Currents and Waves on Magnetic Flux
Tubes by Horizontal Velocities in the Photosphere (With 1 Figure)
Authors: Tarbell, T. D.; Slater, G. L.; Frank, Z. A.; Shine, R. A.;
Topka, K. P.
Bibcode: 1991mcch.conf...39T
Altcode:
No abstract at ADS
Title: SOUP Observations of Solar Activity
Authors: Shine, R. A.; Scharmer, G.; Tarbell, T. D.; Title, A. M.;
Topka, K. P.
Bibcode: 1991max..conf..295S
Altcode:
No abstract at ADS
Title: Detailed Comparison of Quiet and Magnetic Sun
Authors: Topka, K.; Ferguson, S.; Shine, R.; Tarbell, T.; Title, A.;
Balke, C.; Scharmer, G.; Schmidt, W.
Bibcode: 1990BAAS...22R.879T
Altcode:
No abstract at ADS
Title: Intermittency of Fine Scale Solar Magnetic Fields in the
Photosphere
Authors: Tarbell, T.; Acton, S.; Topka, K.; Title, A.; Schmidt, W.;
Scharmer, G.
Bibcode: 1990BAAS...22..878T
Altcode:
No abstract at ADS
Title: Generation of Waves and Electric Currents on Magnetic Flux
Tubes by Horizontal and Vertical Velocities in the Photosphere
Authors: Frank, Z. A.; Shine, R. A.; Slater, G.; Tarbell, T.; Topka, K.
Bibcode: 1990BAAS...22..878F
Altcode:
No abstract at ADS
Title: Magnetic flux tubes and their relation to continuum and
photospheric features
Authors: Title, A.; Tarbell, T.; Topka, K.; Cauffman, D.; Balke, C.;
Scharmer, G.
Bibcode: 1990GMS....58..171T
Altcode:
An investigation is made of the relationship between photospheric
'filigree' light points, line-center brightness, and magnetic field,
as inferred from sets of individual images and films showing a distinct
difference between two classes of magnetic regions. While in the first
such region the vertical velocity field is average and the magnetic
field is mostly confined in narrow lanes, the granulation pattern
of the second scale is much smaller, the vertical velocity is lower,
and the magnetic field is less compact. Where granulation is normal,
excellent correlation is obtained between bright continuum, line-center,
and magnetic field line structure.
Title: High-Resolution Observations of Emerging Magnetic Fields and
Flux Tubes in Active Region Photosphere
Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Shine, R.; Title, A.;
Topka, K.; Scharmer, G.
Bibcode: 1990IAUS..138..147T
Altcode:
No abstract at ADS
Title: High Resolution Observations of the Photosphere
Authors: Title, A. M.; Shine, R. A.; Tarbell, T. D.; Topka, K. P.;
Scharmer, G. B.
Bibcode: 1990IAUS..138...49T
Altcode:
No abstract at ADS
Title: Intial Results of the Lockheed 1989 La Palma Observing Campaign
Authors: Topka, K.; Frank, Z.; Shine, R.; Smith, K.; Tarbell, T.;
Title, A.; Scharmer, G.
Bibcode: 1989BAAS...21.1111T
Altcode:
No abstract at ADS
Title: High - resolution observations of emerging magnetic flux
Authors: Tarbell, T. D.; Topka, K.; Ferguson, S.; Frank, Z.; Title,
A. M.
Bibcode: 1989hsrs.conf..506T
Altcode:
No abstract at ADS
Title: Variation of granulation properties on a meso-granular scale
Authors: Brandt, P. N.; Ferguson, S.; Scharmer, G. B.; Shine, R. A.;
Tarbell, T. D.; Title, A. M.; Topka, K.
Bibcode: 1989hsrs.conf..473B
Altcode:
No abstract at ADS
Title: Proper Motion and Lifetime of Mesogranules
Authors: Frank, Z.; Muller, R.; Roudier, T.; Vigneau, J.; Shine, R.;
Tarbell, T.; Title, A.; Topka, K.; Simon, G.
Bibcode: 1989BAAS...21..841F
Altcode:
No abstract at ADS
Title: Short Term Evolution of Fine Scale Magnetic Structures
Authors: Topka, K.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.;
Scharmer, G.; Balke, A.
Bibcode: 1989BAAS...21..842T
Altcode:
No abstract at ADS
Title: Investigation of Active Regions at High Resolution by Balloon
Flights of the Solar Optical Universal Polarimeter (SOUP)
Authors: Tarbell, T.; Gilbreth, C.; Shine, R.; Title, A.; Topka, K.;
Wolfson, J.
Bibcode: 1989BAAS...21R.837T
Altcode:
No abstract at ADS
Title: Observations of Running Penumbral Waves
Authors: Shine, R.; Tarbell, T.; Title, A.; Topka, K.; Frank, Z.;
Scharmer, G.
Bibcode: 1989BAAS...21..837S
Altcode:
No abstract at ADS
Title: Details of Large Scale Solar Motions Revealed by Granulation
Test Particles
Authors: Simon, G. W.; November, L. J.; Ferguson, S. H.; Shine, R. A.;
Tarbell, T. D.; Title, A. M.; Topka, K. P.; Zirin, H.
Bibcode: 1989ASIC..263..371S
Altcode: 1989ssg..conf..371S
No abstract at ADS
Title: Statistical Properties of Solar Granulation Derived from the
SOUP Instrument on Spacelab 2
Authors: Title, A. M.; Tarbell, T. D.; Topka, K. P.; Ferguson, S. H.;
Shine, R. A.; SOUP Team
Bibcode: 1989ApJ...336..475T
Altcode:
Computer algorithms and statistical techniques were used to identify,
measure, and quantify the properties of solar granulation derived
from movies collected by the Solar Optical Universal Polarimeter on
Spacelab 2. The results show that there is neither a typical solar
granule nor a typical granule evolution. A granule's evolution is
dependent on local magnetic flux density, its position with respect to
the active region plage, its position in the mesogranulation pattern,
and the evolution of granules in its immediate neighborhood.
Title: Flows, Random Motions and Oscillations in Solar Granulation
Derived from the SOUP Instrument on Spacelab 2
Authors: Title, A. M.; Tarbell, T. D.; Topka, K. P.; Ferguson, S. H.;
Shine, R. A.; SOUP Team
Bibcode: 1989ASIC..263..225T
Altcode: 1989ssg..conf..225T
No abstract at ADS
Title: Magnetoconvection on the solar surface.
Authors: Simon, G. W.; Title, A. M.; Topka, K. P.; Tarbell, T. D.;
Shine, R. A.; Ferguson, S. H.; Zirin, H.
Bibcode: 1989GMS....54...53S
Altcode: 1989sspp.conf...53S
The authors describe and illustrate the first high-resolution
observations of horizontal flows on the solar surface and their relation
to magnetic field structure seen in the Sun's photosphere.
Title: Investigation of active regions at high resolution by balloon
flights of the Solar Optical Universal Polarimeter (SOUP)
Authors: Tarbell, T.; Frank, Z.; Gilbreth, C.; Shine, R.; Title, A.;
Topka, K.; Wolfson, J.
Bibcode: 1989dots.work..310T
Altcode:
SOUP is a versatile, visible-light solar observatory, built for space
or balloon flight. It is designed to study magnetic and velocity
fields in the solar atmosphere with high spatial resolution and
temporal uniformity, which cannot be achieved from the surface of the
earth. The SOUP investigation is carried out by the Lockheed Palo Alto
Research Laboratory, under contract to NASA's Marshall Space Flight
Center. Co-investigators include staff members at a dozen observatories
and universities in the U.S. and Europe. The primary objectives of the
SOUP experiment are: to measure vector magnetic and velocity fields in
the solar atmosphere with much better spatial resolution than can be
achieved from the ground; to study the physical processes that store
magnetic energy in active regions and the conditions that trigger
its release; and to understand how magnetic flux emerges, evolves,
combines, and disappears on spatial scales of 400 to 100,000 km. SOUP
is designed to study intensity, magnetic, and velocity fields in the
photosphere and low chromosphere with 0.5 arcsec resolution, free of
atmospheric disturbances. The instrument includes: a 30 cm Cassegrain
telescope; an active mirror for image stabilization; broadband film
and TV cameras; a birefringent filter, tunable over 5100 to 6600 A
with 0.05 A bandpass; a 35 mm film camera and a digital CCD camera
behind the filter; and a high-speed digital image processor.
Title: High-resolution digital movies of emerging flux and horizontal
flows in active regions on the sun
Authors: Topka, K.; Ferguson, S.; Frank, Z.; Tarbell, T.; Title, A.
Bibcode: 1988fnsm.work..283T
Altcode:
High-resolution observations of active regions in many wavelength bands
obtained at the Vacuum Tower Telescope of NSO/Sunspot (Sacramento Peak)
are presented. The SOUP tunable filter, HRSO 1024 x 1024 CCD camera,
and a sunspot tracker for image stabilization were used. Subarrays of
512 x 512 pixels were processed digitally and recorded on videodisk
in movie format. The movies with 0.5 to 1 arcsecond resolution of
the following simultaneous observations were shown: green continuum,
longitudinal magnetogram, Doppler velocity, Fe I 5576 A line center,
H alpha wings, and H alpha line center. The best set of movies show a
90 x 90 arcsecond field-of-view of an active region at S29, W11. When
viewed at speeds of a few thousand times real-time, the photospheric
movies clearly show the active region fields being distorted by a
remarkable combination of systematic flows and small eruptions of new
flux. Flux emergence is most easily discovered in line center movies:
an elongated dark feature appears first, followed soon after by bright
points at one or both ends. A brief, strong upflow is seen when the
dark feature first appears; downflow in the bright points persists
much longer. The magnetic flux appears to increase gradually over this
extended period. Some of the flux emergence events were studied in
detail, with measurements of horizontal and vertical velocities and
magnetic flux versus time within one footpoint of the loop.
Title: Statistical properties of solar granulation from the SOUP
instrument on Spacelab 2
Authors: Topka, K.; Title, A.; Tarbell, T.; Ferguson, S.; Shine, R.
Bibcode: 1988fnsm.work..294T
Altcode:
The Solar Optical Universal Polarimeter (SOUP) on Spacelab 2 collected
movies of solar granulation completely free from atmospheric blurring,
and are not degraded by pointint jitter (the pointing stability
was 0.003 sec root mean square). The movies illustrate that the
solar five minute oscillation has a major role in the appearance of
solar granulation and that exploding granules are a common feature
of the granule evolution. Using 3-D Fourier filtering techniques
the oscillations were removed and it was demonstrated that the
autocorrelation lifetime of granulation is a factor of two greater
in magnetic field regions than in field-free quiet sun. Horizontal
velocities were measured and flow patterns were observed on the scale of
meso- and super granulation. In quiet regions the mean flow velocity
is 370 m/s while in the magnetic regions it is about 125 m/s. It
was also found that the root mean square (RMS) fluctuating horizonal
velocity field is substantially greater in quiet sun than in strong
magnetic field regions. By superimposing the location of exploding
granules on the average flow maps it was found that they appear almost
exclusively in the center of mesogranulation size flow cells. Because
of the nonuniformity of the distribution of exploding granules, the
evolution of the granulation pattern in mesogranule cell centers and
boundaries differs fundamentally. It is clear from this study there
is neither a typical granule nor a typical granule evolution.
Title: Observations of photospheric magnetic fields and shear flows
in flaring active regions
Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K.
Bibcode: 1988fnsm.work...50T
Altcode:
Horizontal flows in the photosphere and subsurface convection zone move
the footpoints of coronal magnetic field lines. Magnetic energy to power
flares can be stored in the corona if the flows drive the fields far
from the potential configuration. Videodisk movies were shown with 0.5
to 1 arcsecond resolution of the following simultaneous observations:
green continuum, longitudinal magnetogram, Fe I 5576 A line center
(mid-photosphere), H alpha wings, and H alpha line center. The movies
show a 90 x 90 arcsecond field of view of an active region at S29,
W11. When viewed at speeds of a few thousand times real-time, the
photospheric movies clearly show the active region fields being
distorted by a remarkable combination of systematic flows and small
eruptions of new flux. Magnetic bipoles are emerging over a large area,
and the polarities are systematically flowing apart. The horizontal
flows were mapped in detail from the continuum movies, and these may
be used to predict the future evolution of the region. The horizontal
flows are not discernable in H alpha. The H alpha movies strongly
suggest reconnection processes in the fibrils joining opposite
polarities. When viewed in combination with the magnetic movies,
the cause for this evolution is apparent: opposite polarity fields
collide and partially cancel, and the fibrils reconnect above the
surface. This type of reconnection, driven by subphotospheric flows,
complicates the chromospheric and coronal fields, causing visible
braiding and twisting of the fibrils. Some of the transient emission
events in the fibrils and adjacent plage may also be related.
Title: Observations of Granulation in Quiet and Magnetic Sun from
the Swedish Solar Observatory on LaPalma
Authors: Topka, K.; Ferguson, S.; Frank, Z.; Shine, R.; Tarbell, T.;
Title, A.; Wolfson, J.; Scharmer, G.; Brandt, P.
Bibcode: 1988BAAS...20S1010T
Altcode:
No abstract at ADS
Title: Solar Activity and Flare Observations from the Swedish Solar
Observatory on La Palma
Authors: Wolfson, J.; Ferguson, S.; Frank, Z.; Shine, R.; Tarbell,
T.; Title, A.; Topka, K.; Scharmer, G.; Brandt, P.; Gurman, J.
Bibcode: 1988BAAS...20..978W
Altcode:
No abstract at ADS
Title: On the Relation between Photospheric Flow Fields and the
Magnetic Field Distribution on the Solar Surface
Authors: Simon, George W.; Title, A. M.; Topka, K. P.; Tarbell, T. D.;
Shine, R. A.; Ferguson, S. H.; Zirin, H.; SOUP Team
Bibcode: 1988ApJ...327..964S
Altcode:
Using the technique of local correlation tracking on a 28 minute time
sequence of white-light images of solar granulation, the horizontal
flow field on the solar surface is measured. The time series was
obtained by the Solar Optical Universal Polarimeter (SOUP) on Spacelab 2
(Space Shuttle flight 51-F) and is free from atmospheric blurring and
distortion. The SOUP flow fields have been compared with carefully
aligned magnetograms taken over a nine hour period at the Big Bear
Solar Observatory before, during, and after the SOUP images. The flow
field and the magnetic field agree in considerable detail: vectors which
define the flow of the white-light intensity pattern (granulation) point
toward magnetic field regions, magnetic fields surround flow cells, and
magnetic features move along the flow arrows. The projected locations
of free particles ('corks') in the measured flow field congregate at
the same locations where the magnetic field is observed.
Title: Observations of Photospheric Magnetic Fields and Shear Flows
in Flaring Active Regions
Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K.
Bibcode: 1988BAAS...20..744T
Altcode:
No abstract at ADS
Title: High-Resolution Digital Movies of Emerging Flux and Horizontal
Flows in Active Regions on the Sun
Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K.
Bibcode: 1988BAAS...20..680T
Altcode:
No abstract at ADS
Title: Statistical Properties of Solar Granulation from the SOUP
Instrument on Spacelab 2
Authors: Topka, K.; Title, A.; Tarbell, T.; Ferguson, S.; Shine, R.
Bibcode: 1988BAAS...20Q.679T
Altcode:
No abstract at ADS
Title: Variability of solar mesogranulation
Authors: Simon, G. W.; November, L. J.; Acton, L. W.; Ferguson, S. H.;
Shine, R. A.; Tarbell, T. D.; Title, A. M.; Topka, K. P.; Zirin, H.
Bibcode: 1988AdSpR...8g.169S
Altcode: 1988AdSpR...8..169S
From white-light photographs of solar granulation obtained with the
SOUP instrument on Space Shuttle Flight STS-19 we have measured the
motions of granules using local correlation tracking techniques. The
granules are organized into larger-scale structures (mesogranular and
supergranular) which exhibit outflow from upwellings, convergence into
sinks, as well as significant vorticity. Magnetic fields follow these
same flow patterns. We describe these velocity structures, and suggest
that their effect on magnetic field structures may be important to
the solar flare buildup process.
Title: Correlation Lifetimes of Quiet and Magnetic Granulation from
the SOUP Instrument on Spacelab 2
Authors: Title, A.; Tarbell, T.; Topka, K.; Acton, L.; Duncan, D.;
Ferguson, S.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren, R.; Morrill,
M.; Pope, T.; Reeves, R.; Rehse, R.; Shine, R.; Simon, G.; Harvey,
J.; Leibacher, J.; Livingston, W.; November, L.; Zirker, J.
Bibcode: 1988ApL&C..27..141T
Altcode:
The time sequences of diffraction limited granulation images obtained by
the Solar Optical Universal Polarimeter on Spacelab 2 are presented. The
uncorrection autocorrelation limetime in magnetic regions is dominated
by the 5-min oscillation. The removal of this oscillation causes the
autocorrelation lifetime to increase by more than a factor of 2. The
results suggest that a significant fraction of granule lifetimes are
terminated by nearby explosions. Horizontal displacements and transverse
velocities in the intensity field are measured. Lower limits to the
lifetime in the quiet and magnetic sun are set at 440 s and 950 s,
respectively.
Title: The relation between convection flows and magnetic structure
at the solar surface
Authors: Simon, G. W.; November, L. J.; Acton, L. W.; Title, A. M.;
Tarbell, T. D.; Topka, K. P.; Shine, R. A.; Ferguson, S. H.; Weiss,
N. O.; Zirin, H.
Bibcode: 1988AdSpR...8k.133S
Altcode: 1988AdSpR...8..133S
We describe recent results from the comparison of data from the Solar
Optical Universal Polarimeter instrument on Spacelab 2 and magnetograms
from Big Bear Solar Observatory. We show that the Sun's surface velocity
field governs the structure of the observed magnetic field over the
entire solar surface outside sunspots and pores. We attempt to describe
the observed flows by a simple axisymmetric plume model. Finally,
we suggest that these observations may have important implications
for the prediction of solar flares, mass ejections, and coronal heating.
Title: White Light Sunspot Observations from the Solar Optical
Universal Polarimeter on Spacelab-2
Authors: Shine, R. A.; Title, A. M.; Tarbell, T. D.; Topka, K. P.
Bibcode: 1987Sci...238.1264S
Altcode:
The flight of the Solar Optical Universal Polarimeter on Spacelab-2
provided the opportunity for the collection of time sequences of
diffraction-limited (0.5 arc second) solar images with excellent
pointing stability (0.003 arc second) and with freedom from the
distortion that plagues ground-based images. A series of white-light
images of active region 4682 were obtained on 5 August 1985, and
the area containing the sunspot has been analyzed. These data have
been digitally processed to remove noise and to separate waves from
low-velocity material motions. The results include (i) proper motion
measurements of a radial outflow in the photospheric granulation
pattern just outside the penumbra; (ii) discovery of occasional bright
structures (``streakers'') that appear to be ejected outward from the
penumbra; (iii) broad dark ``clouds'' moving outward in the penumbra,
in addition to the well-known bright penumbral grains moving inward;
(iv) apparent extensions and contractions of penumbral filaments over
the photosphere; and (v) observation of a faint bubble or looplike
structure that seems to expand from two bright penumbral filaments
into the photosphere.
Title: High-Resolution CCD Observations of Doppler and Magnetic
Images in the Solar Photosphere
Authors: Tarbell, T. D.; Frank, Z. A.; Morrill, M. E.; Shine, R. A.;
Topka, K. P.; Title, A. M.
Bibcode: 1987BAAS...19.1117T
Altcode:
No abstract at ADS
Title: On the Relation between Magnetic Field Structures and
Granulation
Authors: Title, A. M.; Tarbell, T. D.; Topka, K. P.
Bibcode: 1987ApJ...317..892T
Altcode:
Narrow-band observations of a solar emerging-flux region, obtained
at 525.02 nm with resolution 0.5 arcsec using the Sacramento Peak
vacuum-tower telescope and the Spacelab 2 tunable filter on December
10, 1979, are reported. The data are presented in histograms and
characterized in detail. Magnetic-flux concentrations of 600-1000 G
are found to be located in areas of suppressed downflow near holes or
pores in the granulation pattern, while 100-500-G concentrations occur
in areas with stronger downdrafts, in cell-like structures of diameter
2-5 arcsec, the fields being aligned with dark intergranular lanes. It
is inferred that granulation concentrates the magnetic field in the
downflow lanes (as found in numerical simulations by Nordlund, 1983),
and that the magnetic structures are more diffuse and longer-lasting
than the bright spots; thus bright-point maps are contained in, rather
than equivalent to, magnetic-field maps.
Title: On the Relation Between Large-Scale Granular Flows and
Supergranules and Mesogranules
Authors: Simon, G.; Ferguson, S.; Tarbell, T.; Title, A.; Topka, K.;
November, L.; Zirin, H.
Bibcode: 1987BAAS...19R.935S
Altcode:
No abstract at ADS
Title: Simultaneous Observations of Emerging Flux from the Big Bear
Solar Observatory and the SOUP Instrument on Spacelab 2
Authors: Topka, K.; Ferguson, S.; Title, A.; Tarbell, T.; Zirin, H.;
Simon, G.; November, L.
Bibcode: 1987BAAS...19R.927T
Altcode:
No abstract at ADS
Title: Simultaneous Sunspot Observations from the SOUP Instrument
on Spacelab 2 and the Big Bear Solar Observatory
Authors: Shine, R. A.; Title, A. M.; Topka, K. P.; Tarbell, T. D.;
Zirin, H.
Bibcode: 1987BAAS...19..927S
Altcode:
No abstract at ADS
Title: Exploding and Elongated Granules
Authors: Title, A. M.; Tarbell, T. D.; Ferguson, S. H.; Topka, K. P.
Bibcode: 1987BAAS...19Q.927T
Altcode:
No abstract at ADS
Title: New Ideas About Granulation Based on Data from the Solar
Optical Universal Polarimeter Instrument on Spacelab 2 and Magnetic
Data from Big Bear Solar Observatory
Authors: Title, A. M.; Tarbell, T. D.; Topka, K. P.; Shine, R. A.;
Simon, G. W.; Zirin, H.; SOUP Team
Bibcode: 1987LNP...292..173T
Altcode: 1987ssp..conf..173T
The SOUP flow fields have been compared with carefully aligned
magnetograms taken at the BBSO before, during, and after the SOUP
images. The magnetic field is observed to exist in locations where
either the flow is convergent or on the boundaries of the outflow from
a flow cell center. Streamlines calculated from the flow field agree
very well with the observed motions of the magnetic field in the BBSO
magnetogram movies.
Title: High-Resolution Observations of Changing Magnetic Features
on the Sun
Authors: Topka, K. P.; Tarbell, T. D.; Title, A. M.
Bibcode: 1986ApJ...306..304T
Altcode:
The total magnetic flux present in 28 small isolated unipolar features
that surround an active region has been measured on a well-registered
sequence of high-resolution magnetograms. Seventeen features showed no
changes, but the rest showed changes in measured flux with time that
were much greater than the uncertainty in the flux determination. Two
magnetic features showed evidence for increases in flux with time,
while nine others showed decay. In some cases the decaying features
appear to be canceling with nearby opposite polarity flux, which may
represent the submergence of flux below the photosphere. In others,
the observed decay occurs in regions that are strictly unipolar,
with no observable opposite polarity flux present. Some evidence for
the outward diffusion of flux from a decaying feature in a unipolar
region was found.
Title: Properties of Solar Granulation in Magnetic versus Non-Magnetic
Regions
Authors: Topka, K. P.; Tarbell, T. D.; SOUP Team
Bibcode: 1986BAAS...18..662T
Altcode:
No abstract at ADS
Title: White-light movies of the solar photosphere from the soup
instrument on spacelab 2
Authors: Title, A. M.; Tarbell, T. D.; Simon, G. W.; Acton, L.;
Duncan, D.; Ferguson, S.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren,
R.; Morrill, M.; Pope, T.; Reeves, R.; Rehse, R.; Shine, R.; Topka,
K.; Harvey, J.; Leibacher, J.; Livingston, W.; November, L.
Bibcode: 1986AdSpR...6h.253T
Altcode: 1986AdSpR...6..253T
We present initial results on solar granulation, pores and sunspots
from the white-light films obtained by the Solar Optical Universal
Polarimeter (SOUP) instrument on Spacelab 2. SOUP contains a
30-cm Cassegrain telescope, an active secondary mirror for image
stabilization, and a white-light optical system with 35-mm film
and video cameras. Outputs from the fine guidance servo provided
engineering data on the performance of the ESA Instrument Pointing
System (IPS). Several hours of movies were taken at various
disk and limb positions in quiet and active regions. The images
are diffraction-limited at 0.5 arc second resolution and are, of
course, free of atmospheric seeing and distortion. Properties of the
granulation in magnetic and non-magnetic regions are compared and are
found to differ significantly in size, rate of intensity variation,
and lifetime. In quiet sun on the order of fifty percent of the area
has at least one ``exploding granule'' occurring in it during a 25
minute period. Local correlation tracking has detected several types
of transverse flows, including systematic outflow from the penumbral
boundary of a spot, motion of penumbral filaments, and cellular flow
patterns of supergranular and mesogranular size. Feature tracking has
shown that in quiet sun the average granule fragment has a velocity
of about one kilometer per second.
Title: Association of Small, Bright Photospheric Features with
Magnetic Fields
Authors: Topka, K.; Shine, R.; SOUP Team
Bibcode: 1985BAAS...17..834T
Altcode:
No abstract at ADS
Title: High Resolution Observations of Magnetic Features on the Sun
Authors: Topka, K. P.; Tarbell, T. D.
Bibcode: 1984BAAS...16..991T
Altcode:
No abstract at ADS
Title: High Spatial Resolution Magnetic Observation of an Active
Region
Authors: Topka, K.; Tarbell, T.
Bibcode: 1984ssdp.conf..278T
Altcode:
High spatial resolution magnetograms of an active region reveal
apparent changes in the magnetic flux of small isolated features on
time scales less than 30 minutes. Both flux increases and decreases
are observed, sometimes for a single feature. These changes are seen
in small unipolar magnetic regions with no obvious changes observed
in any nearby opposite polarity features.
Title: The Coordinated Instrument Package for the Solar Optical
Telescope
Authors: Wolfson, C. J.; Tarbell, T. D.; Topka, K. P.; Title, A. M.
Bibcode: 1983BAAS...15R.718W
Altcode:
No abstract at ADS
Title: Scientific Observing Plans for the SOT Coordinated Filtergraph
Spectrograph
Authors: Tarbell, T. D.; Wolfson, C. J.; Topka, K. P.
Bibcode: 1983BAAS...15R.709T
Altcode:
No abstract at ADS
Title: The SOT Video Data System
Authors: Topka, K. P.; Lindgren, R. W.; Duncan, D. W.
Bibcode: 1983BAAS...15Q.709T
Altcode:
No abstract at ADS
Title: On the Disappearance of a Small Sunspot Group
Authors: Wallenhorst, S. G.; Topka, K. P.
Bibcode: 1982SoPh...81...33W
Altcode:
The small sunspot group associated with Hale active region 17694
was observed jointly by the Mount Wilson and the Big Bear Solar
Observatories, through the time of sunspot disappearance. The magnetic
flux from the region was seen to decrease by about 10% per day during
the observing interval. This was accompanied by fragmentation of
the dominant spot as a supergranule network formed. No evidence for
spreading or diffusion of the active region field was found.
Title: Evidence for a Poleward Meridional Flow on the Sun
Authors: Topka, K.; Moore, R.; Labonte, B. J.; Howard, R.
Bibcode: 1982SoPh...79..231T
Altcode:
We define for observational study two subsets of all polar zone
filaments, which we call polemost filaments and polar filament
bands. The behavior of the mean latitude of both the polemost filaments
and the polar filament bands is examined and compared with the evolution
of the polar magnetic field over an activity cycle as recently distilled
by Howard and LaBonte (1981) from the past 13 years of Mt. Wilson
full-disk magnetograms. The magnetic data reveal that the polar
magnetic fields are built up and maintained by the episodic arrival of
discrete f-polarity regions that originate in active region latitudes
and subsequently drift to the poles. After leaving the active-region
latitudes, these unipolar f-polarity regions do not spread equatorward
even though there is less net flux equatorward; this indicates that
the f-polarity regions are carried poleward by a meridional flow,
rather than by diffusion. The polar zone filaments are an independent
tracer which confirms both the episodic polar field formation and the
meridional flow. We find: The mean latitude of the polemost filaments
tracks the boundary of the polar field cap and undergoes an equatorward
dip during each arrival of additional polar field.
Title: A magnitude limited stellar X-ray survey and the F star X-ray
luminosity function.
Authors: Topka, K.; Golub, L.; Gorenstein, P.; Harnden, F. R., Jr.;
Vaiana, G. S.; Avni, Y.; Rosner, R.
Bibcode: 1982ApJ...259..677T
Altcode:
An X-ray survey has been conducted of stars brighter than visual
magnitude 8.5 that have serendipitously fallen into the fields of view
of the Imaging Proportional Counter of the Einstein Observatory. The
survey includes 227 separate 1 x 1 deg fields, containing 274 stars
with a visual magnitude of no more than 8.5 and covering a wide range
of spectral types and luminosity classes. X-ray emission was detected
from 33 stars, and upper limits have been determined for the remainder
of the sample. F type stars dominate the detected sample, and most of
these are shown to be dwarfs. An X-ray luminosity function for dF stars
has been deduced, and reveals that the average 0.2-4.0 keV luminosity
of these stars is around 10 to the 29th erg/sec. Constraints have been
placed on the high luminosity tails and medians of the X-ray luminosity
functions for other types of stars.
Title: Detection of microwave emission from both components of the
red dwarfbinary EQ Peg.
Authors: Topka, K.; Marsh, K. A.
Bibcode: 1982ApJ...254..641T
Altcode:
The detection at 4.9 GHz of the late main sequence binary EQ Pegasi
(dM3.5e + dM4.5e) with the VLA is reported. Both components were
detected, as flux levels of 0.69 mJy and 0.4 mJy, respectively. Thermal
gyroresonance emission from the quiescent coronae of these stars appears
to explain observations of the authors, as it does those of Gary and
Linsky (1981) for chi Ori and UV Ceti, provided coronal magnetic fields
in excess of 300 gauss exist over a region that has a length scale of
at least twice the radii of these stars. Support for this model is
provided by the unlikelihood of both stars flaring simultaneously,
and by the fact that the emission was confined to each star within
the observational uncertainty of a few AU.
Title: Death of a Sunspot
Authors: Topka, K. P.; Wallenhorst, S. G.
Bibcode: 1982BAAS...14..640T
Altcode:
No abstract at ADS
Title: The stellar contribution to the galactic soft X-ray background
Authors: Rosner, R.; Avni, Y.; Bookbinder, J.; Giacconi, R.; Golub,
L.; Harnden, F. R., Jr.; Maxson, C. W.; Topka, K.; Vaiana, G. S.
Bibcode: 1981ApJ...249L...5R
Altcode:
Log N-log S relations for stars are constructed based on median
X-ray luminosities for dF, dG, and dK stars previously reported for
the Einstein Observatory/Center for Astrophysics stellar survey and
on a detailed X-ray luminosity function derived here for dM stars,
and the stellar contribution to the diffuse soft X-ray background is
investigated. The principal results are that stars provide approximately
20% of the soft X-ray background in the 0.28-1.0 keV passband and
therefore contribute significantly to the soft X-ray background in this
energy range (with dM stars constituting the dominant contributing
class), and that the stellar contribution to the diffuse X-ray
background in the 0.15-0.28 keV passband is less than approximately 3%.
Title: Results from an extensive Einstein stellar survey.
Authors: Vaiana, G. S.; Cassinelli, J. P.; Fabbiano, G.; Giacconi,
R.; Golub, L.; Gorenstein, P.; Haisch, B. M.; Harnden, F. R., Jr.;
Johnson, H. M.; Linsky, J. L.; Maxson, C. W.; Mewe, R.; Rosner, R.;
Seward, F.; Topka, K.; Zwaan, C.
Bibcode: 1981ApJ...245..163V
Altcode:
The preliminary results of the Einstein Observatory stellar X-ray survey
are presented. To date, 143 soft X-ray sources have been identified with
stellar counterparts, leaving no doubt that stars in general constitute
a pervasive class of low-luminosity galactic X-ray sources. Stars along
the entire main sequence, of all luminosity classes, pre-main sequence
stars as well as very evolved stars have been detected. Early type
OB stars have X-ray luminosities in the range 10 to the 31st to 10 to
the 34th ergs/s; late type stars show a somewhat lower range of X-ray
emission levels, from 10 to the 26th to 10 to the 31st ergs/s. Late type
main-sequence stars show little dependence of X-ray emission levels upon
stellar effective temperature; similarly, the observations suggest weak,
if any, dependence of X-ray luminosity upon effective gravity. Instead,
the data show a broad range of emission levels (about three orders of
magnitude) throughout the main sequence later than F0.
Title: Absolute Light Curves of Solar Flares in Hα
Authors: Topka, K.; Hurford, G. J.
Bibcode: 1981BAAS...13..890T
Altcode:
No abstract at ADS
Title: The Magnetic Evolution of Active Regions: Disappearance of
Photospheric Magnetic Flux
Authors: Topka, K.; Moore, R. L.
Bibcode: 1980BAAS...12..792T
Altcode:
No abstract at ADS
Title: Polar Crown Filaments and the Polar Magnetic Field
Authors: Topka, K.; Moore, R. L.; Labonte, B. J.; Howard, R.
Bibcode: 1980BAAS...12..893T
Altcode:
No abstract at ADS
Title: X-Ray Observations of Stellar Coronae.
Authors: Topka, K. P.
Bibcode: 1980PhDT.........6T
Altcode:
The Einstein X-Ray Observatory (HEAO-2) has been used to search for
X-ray emission from a wide variety of stars in our galaxy. A significant
fraction of the data was obtained via the 8.5 magnitude stellar survey,
which is reported here. This survey searches for X-ray emission from
all stars brighter than visual magnitude 8.5 that serendipitously fell
into the Imaging Proportional Counter field-of-view of the Einstein
Observatory. The survey includes 227 separate fields that contain a
total of 276 stars with V < 8.5. A wide range of spectral types and
luminosity classes are represented. X-Ray emission in excess of 3-sigma
above local background was discovered from 33 stars; 3-sigma upper
limits have been determined for the remaining 243 stars. Comparison of
X-ray source detection statistics with the expected frequency of stars
brighter than V = 8.5 as a function of spectral type and luminosity
class shows that the present visual magnitude limited survey can
define the X-ray luminosity function for dwarf F stars and provides
constraints for the high luminosity tails of the X-ray luminosity
functions for other types of stars constructed from other Einstein
observations. A second survey reported here is called the Gliese
survey. This survey consists of all nearby stars listed in either of
2 catalogues of the nearest stars that accidentally fell into any CFA
(Center for Astrophysics) Einstein observation. A total of 29 nearby
stars are included in the Gliese survey. Ten were detected, including 4
dwarf M stars and 3 dwarf K stars. Late dwarf K and dwarf M stars are
not effectively sampled by the 8.5 survey because most are fainter
than 8.5 magnitude. The results of the 8.5 and Gliese survey have
been integrated with those of four other Einstein surveys. In total,
X-ray emission has been detected from 156 stars, with most of these
representing initial discoveries. A correlation of X-ray luminosity
with spectral type (soft X-ray H-R Diagram) is presented. Most of
the observations can be explained by the presence of hot coronae
around stars of nearly every spectral type. However, the data is at
variance in many respects to existing theoretical coronal models based
on acoustic flux dissipation. The consequences of these observations
in terms of the presence of stellar outer convection zones, surface
magnetic fields, and rotation rates are discussed.
Title: X-ray observations of stellar coronae
Authors: Topka, Kenneth P.
Bibcode: 1980PhDT.......105T
Altcode:
No abstract at ADS
Title: Discovery of an X-ray star association in VI Cygni (Cyg OB2).
Authors: Harnden, F. R., Jr.; Branduardi, G.; Elvis, M.; Gorenstein,
P.; Grindlay, J.; Pye, J. P.; Rosner, R.; Topka, K.; Vaiana, G. S.
Bibcode: 1979ApJ...234L..51H
Altcode:
A group of six X-ray sources located within 0.4 deg of Cygnus X-3 has
been discovered with the Einstein Observatory. These sources have been
positively identified and five of them correspond to stars in the
heavily obscured OB association VI Cygni. The optical counterparts
include four of the most luminous O stars within the field of view
and a B5 supergiant. These sources are found to have typical X-ray
luminosities of 5 x 10 to the 33rd ergs/s, with temperatures of 10 to
the 6.8th K and hydrogen column densities of 10 to the 22nd/sq cm,
and therefore comprise a new class of low-luminosity galactic X-ray
sources associated with early-type stars.
Title: X-ray Observations of the α Cen System from EINSTEIN.
Authors: Golub, L.; Harnden, F. R., Jr.; Rosner, R.; Topka, K.;
Vaiana, G. S.
Bibcode: 1979BAAS...11..775G
Altcode:
No abstract at ADS
Title: X-ray Observations of Very Late-Type Dwarf Stars from the
EINSTEIN Observatory.
Authors: Rosner, R.; Giacconi, R.; Golub, L.; Harnden, F. R., Jr.;
Topka, K.; Vaiana, G. S.
Bibcode: 1979BAAS...11..776R
Altcode:
No abstract at ADS
Title: On Stars and OB Associations Observed from EINSTEIN.
Authors: Harnden, F. R., Jr.; Golub, L.; Rosner, R.; Seward, F.;
Topka, K.; Vaiana, G. S.
Bibcode: 1979BAAS...11..775H
Altcode:
No abstract at ADS
Title: A Magnitude Limited Stellar Survey with EINSTEIN.
Authors: Topka, K.; Golub, L.; Harnden, F. R., Jr.; Gorenstein, P.;
Rosner, R.; Vaiana, G. S.
Bibcode: 1979BAAS...11..781T
Altcode:
No abstract at ADS
Title: The Einstein (HEAO 2) X-ray Observatory.
Authors: Giacconi, R.; Branduardi, G.; Briel, U.; Epstein, A.;
Fabricant, D.; Feigelson, E.; Forman, W.; Gorenstein, P.; Grindlay,
J.; Gursky, H.; Harnden, F. R.; Henry, J. P.; Jones, C.; Kellogg,
E.; Koch, D.; Murray, S.; Schreier, E.; Seward, F.; Tananbaum, H.;
Topka, K.; Van Speybroeck, L.; Holt, S. S.; Becker, R. H.; Boldt,
E. A.; Serlemitsos, P. J.; Clark, G.; Canizares, C.; Markert, T.;
Novick, R.; Helfand, D.; Long, K.
Bibcode: 1979ApJ...230..540G
Altcode:
The Einstein (HEAO 2) X-ray Observatory, launched in 1978, includes
a fully imaging focusing X-ray telescope with an angular resolution
of a few arc sec, a field of view of up to one deg, and a sensitivity
several hundred times greater than previously available in any X-ray
astronomy experiment. A high-resolution imager, an imaging proportional
counter, a focal plane crystal spectrometer, and a monitor proportional
counter are among the principal instruments on board the Einstein
X-ray Observatory. About 20% of the total effective observing time
in the first year of the X-ray astronomy experiment has been reserved
for guest observers.
Title: Soft X-ray structure of the Coma cluster of galaxies.
Authors: Gorenstein, P.; Fabricant, D.; Topka, K.; Harnden, F. R., Jr.
Bibcode: 1979ApJ...230...26G
Altcode:
Results are reported for an observation of the Coma cluster with
an imaging X-ray telescope system aboard a sounding rocket. A
two-dimensional X-ray map of the cluster in the energy range from
0.15 to 2.0 keV is presented. The radial distribution, granularity,
and ellipticity of the X-ray surface brightness are investigated, and
the spectrum and flux within the field of view are analyzed. These
properties are then examined quantitatively by comparing the
observations with models through the use of a chi-squared test. It is
found that: (1) no single galaxy contributes more than a few percent
of the total X-ray flux of the Coma cluster; (2) the X-ray source
is diffuse but granular on a scale of several arcmin, particularly
in the central region; (3) the centroid of the X-ray source is at a
local intensity minimum; and (4) the data are most consistent with an
isothermal hydrostatic model.
Title: Detection of soft X-rays from alpha Lyrae and eta Bootis with
an imaging X-ray telescope.
Authors: Topka, K.; Fabricant, D.; Harnden, F. R., Jr.; Gorenstein,
P.; Rosner, R.
Bibcode: 1979ApJ...229..661T
Altcode:
Results are presented for observations of Alpha Lyr (Vega) and Eta
Boo with an imaging X-ray telescope during two rocket flights. It is
found that Vega and Eta Boo are soft X-ray sources with respective
luminosities of approximately 3 x 10 to the 28th erg/s (0.15-0.8 keV)
and 1 x 10 to the 29th erg/s (0.15-1.5 keV). Surface X-ray luminosities
of about 640,000 erg/sq cm per sec for Vega and 300,000 erg/sq cm
per sec for Eta Boo are estimated and shown to fall within the range
of solar coronal X-ray emission. It is concluded that in view of the
substantially larger surface areas of these stars, the relatively large
total soft X-ray luminosity (as compared with that of the sun) can in
both cases be understood as resulting from a moderately active corona,
although the Vega observation is in severe conflict with simple models
for X-ray emission from single main-sequence stars.
Title: Initial Results from the Einstein Survey of Stellar
Low-Luminosity X-ray Sources
Authors: Vaiana, G.; Forman, W.; Giacconi, R.; Gorenstein, P.; Pye,
J.; Rosner, R.; Seward, F.; Topka, K.
Bibcode: 1979BAAS...11..446V
Altcode:
No abstract at ADS
Title: Spatially resolved measurements of an Fe XVII-XXIV X-ray line
complex in the halo of M87 with an imaging telescope.
Authors: Fabricant, D.; Topka, K.; Harnden, F. R., Jr.; Gorenstein, P.
Bibcode: 1978ApJ...226L.107F
Altcode:
No abstract at ADS
Title: Soft X-ray structure of the Perseus cluster of galaxies.
Authors: Gorenstein, P.; Fabricant, D.; Topka, K.; Harnden, F. R.,
Jr.; Tucker, W. H.
Bibcode: 1978ApJ...224..718G
Altcode:
A 0.5-1.5-keV X-ray image of the Perseus cluster of galaxies was
obtained with a focusing telescope system aboard a sounding rocket. The
source consists of a region of diffuse emission plus a superposed
central source in the vicinity of NGC 1275 smaller than 4 arcmin in
diameter that accounts for one-quarter of the total intensity within a
radius of 25 arcmin. The results for the diffuse source are consistent
with the isothermal-hydrostatic picture in which the hot gas has a
core radius of 17 arcmin and is approximately symmetric about NGC
1275. Several isothermal-hydrostatic models are considered which
relate the size and temperature of the diffuse X-ray source with the
core radius of the galaxies and their velocity dispersion. Fixing the
velocity dispersion at values measured by Chincarini and Rood (1971)
requires the core radius of the galaxies to be 28 + or - 9 arcmin, which
is larger than present measurements. Conversely, fixing the core radius
of the galaxies at 8 arcmin requires a smaller velocity dispersion or
a condition in which the velocity distribution is anisotropic. Upper
limits on the intrinsic X-ray absorption of the central source place
the bulk of its X-ray emission beyond the nuclear region of NGC 1275.
Title: Structure of the X-ray source in the Virgo cluster of galaxies.
Authors: Gorenstein, P.; Fabricant, D.; Topka, K.; Tucker, W.; Harnden,
F. R., Jr.
Bibcode: 1977ApJ...216L..95G
Altcode:
High-angular-resolution observations in the 0.15-1.5-keV band with an
imaging X-ray telescope shows the extended X-ray source in the Virgo
cluster of galaxies to be a diffuse halo of about 15 arcmin core radius
surrounding M87. The angular structure of the surface brightness
is marginally consistent with either of two simple models: (1) an
isothermal (or adiabatic or hydrostatic) sphere plus a point source
at M87 accounting for 12% of the total 0.5-1.5-keV intensity or (2)
a power-law function without a discrete point source. No evidence for
a point source is seen in the 0.15-0.28-keV band, which is consistent
with self-absorption by about 10 to the 21st power per sq cm of matter
having a cosmic abundance. The power-law models are motivated by the
idea that radiation losses regulate the accretion of matter onto M87
and can account for the observed difference in the size of the X-ray
source as seen in the present measurements and at higher energies.
Title: Short Observations of Bright Stars with a Rocket Borne Imaging
X-Ray Telescope.
Authors: Topka, K.; Fabricant, D.; Harnden, F. R., Jr.; Gorenstein, P.
Bibcode: 1977BAAS....9..560T
Altcode:
No abstract at ADS
Title: Soft X-Ray Structure of the Coma Cluster of Galaxies
Authors: Gorenstein, P.; Fabricant, D.; Topka, K.; Harnden, F. R., Jr.
Bibcode: 1977BAAS....9..560G
Altcode:
No abstract at ADS
Title: Comparison of X-Ray Structure of Clusters of Galaxies with
Thermal Models of the Intracluster Gas.
Authors: Fabricant, D.; Topka, K.; Harnden, F. R., Jr.; Gorenstein, P.
Bibcode: 1977BAAS....9..560F
Altcode:
No abstract at ADS
Title: A soft X-ray image of the Algol region.
Authors: Harnden, F. R., Jr.; Fabricant, D.; Topka, K.; Flannery,
B. P.; Tucker, W. H.; Gorenstein, P.
Bibcode: 1977ApJ...214..418H
Altcode:
Algol (Beta Persei) has been detected in two separate exposures of
an imaging X-ray telescope. The 0.15- to 2-keV X-ray luminosity is
approximately 2 by 10 to the 30th power erg/s. The X-ray flux is
interpreted as thermal emission produced by direct accretion of mass
from the K star to the B8 member of the triple star system.
Title: An X-Ray Image of M87 and the Virgo Cluster of Galaxies.
Authors: Gorenstein, P.; Topka, K.; Fabricant, D.; Harnden, F. R., Jr.
Bibcode: 1976BAAS....8..553G
Altcode:
No abstract at ADS
Title: Detection of η Bootes with an Imaging X-Ray Telescope.
Authors: Harnden, F. R., Jr.; Fabricant, D.; Topka, K.; Gorenstein, P.
Bibcode: 1976BAAS....8..529H
Altcode:
No abstract at ADS