HUBBLE SPACE TELESCOPE

   DAILY REPORT #2881

PERIOD COVERED:  0000Z (UTC) 05/25/01 - 0000Z (UTC) 05/29/01

Daily Status Report as of 149/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Eight Sets of WF/PC-2 8828 (Cycle 9 Supplemental Darks pt3/3)

        The WF/PC-2 was used to obtain three dark frames every day to 
provide data for monitoring and characterizing the evolution of hot 
pixels.  The proposal completed with no reported problems.

    1.2 Completed WF/PC-2 8585 (Cosmological Parameters from Type Ia 
Supernovae at High Redshift)

        The WF/PC-2 was used to measure the cosmological parameters, Omega, 
Lambda, and thus the curvature, Omega_k, using Type Ia supernovae {SNe Ia} 
as calibrated standard candles.  There were no reported problems.

    1.3 Completed WF/PC-2 9073 (Ultraluminous X-Ray Sources and 
Intermediate Mass Black Holes)

        The WF/PC-2 was used to observe ultraluminous X-ray sources {ULX} 
that are second only to AGNs in point-source luminosity yet they have no 
known optical counterparts.  These extraordinary X-ray objects, which 
radiate at the Eddington luminosity of a 30-100 solar mass object, are 
non-nuclear sources in normal disk galaxies.  One explanation is that they 
are binary systems where the accreting black hole has a mass of 30-100 
solar masses, although this challenges stellar evolutionary models, which 
do not predict remnants larger than about 10 solar masses.  Another 
possibility is that ULXs are intermediate mass black holes acting as 
micro-quasars in galaxy disks and representing the link between stellar 
black holes {4-10 solar masses} and supermassive black holes {10^6-10^10 
solar masses}.  The observations completed with no reported problems.

    1.4 Completed Four Sets of WF/PC-2 9045 (The Relationship Between Radio 
Luminosity and Radio-Loud AGN Host Galaxy Properties)

        The Wf/PC-2 was used to determine the relationship between the 
properties of the host galaxies of radio-loud AGN and their radio 
luminosities.  Previous studies in this area with the HST have concentrated 
on the 3C sample which shows a tight correlation between luminosity and 
redshift, such that evolutionary effects cannot be distinguished from those 
depending upon radio luminosity.  Our sample of 46 radio galaxies at z ~ 
0.5 comes from four complete, low-frequency-selected samples of radio 
sources with differing flux limits.  Thus the total sample spans an 
unprecedented three orders of magnitude in radio luminosity at a fixed 
redshift interval.  The proposal completed with no reported problems.

    1.5 Completed WF/PC-2 8677 (Extragalactic Novae: the Maximum Magnitude 
- Rate of Decline Relation in NGC 4472)

        The WF/PC-2 was used to accomplish two goals: {1} to provide the 
first homogeneous observational constraints on theoretical models for novae 
outbursts; and {2} to assess the reliability of novae as standard candles 
by using WFPC2 to collect well sampled light curves for 20-50 novae in the 
supergiant elliptical galaxy NGC 4472, the brightest galaxy within 30 
Mpc.  Both the length of the observing window and the temporal sampling of 
the observations are specifically designed to ensure that the novae peak 
magnitudes and decline rates are measured accurately.  These data will be 
used to construct the first `Maximum Magnitude versus Rate of Decline' 
{MMRD} relation for a galaxy beyond the Local Group.  This relation is not 
only a potentially powerful standard candle, but its shape and dispersion 
are directly linked to physical parameters which govern the physics of 
novae outbursts such as the white dwarf mass, temperature and mass 
accretion rate.  The proposal completed with no reported problems.

    1.6 Completed WF/PC-2 8707 (A Study of Star Formation in Galactic 
Resonance Rings)

        The WF/PC-2 was used to observe rings of star formation which are a 
common phenomenon of early-type spiral galaxies.  Most rings form by gas 
cloud collisions near resonances, under the continuous action of gravity 
torques from a bar perturbation, while a small number form in response to a 
mild tidal interaction with a nearby companion.  In either case, a 
resonance is a very special place in any galaxy where star formation can be 
enhanced and may proceed either as a starburst or continuously over a long 
time period. Resonance rings are natural dynamical laboratories for star 
cluster formation and evolution.  The observation completed normally with 
no reported problems.

    1.7 Completed WF/PC-2 8583 (Imaging Snapshots of Asteroids)

        The WF/PC-2 was used to obtain images of the fifty largest main 
belt asteroids that have favorable apparitions during cycle 9.  The images 
will be searched for companion bodies, as well as mineralogical variegation 
on the resolved main bodies.  There were no reported problems.

    1.8 Completed Eight Sets of WF/PC-2 8699 (The Origin of Short-Period 
Comets)

        The WF/PC-2 was used to detect and characterize cometary nuclei in 
order to determine the basic physical properties of a large fraction of the 
population of short-period comets.  By acquiring statistically significant 
data, we can study the origin of this family of comets and test the 
hypothesis that they are collisional fragments from the Kuiper Belt 
Objects.  The observations completed with no reported problems.

    1.9 Completed WF/PC-2 9106 (The Biggest Black Holes)

        The WF/PC-2 was used to perform searches for supermassive black 
holes in galaxy centers that have led to the discoveries that {1} most or 
all hot galaxies contain massive dark objects at their centers, presumably 
black holes; and {2} there is a tight correlation between the black-hole 
mass and the luminosity-weighted velocity dispersion of the hot component 
of the galaxy.  This remarkable relationship suggests a strong link between 
black-hole formation, AGN activity, and galaxy formation, and once it is 
understood this link should advance our understanding of all three 
processes.  There were no reported problems.

    1.10 Completed Two Sets of WF/PC-2 8602 (A Snapshot Survey of the Sites 
of Recent, Nearby Supernovae)

        The WF/PC-2 was used to conduct a snapshot survey in V and I of the 
sites of the nearby SNe, which have precisely known positions, to obtain 
high-resolution information on their local environment.  The proposal 
completed with no reported problems.

    1.11 Completed WF/PC-2 8604 (Stellar Populations Across the Small 
Magellanic Cloud (SMC) : History and Structure)

        The WF/PC-2 was used to investigate the structure and evolutionary 
history of the SMC by obtaining a series of 50 three-color snapshots of 
selected SMC regions.  With this polling of SMC field star properties, we 
will produce color-magnitude diagrams in the U, V and I bands which will 
reach V~23.5 in regions too crowded to be observed accurately from the 
ground.  The observations completed nominally.

    1.12 Completed Three Sets of WF/PC-2 8579 (A Search for the Martian 
Dust Belts)

        The WF/PC-2 was used to Mars that has been long believed should be 
encircled by two faint rings of dust, one originating from each of its 
moons Phobos and Deimos.  Similar dust rings have recently been associated 
with all the inner small moons of Jupiter.  Earth will pass through Mars' 
equatorial plane within weeks of its opposition, providing a unique 
opportunity to detect these rings via direct imaging.  The proposal 
completed nominally.

    1.13 Completed WF/PC-2 9163 (Kinematics Of Emission-Line Gas Disks In 
Radio-Quiet Galaxies)

        The WF/PC-2 was used to measure central black hole {BH} masses from 
the rotation rate of the emission-line gas, and to determine the nature and 
structure of the gas disks. Three galaxies with no radio jets and with 
Halpha+[NII] emission have been identified, which have dust disks similar 
to those commonly seen in our sample of radio-loud active galaxies.  All 
observations completed nominally.

    1.14 Completed WF/PC-2 9092 (V605 Aql: Sakurai's Older Brother)

        The WF/PC-2 was used to observe post-AGB stars that can undergo a 
final episode of helium shell burning after the star has ejected a 
planetary nebula and has started on the white dwarf track.  Starting in 
1996 Sakurai's star has been observed to undergo a final helium shell 
flash.  The same series of events occurred in V605 Aql 91 years ago.  These 
stars both ejected a shell of gas first seen as a pseudo-photosphere and 
then as a thick dust envelope.  The shells are expanding at about 100 km 
s-1 and in the case of V605 Aql the shell now appears about 1" 
across.  This proposal will image this shell.  The proposal completed with 
no anomalous activity.

    1.15 Completed WF/PC-2 8718 (Understanding the Anomalous Hot Stellar 
Population in Galactic Globular Clusters)

        The WF/PC-2 was used to image in mid- {F255W} and near-UV {F336W} 
the globular cluster NGC5986.  During the HST survey, it was found that 
this object has a horizontal branch with an anomalously extended blue 
tailand puzzling gaps along it.  There were no reported problems.

    1.16 Completed WF/PC-2 9103 (Resolving New Examples of Edge-on Young 
Stellar Object Disks)

        The WF/PC-2 was used to perform edge-on, optically thick 
circumstellar disks observations have been previously imaged by the Hubble 
Space Telescope in association with several nearby young stars.  In these 
systems, the central star is occulted from direct view, large PSF artifacts 
are absent, and the disk reflected light is clearly seen.  It is for these 
objects in nearby star-forming regions that HST has provided the best, 
highest resolution {7-10 AU} views to date of disks which may form 
planetary systems like our own.  Comparison of edge-on disk images with 
scattered light models has allowed key structural parameters such as the 
disk outer radius, vertical scale height, radial density profile, total 
mass, and dust grain properties to be determined.  No problems were reported.

    1.17 Completed WF/PC-2 8591 (The Smallest Nuclear Black Holes)

        The WF/PC-2 was used to observe small nuclear black holes which are 
the last major unexplored part of BH parameter space, searching for the 
smallest BHs that HST can possibly find.  The proposal completed with no 
reported anomalies.

    1.18 Completed WF/PC-2 9107 (The Fundamental Plane for Nuclear Black Holes)

        The WF/PC-2 was used to conduct more in-depth searches for 
supermassive black holes in galaxy centers.  Previous work has led to the 
discoveries that {1} most or all hot galaxies contain massive dark objects 
at their centers, presumably black holes; {2} there is a remarkably tight 
correlation between the black-hole mass and the luminosity-weighted 
velocity dispersion of the hot component of the galaxy. T his mbh-Sigma 
relation has a scatter which is <0.3 dex in mbh and consistent with 
zero.  This relationship suggests a strong link between black-hole 
formation, AGN activity, and galaxy formation, and once it is understood 
this link should advance our understanding of all three processes.  The 
goal of this proposal is to investigate the scatter in the mbh-Sigma 
relation and the role of possible second parameters, by examining a sample 
of galaxies at fixed velocity dispersion Sigma=200+/- 20 kms.  This 
approach decouples the effects of a second parameter from uncertainties in 
the shape of the mbh-Sigma relation, and minimizes spurious correlations 
because all of the galaxies will be studied using the same well-tested 
observational and modeling techniques.  No anomalous activity occurred.

    1.19 Completed WF/PC-2 8634 (Atmospheric Variability on Uranus and Neptune)

        The WF/PC-2 was used to obtain snapshot observations of Uranus and 
Neptune to monitor changes in their atmospheres on time scales of months to 
years.  Uranus is rapidly approaching equinox in 2007, with another 4 
degrees of latitude in the northern hemisphere becoming visible every 
year.  Recent HST images during this unique epoch have revealed: {i} 
strongly wavelength-dependent latitudinal structure, {ii} the presence of 
numerous visible-wavelength cloud features in the northern hemisphere, and, 
{iii} in the near-IR, discrete features northward of 25degrees N that have 
the highest contrast ever seen for a Uranian cloud.  Long-term ground- 
based observations show seasonal brightness changes whose origins are not 
well understood.  Recent IR images of Neptune obtained using adaptive 
optics on the Keck Telescope indicate that a new "Bright Companion" type of 
feature has recently appeared in the southern hemisphere.  Snapshot 
observations of these two dynamic planets can supply context in which to 
discern the nature of long-term changes in their latitudinal atmospheric 
bands and to track the appearance, movement, and disappearance of discrete 
albedo features.  There were no reported problems.

    1.20 Completed Seven Sets of WF/PC-2 8601 (A Snapshot Survey of 
Probable Nearby Galaxies)

        The WF/PC-2 was used to continue the very successful snapshot 
survey in order to use the high spatial resolution of HST to determine 
whether selected galaxies are nearby on the basis of resolution into stars, 
and the magnitudes and colors of the brightest stars.  There were no 
reported problems.

    1.21 Completed Six Sets of WF/PC-2 8811 (Cycle 9 Standard Darks)

        The WF/PC-2 was used to obtain dark frames every week in order to 
provide data for the ongoing calibration of the CCD dark current rate, and 
to monitor and characterize the evolution of hot pixels.  Over an extended 
period these data will also provide a monitor of radiation damage to the 
CCDs.  The proposal completed with no reported problems.

    1.22 Completed Three Sets of WF/PC-2 8599 (A Census of Nuclear Star 
Clusters in Late-Type Spiral Galaxies)

        The WF/PC-2 was used to conduct an I-band snapshot survey of a 
well-defined sample of nearby, face-on spiral galaxies of type Scd or 
later.  The proposal completed nominally.

    1.23 Completed WF/PC-2 8829 (Observatory Focus Monitor)

        The WF/PC-2 was used to analyze the HST focus which drifts slowly 
and shows evidence of undergoing slips of a few microns at random 
times.  The rate of the WFPC2 monitoring program is insufficient to track 
and/or understand OTA behavior in order to request timely and appropriate 
secondary mirror corrections.  This 14-orbit program obtains a large amount 
of high signal to noise focus data, sometimes in two Science Instruments at 
once, and will be sufficient to more accurately define the HST 
focus.  There were no reported problems.

    1.24 Completed WF/PC-2 8816 (Cycle 9 UV Earthflats)

        The WF/PC-2 was used to obtain sequences of Earth streak flats to 
improve the quality of pipeline flat fields for the WFPC2 UV filter set and 
in order to monitor flat field stability.  There were no reported problems.

    1.25 Completed WF/PC-2 8812 (Cycle 9 Internal Monitor)

        The WF/PC-2 was used to obtain routine internal monitors for WFPC2 
in order to monitor the health of the cameras.  A variety of internal 
exposures are obtained in order to provide a monitor of the integrity of 
the CCD camera electronics in both bays {gain 7 and gain 15}, a test for 
quantum efficiency in the CCDs, and a monitor for possible buildup of 
contaminants on the CCD windows.  There were no reported problems.

    1.26 Completed WF/PC-2 8592 (Pixel Microlensing of M87)

        The WF/PC-2 was used to undertake a pixel microlensing study of M87 
in order to: 1} probe the lower end of the M87 IMF via star-star lensing, 
2} possibly obtain the first evidence of Massive Compact Objects (MACHOs) 
in the halo of a galaxy other than our own, and 3} search for intracluster 
MACHOs.  The proposal completed nominally.

    1.27 Completed WF/PC-2 9138 (Host Galaxies of Gravitationally Lensed 
Quasars)

        The WF/PC-2 was used to perform imaging studies of quasar host 
galaxies at high redshift that are biased toward detecting luminous 
hosts.  Gravitational lensing combined with optical and near-IR imaging 
enhances their detectivity and has nearly doubled the number of known hosts 
at z>1.  Lens studies have successfully imaged hosts with lower 
luminosities at farther distances beneath a larger fraction of quasars than 
imaging of non- lensed quasars.  We propose deep WFPC2 follow-up imaging of 
five lensed systems in the F555W and F814W filters, which offer unique 
opportunities for detailed studies of faint, high-redshift, quasar 
hosts.  The proposal completed as planned.

    1.28 Completed WF/PC-2 8600 (Dwarf Elliptical Galaxy Snapshot Survey III)

        The WF/PC-2 was used to extend our V and I snapshot survey of 
nearby dwarf elliptical {dE} galaxies to include a sample of 30 bright dE 
with significant globular cluster {GC} populations.  There were no reported 
problems.

    1.29 Completed WF/PC-2 8597 (The Fueling of Active Nuclei: Why are 
Active Galaxies Active?)

        The WF/PC-2 was used to investigate the accretion onto massive 
black holes that are believed to be the energy source for AGN.  However, 
evidence for black holes in quiescent galaxies has also been reported.  Why 
are these galaxies inactive?  One possibility is that active galaxies are 
better at providing fuel to the nuclear region than quiescent 
galaxies.  Other possible fueling mechanisms such as ``bars-within-bars'' 
or nuclear spirals cannot be investigated from the ground because they are 
relatively small features in the ISM.  The observations were completed as 
planned.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 50
Successful: 50

  Scheduled Re-acquisitions: 16
Successful: 16

    2.2 FHST Updates:
Scheduled: 88
Successful: 87

        Per HSTAR 8234, the roll delay update scheduled for 146/113800Z 
failed due to tracker #3.  The subsequent acquisition was successful.

    2.3 Operations Notes:

        The STIS instrument remains in safe.

        Using ROP SR-01A, the SSR EDAC error counter was cleared eight times.

        On two occasions, the CCS engineering status buffer limits were 
adjusted per ROP DF-18A.

        As directed by an operations request, the EPS limits were modified 
due to the high Sun time for the period day 143 to day 158.  This was 
accomplished at 146/0057Z.

        Per HSTAR 8233, the parameter EFG1_3T flagged out-of-limits low 
with a value of 17.9479 degC.  The limit is 18.00 degC.

        A TTR was written for a required re-transmit at 147/1245Z during a 
NSSC-1 load.  Later, using ROP NS-5, NSSC-1 errors were reset.

        At 148/083945Z, operations personnel noted that QF1STOPF and 
QF1SSLEX had flagged out-of-limits while HST was guiding on FGS-3 
only.  This was indicates a possible FGS-1 "bit flip" during a ZOE.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW