HUBBLE SPACE TELESCOPE

   DAILY REPORT #2831

PERIOD COVERED:  0000Z (UTC) 03/16/01 - 0000Z (UTC) 03/19/01

Daily Status Report as of 078/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Twelve Sets of STIS/CCD 8562 (Probing the Large Scale 
Structure: Cosmic Shear Observations)

        The Space Telescope Imaging Spectrograph (CCD) was used to probe 
the distortion of light bundles from distant galaxies, looking at the 
statistical properties of the intervening inhomogeneous {dark} matter 
distribution.  The proposal completed nominally.

    1.2 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.

    1.3 Completed Two Sets of WF/PC-2 8698 (Identification of the Galaxy's 
Missing Mass)

        The WF/PC-2 was used to observe the nature of dark matter that is 
one of the key astrophysical questions of the day.  The existence of dark 
matter and its dynamical dominance in the outer parts of our Galaxy and 
spiral galaxies with flat rotation curves is well established.  The MACHO 
project has identified ~half of the Milky Way's dark matter with stellar 
objects of ~0.5 M_sun, probably white dwarfs.  But the location of the 
microlensing in the halo is disputed.  Several have detected two candidate 
halo white dwarfs of L/L_sun ~ 10^-5 in the Hubble Deep Field with 25 +/- 5 
mas/year proper motions.  The observations completed with no reported problems.

    1.4 Completed Seven Sets of WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)

        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 nominally.

    1.5 Completed Six Sets of STIS/CCD 8864 (CCD Dark Monitor-Part 2)

         The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the darks for the CCD.  The proposal completed nominally.

    1.6 Completed Three Sets of STIS/CCD/MA1 8625 (The Metallicity of Gas 
in the Local Universe: Beyond the Milky Way)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
obtain spectra of three QSO/AGN which lie behind nearby galaxies in order 
to measure the metallicity of the interstellar gas at the present epoch 
beyond the local group.  The proposal completed with no reported anomalies.

    1.7 Completed Five Sets of WF/PC-2 8805 (POMS Test Proposal: WFII 
Parallel Archive Proposal Continuation)

        The WF/PC-2 was used to perform a generic target version of the 
WFPC2 Archival Pure Parallel program.  The program will be used to take 
parallel images of random areas of the sky, following the recommendations 
of the Parallels Working Group.  The proposal completed with no reported 
problems.

    1.8 Completed WF/PC-2 8883 (POMS Test Proposal: WFII Backup Parallel 
Archive Proposal II)

        The WF/PC-2 was used to complete a POMS test proposal designed to 
simulate scientific plans.  There were no reported problems.

    1.9 Completed Three Sets of WF/PC-2 8817 (Cycle 9 INTFLAT Sweeps and 
Linearity Test)

        The WF/PC-2 was used to obtain INTFLAT observations in order to 
monitor the pixel to pixel flatfield response and provide a linearity 
check.  The INTFLAT sequences, to be done once during the year, are similar 
to those from the Cycle 8 program 8448.  The images will provide a backup 
database in the event of complete failure of the VISFLAT lamp as well as 
allow monitoring of the gain ratios.  The sweep is a complete set of 
internal flats, cycling through both shutter blades and both gains.  The 
linearity test consists of a series of INTFLATs in F555W, in each gain and 
each shutter.  There was no anomalous activity.

    1.10 Completed Two Sets of STIS/CCD 8591 (The Smallest Nuclear Black Holes)

        The Space Telescope Imaging Spectrograph (CCD) 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.

    1.11 Completed WF/PC-2 8686 (LINERs in Early-type Galaxies: Ionized by 
the UV-upturn Population?)

        The WF/PC-2 was used to investigate the presence of extended 
ionized gas with LINER spectra in a large fraction {60-70%} of early-type 
galaxies.  The observations completed with no reported anomalies.

    1.12 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.

    1.13 Completed Two Sets of STIS/CCD 8865 (Bias Monitor-Part 2)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at 
gain = 4, to build up high-S/N superbiases and track the evolution of hot 
columns.  The proposal completed with no anomalous activity.

    1.14 Completed Three Sets of WF/PC-2 8815 (Cycle 9 Earth Flats)

        The WF/PC-2 was used to monitor flatfield stability.  This proposal 
obtains sequences of Earth streak flats to construct high quality flat 
fields for the WF/PC-2 filter set.  These flat fields will allow mapping of 
the OTA illumination pattern and will be used in conjunction with previous 
internal and external flats to generate new pipeline superflats.  The 
proposal completed nominally.

    1.15 Completed STIS/CCD 8808 (POMS Test Proposal: STIS Non-Scripted 
Parallel Proposal Continuation III)

        The Space Telescope Imaging Spectrograph (CCD) was used to make 
non-scripted, parallel observations as part of a POMS test proposal.  The 
observations completed with no anomalous activity.

    1.16 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.

    1.17 Completed STIS/MA1 8582 (UV Detectability of Bright Quasars in the 
Sloan Fields)

        The Space Telescope Imaging Spectrograph (CCD) was used to examine 
the He II Ly alpha absorption at 304{1+z} Angstrom which is a far more 
sensitive tracer of the intergalactic medium {IGM} than its H I 
counterpart.  The recent detections of such absorption in four quasars, 
albeit with limited data quality and a small sample size, demonstrate the 
great potential of such a probe.  There were no reported problems.

    1.18 Completed STIS/CCD/MA1 8107 (What is the Nature of the Cold Medium 
in Cooling Flow Clusters?)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
observe X-ray spectra of cooling flow clusters of galaxies in an attempt to 
discover the presence of large columns of "cold'' absorbing material.  The 
proposal completed with no reported problems.

    1.19 Completed STIS/MA1 8843 (Cycle 9 MAMA Dark Measurements)

        The Space Telescope Imaging Spectrograph (MA1) was used to perform 
the routine monitoring of the MAMA detector dark noise.  The proposal 
completed nominally.

    1.20 Completed Two Sets of WF/PC-2 8867 (Gamma-Ray Bursts: Discovering 
The Progenitors And Understanding The Explosion - Visits A0-R0)

        The WF/PC-2 was used to observe a gamma-ray burster, 
GRB000926.  Gamma-ray burst astronomy, one of the most active and exciting 
frontiers in astrophysics, is now entering a critical stage -- with 
dramatic leaps in understanding of these events, as well as new 
discoveries.  Improvements in triggering and positioning accuracy provided 
by the SAX and HETE-2 gamma-ray satellites will allow entirely new classes 
of events to be studied.  Given the recent progress in this field, the 
proposers are now in a position to design precision, broadband measurements 
that can provide quantitative information on the as-yet unknown energy 
sources, the explosion geometry, and the surrounding medium.  In 
particular, the growing evidence of an intimate connection between SNe and 
GRBs can be definitively tested.  The proposal completed with no reported 
problems.

    1.21 Completed WF/PC-2 8719 (A Continuation Of A Snapshot Survey Of X- 
Ray Selected Central Cluster Galaxies0

        The WF/PC-2 was used to perform snapshot images of a representative 
subset of the central cluster galaxies from an X-ray selected cluster 
sample that would provide important constraints on the formation and 
evolution of dust in cluster cores that cannot be obtained from 
ground-based observations.  The observations completed as planned.

    1.22 Completed STIS/MA2 8590 (UV Imaging and Spectroscopy of Luminous 
Blue Compact Galaxies from z=0 to z=1)

        The Space Telescope Imaging Spectrograph (MA2) was used to observe 
two well-defined samples of low-mass starburst galaxies, one in the local 
universe {z<0.1} and another at intermediate redshifts {0.2 < z < 
0.7}.  Both samples show optical sizes, morphologies, emission line widths, 
and luminosities comparable to those of LBGs at z=3, and are therefore 
probably the best local analogs and testbeds for further study of 
LBGs.  Our main goals are to: {1} explore the morphologies, surface 
brightness distributions, and half-light radii of nearby starforming 
galaxies in the FUV, near Ly-alpha; {2} search for systematic differences 
among UV, optical, and near-IR morphologies and structural parameters; {3} 
investigate the intrinsic emission and absorption spectra near Ly-alpha of 
starbursting dwarf galaxies, with special attention to Ly- alpha profiles 
and interstellar and stellar photospheric absorption from Si II, O I, C II, 
Si IV, and C IV; {4} measure their FUV-optical colors and dust extinction 
properties; and {5} test the hypothesis that low-mass starbursts are the 
local counterparts of LBGs.  The observation completed normally.

    1.23 Completed WF/PC-2 8581 (A Search For Low-Mass Companions To 
Ultracool Dwarfs)

        The WF/PC-2 was used to search for very low-mass {VLM} companions 
to a complete sample of 120 late-M and L dwarfs, drawn mainly from the 
2MASS and SDSS surveys.  The primary goal is to determine the multiplicity 
of M < 0.1 M_odot dwarfs.  In particular, we aim to identify binary systems 
suitable for long-term astrometric monitoring and mass measurement, and 
systems with cool, sub-1000K companions.  The proposal completed with no 
reported problems.

    1.24 Completed Two Sets of STIS/CCD 8840 (Read Noise Monitor)

        The Space Telescope Imaging Spectrograph (CCD) was used to measure 
the read noise of all the amplifiers on the STIS CCD using pairs of bias 
frames.  Full frame and binned observations are made in both Gain 1 and 
Gain 4, with binning factors of 1 x 1, 1 x 2, 2 x 1 and 2 x 2.  All 
exposures are internals.  The observations completed with no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 23
Successful: 23

  Scheduled Re-acquisitions: 14
Successful: 14

    2.2 FHST Updates:
Scheduled: 40
Successful: 40

    2.3 Operations Notes:

        Due to the instability of the HST Network and to aid with ongoing 
troubleshooting, the Flight Operations Team (FOT) transferred operations 
from the SIMOR to the Building 23 control room  at 075/1800Z.  This move 
allowed the FOT to rapidly switch to an isolated network mode in the event 
of an HST network outage.  Isolation did begin at 076/1622Z and continued 
until 077/0240Z.  The FOT then transferred to the Mission Operations Room 
in Building 3 at 077/1430Z.

        Using ROP SR-1A, the SSR EDAC error counter was cleared ten times.

        Two TTRs were written for required re-transmits during command load 
uplinks.

        SI C&DH errors were reset at 076/1356Z per ROP NS-05.

        The SSR was configured for autonomous engineering record at 
078/0622Z and at 078/0847Z as directed by ROF-SR-8A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW