HUBBLE SPACE TELESCOPE

   DAILY REPORT #2885

PERIOD COVERED:  0000Z (UTC) 06/01/01 - 0000Z (UTC) 06/04/01

Daily Status Report as of 155/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Four 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 Two Sets of 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.

    1.3 Completed Five 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.

    1.4 Completed Three Sets of 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.

    1.5 Completed Two Sets of WF/PC-2 9132 (Resolving the Puzzling Dark 
Mass Concentration in Abell 1942)

        The WF/PC-2 was used to make observations that will significantly 
improve the precision and localized position of a puzzling 
signal.  Independent lensing analyses of two optical datasets reveal a 
striking mass concentration south of the cluster center with no obvious 
visible source counterpart.  Placed at the redshift of the cluster the 
implied mass would be M{0.5h^-1mboxMpc} >= 1* 10^14M_odot.  The absence of 
an obvious excess of faint sources in suitably deep infrared images makes 
it highly unlikely that such a strong lensing signal can be caused by a 
projected background cluster of galaxies.  No anomalous activity was reported.

    1.6 Completed Sixteen Sets of 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.

    1.7 Completed Two 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.

    1.8 Completed Two Sets of 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.

    1.9 Completed Two Sets of 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.

    1.10 Completed Two Sets of WF/PC-2 8819 (Cycle 9 PSF Characterization)

        The WF/PC-2 was used to provide a subsampled point spread function 
(PSF) over the full WF/PC-2 field to verify PSF stability, support PSF 
fitting photometry, and test PSF subtraction as well as dithering 
techniques {e.g., effects of the OTA breathing and CCD gain}.  There were 
no reported problems.

    1.11 Completed WF/PC-2 9149 (The Nature Of The Most Luminous Star- 
Forming Galaxies In The Redshift Range 0.4 To 1.5)

      The WF/PC-2 was used to perform additional ISO deep surveys that have 
previously uncovered a population of galaxies which are making stars at the 
fantastic rate of > 100 M_odotyr^-1 in the redshift range from 0.4 to 
1.5.  However this population evolves rapidly and luminous star-forming 
galaxies are 5 to 10 times more numerous at z=1 than today.  Combination of 
ISO data with radio {VLA}, sub-mm {SCUBA} and optical data shows that they 
contribute a major fraction {30-50$ representing only a few percent of the 
field galaxy population.  HST imaging of a small subsample of these 
galaxies indicates that most of them are disks showing disrupted 
morphologies or possessing companions, emphasizing the role of merging in 
their star formation history.  The proposal completed without incident.

    1.12 Completed Two Sets of WF/PC-2 8682 (A Snapshot Study of 
0bservational Cosmology)

        The WF/PC-2 was used to examine the observational constraints on 
the cosmic star formation history that is currently among the most active 
fields in observational cosmology.  The most widely used tracer of the 
co-moving volume-averaged star formation rate {SFR} is the UV luminosity 
density, which early results found to peak at z~1- 2.  The apparent 
identification of the primary epoch of metal production and star formation 
in the Universe led to intense theoretical and observational 
interest.  Nevertheless, and remarkably for such a fundamental observation, 
little is known about the history of star formation in the Universe beyond 
its global average.  There were no reported anomalies.

    1.13 Completed WF/PC-2 8720 (Masses and Multiplicity of Nearby Free- 
floating Methane and L Dwarfs)

        The WF/PC-2 was used to observe 50 very-low-mass objects in the 
solar neighborhood with spectral types of L0 and later {including several 
dwarfs with Methane absorption bands in their atmospheres}.  These objects 
will be observed in two filter bands with the aim to identify close 
companions, measure their colors, and to obtain first epoch data of the 
newly discovered binaries.  The observations completed nominally.

    1.14 Completed WF/PC-2 9133 (Imaging of Gravitational Lenses)

        The WF/PC-2 was used to observe gravitational lenses that offer 
unique opportunities to study cosmology, galactic structure, galaxy 
evolution, quasar hosts and extinction.  They are also the only sample of 
galaxies selected on the basis of their mass rather than their luminosity 
or surface brightness.  While gravitational lenses can be discovered with 
ground-based optical and radio observatories, converting them from 
curiosities into scientific tools requires HST.  There were no reported 
anomalies.

    1.15 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.

    1.16 Completed WF/PC-2 9069 (Proper Motions in Extragalactic Optical Jets)

        The WF/PC-2 was used to observe the flow velocity of extragalactic 
jets which is a crucial missing parameter in our understanding of these 
objects.  We would like to build on our successful HST proper motion 
measurements in M87, and propose similar measurements in four other optical 
jets.  The proposal completed with no reported problems.

    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 9104 (A Study of Proplyds and a Protostellar 
Condensation at the Center of M20)

        The WF/PC-2 was used to observe the Trifid nebula {M20} that is a 
well-known prominent optical HII region trisected by bands of obscuring 
dust lanes and excited by an O7.5 star HD 164492A.  Our
recent study of near-IR ground-based observations of this region at J, H, K 
and L show all seven components of HD 164492 {A to G} identified 
optically.  Our sub-arcsecond radio continuum VLA and ground- based 
observations of M20 also show free-free emission from three stellar sources 
{B, C and D} and a bright rim outlining a protostellar condensation {TC1} 
lying close to the O7V star {HD 164492A} at the center of the 
nebula.  Based on a number of strong arguments, these stars have disks 
associated with them and their envelopes are photoionized externally by the 
UV radiation from the hot central star, HD 164492A.  These proposed WFPC2 
observations are intended to search for neutral protoplanetary disks 
``proplyds'', to study the optically bright rim of ionized gas associated 
with TC1 for signs of star formation, and to make a detailed subarcsecond 
determination of extinction toward the dust lanes of M20 using HAlpha and 
6cm data.  There were no reported problems.

    1.19 Completed WF/PC-2 8654 (Confirmation of Black Hole, Planetary, and 
Binary Microlensing Events)

        The WF/PC-2 was used to take images of five MACHO Project 
microlensing events in order to confirm our microlensing models which 
indicate that these events were caused by black holes and stars with 
extra-solar planets.  The proposal completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 20
Successful: 20

  Scheduled Re-acquisitions: 21
Successful: 21

    2.2 FHST Updates:
Scheduled: 61
Successful: 61

    2.3 Operations Notes:

        The STIS instrument remains in safe.

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

        The 486 engineering status buffer (ESB) was dumped and cleared at 
152/1755Z.  Using the same ROP, the ESB limits were adjusted at 153/1950Z.

        A TTR and HSTAR 8240 were written when a GCMR was not acknowledged 
by the NCC at 152/194800Z.  The following GCMR was successful.

        TTRs were written for required re-transmits during NSSC-1 load 
uplinks at 153/042858Z and at 154/124316Z.  In each case, ROP NS-5 was used 
to clear SI C&DH errors.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW