HUBBLE SPACE TELESCOPE

  DAILY REPORT #2900

PERIOD COVERED:  0000Z (UTC) 06/22/01 - 0000Z (UTC) 06/25/01

Daily Status Report as of 176/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Six 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 8177 (Investigating Type Ia Supernovae and an 
Accelerating Universe)

        The WF/PC-2 was used to obtain rest frame U and B photometry for 
four z~ 0.85 Supernova (SN) Ia.  These observations will be coupled to 
ground-based rest frame V photometry and spectra.  These data, combined 
with previous samples, will extend the D_L vs. z diagram for SN Ia to 
z~0.85, and allow us to discriminate the redshift dependence of supernova 
magnitudes in an accelerating Universe from that expected to result from 
systematic effects such as age of the stellar population, chemical 
evolution, a drift in the properties of dust, and weak gravitational 
lensing.  The proposal completed with no reported problems.

    1.3 Completed WF/PC-2 9085 (Measuring The Masses Of High-Z Quasar Host 
Galaxies)

        The WF/PC-2 was used to investigate the close link between 
black-hole mass and spheroid mass in both quiescent and active galaxies in 
the local universe.  Consequently black-hole and spheroid formation/growth 
are now viewed as intimately related processes, and establishing the mass 
of quasar host galaxies as a function of redshift is now seen as a key 
measurement in observational cosmology.  From the Cycle 7 NICMOS program, 
the best estimate to date of the mass evolution of the hosts of both 
radio-quiet and radio-loud quasars out to z ~eq 2 has been derived.  Under 
the assumption of passive stellar-population evolution our results are 
consistent with the black-hole/spheroid population being unchanged out to z 
~eq 2.  However, the crucial assumption of passive evolution needs to be 
tested.  All observations competed nominally.

    1.4 Completed Two Sets of WF/PC-2 8820 (Wavelength Stability of Narrow 
Band and Linear Ramp Filters)

        The WF/PC-2 was used to verify the mapping of wavelength as a 
function of CCD position on linear ramp filters and to check for changes in 
central wavelengths of the narrow band filters.  The proposal completed 
nominally.

    1.5 Completed Three Sets of 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.

    1.6 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.

    1.7 Completed Two 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.

    1.8 Completed WF/PC-2 9122 (The Physics of X-Ray/Optical Jets)

        The WF/PC-2 was used to perform an important new probe of the 
physics of large-scale radio jets that is possible with the discovery of 
resolved X-ray/optical jets.  The optical emission comes from high energy 
electrons, which have short radiative lifetimes and so pinpoint particle 
acceleration sites.  Spectral energy distributions of knots in two jets 
suggest the X-rays come from lower energy electrons inverse-Compton 
scattering the {beamed} cosmic microwave background.  This requires the jet 
to be still relativistic on kiloparsec scales {out to ~1 Mpc for the 
high-redshift jets.}.  This model robustly constrains both the bulk 
relativistic speed and the minimum electron energy in the jet, which 
together determine the total jet power.  To probe jet energetics and 
physics generally, and to test the ``Compton/CMB'' interpretation 
specifically, it is proposed to execute deep HST imaging of three 
X-ray/optical jets {PKS 1127--145, PKS 0637--752, 3C 371} and one optical 
jet {PKS 2201+044}, plus Chandra observations of the latter two.  The 
proposal completed with no reported problems.

    1.9 Completed Two Sets of WF/PC-2 8632 (A UV Atlas of Nearby Galaxies)

        The WF/PC-2 was used to perform a snapshot survey of local galaxies 
at UV wavelengths with the F300W filter.  The aim of the project is to 
build a reference UV Atlas of normal galaxies, whose optical images are 
well known, with the highest possible degree of information, covering all 
the morphological types and luminosity classes.  The proposal completed 
normally.

    1.10 Completed Three Sets of WF/PC-2 9086 (Investigating the Formation 
History of Spiral Galaxy Halos)

        The WF/PC-2 was used to make observations in order to constrain the 
origin of spiral galaxy halos by studying stellar populations near the tip 
of the red giant branch.  This will be the first systematic study of this 
population in external galaxies and will quadruple the sample of normal 
spiral galaxies for which the halo metallicity distribution function is 
measured.  This larger sample will permit study of the relationship between 
the bulge, disk, and halo components and between halos and globular 
systems.  Such correlations will in turn provide indications as to whether 
the halo, bulge, and globular cluster systems built up nearly 
simultaneously in the early universe or were accreted over time through 
different kinds of merging events.  The proposal completed nominally.

    1.11 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. This 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.

    1.12 Completed WF/PC-2 9267 (Supernova Search)

        The WF/PC-2 was used to search for high-redshift supernovae in 
GO-observed fields, taking advantage of good first-epoch observations and 
of the scheduling opportunities available because STIS is not currently 
observing.  No anomalous activity was reported.

    1.13 Completed WF/PC-2 8773 (Expansion Parallax Distances to Planetary 
Nebulae)

        The WF/PC-2 was used to observe planetary nebulae {PNe} for which 
the lack of reliable distances is especially troubling.  Acquired by 
generalized statistical methods in all but a handful of cases, individual 
PNe distances are often uncertain by factors of two or more.  The 
observations completed nominally.

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

        The WF/PC-2 was to be used investigate the structure and 
evolutionary history of the SMC by obtaining a series of 50 three-color 
snapshots of selected SMC regions.  As detailed in HSTAR 8248 and 2.1, the 
acquisition for this proposal failed and three observations were lost.
2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 19
Successful: 18

Per HSTAR 8247, the acquisition at 175/2247Z failed when the search radius 
limit was exceeded.  The proposal detailed in 1.14 was affected.
  Scheduled Re-acquisitions: 26
Successful: 26

    2.2 FHST Updates:
Scheduled: 41
Successful: 41

    2.3 Operations Notes:

        The STIS instrument remains in safe mode.

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

        In conjunction with the acquisition failure described above, the 
engineering status buffer limits were adjusted at 175/2249Z.  ROP DF-18A 
was used.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW