Hubble Space Telescope Daily Report #2892 – 13 June 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2892

PERIOD COVERED: 0000Z (UTC) 06/12/01 – 0000Z (UTC) 06/13/01

Daily Status Report as of 164/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 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.

1.2 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.

1.3 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.

1.4 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.

1.5 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.

1.6 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.

1.7 Completed WF/PC-2 9115 (The Evolution of Extreme Gas Rich Galaxies)

The WF/PC-2 was used to observe a recently discovered sample of the
closest known low surface brightness, very gas-rich dwarf galaxies outside
of the Local Group. These galaxies represent an extreme star formation
environment, where the fuel for star formation appears plentiful, the local
environment {the Centaurus A group of galaxies} provides opportunities for
tidally-induced star formation, and yet star formation appears to be
surpressed {by two orders of magnitude} compared to other `typical’
galaxies. The goal is to understand the star formation history in this
puzzling environment of low stellar density and high gas content. By
resolving the underlying stellar component, the observer will obtain
critical information on the mean metallicity and star formation history of
these galaxies.

1.8 Completed 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.

1.9 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.

1.10 Completed 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.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 7

Successful: 7

Scheduled Re-acquisitions: 10

Successful: 10

2.2 FHST Updates:

Scheduled: 18

Successful: 18

2.3 Operations Notes:

The STIS instrument remains in safe mode.

The SSR EDAC error counter was cleared once, per ROP SR-1A.

A 486 table dump was performed at 163/2038Z, using ROP DF-1A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.