Status Report

Hubble Space Telescope Daily Report #2884 – 1 June 2001

By SpaceRef Editor

June 1, 2001

Filed under Hubble Space Telescope, Space Telescope Science Institute, US

HUBBLE SPACE TELESCOPE

DAILY REPORT #2884

PERIOD COVERED: 0000Z (UTC) 05/31/01 – 0000Z (UTC) 06/01/01

Daily Status Report as of 152/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 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.

1.2 Completed Two 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.

1.3 Completed 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 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.

1.5 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.

1.6 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.

1.7 Completed Three Sets of 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. As described in
yesterday’s report and HSTAR 8329, the acquisition for the first iteration
of this proposal defaulted to fine lock backup on one FGS only, possibly
affecting seven observations. Otherwise, there were no other reported
anomalies.

1.8 Completed Five 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.

1.9 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.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 11

Successful: 11

Scheduled Re-acquisitions: 5

Successful: 5

2.2 FHST Updates:

Scheduled: 24

Successful: 24

2.3 Operations Notes:

The Space Telescope Imaging Spectrograph (STIS) remains in safe mode.

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