Hubble Space Telescope Daily Report #2891 – 12 June 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2891

PERIOD COVERED: 0000Z (UTC) 06/11/01 – 0000Z (UTC) 06/12/01

Daily Status Report as of 163/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Three Sets of 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.

1.2 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.

1.3 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.

1.4 Completed 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.

1.5 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.

1.6 Completed Two 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 2.1 and
HSTAR 8241, the acquisition for the initial iteration of this proposal
defaulted to fine lock backup on one FGS only, possibly affecting five
observations. There were no other reported anomalies.

1.7 Completed S/C 5582 (FOC/48 Monthly Activation (Camera Section
Only): Cycle 4)

This proposal was executed as scheduled, and no anomalies were noted.

1.8 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.

1.9 Completed WF/PC-2 8644 (Galaxy Recycling in Clusters)

The WF/PC-2 was used to obtain deep B, V, and I images of two
unusual, extended, low surface brightness plumes of material recently
discovered in the Coma and Centaurus clusters. These plumes are most
likely transient tidal debris resulting from the destruction of galaxies as
they passed through the cores of these clusters. Over time, this debris
will spread throughout the cluster potential, augmenting the intergalactic
populations of stars, globular clusters, dwarf galaxies, and gas. Some of
this material may also be incorporated into the halos of the central
dominant galaxies. There were no reported problems.

1.10 Completed FOC/96 7923 (FOC F/96 Turn-on)

The Faint Object Camera (f/96) was used to take an internal flat
and a dark to ensure that the 30-day limit for the FOC is not
exceeded. The observations were executed as scheduled, and no anomalies
were noted.

1.11 Completed Two Sets of WF/PC-2 8812 (Cycle 9 Internal Monitor)

The WF/PC-2 was used to obtain routine internal monitors for WFPC2
in order to monitor the health of the cameras. A variety of internal
exposures are obtained in order to provide a monitor of the integrity of
the CCD camera electronics in both bays {gain 7 and gain 15}, a test for
quantum efficiency in the CCDs, and a monitor for possible buildup of
contaminants on the CCD windows. There were no reported problems.

1.12 Completed FGS/1 9171 (High Speed Photometry of the Transiting
Planet HD 209458b)

Fine Guidance Sensor #1 was used to observe HD 209458b, the only
extrasolar giant planet {EGP} detected that has an orbit inclined enough
toward the Sun for the transits to be detected. Differential photometry
with respect to comparison stars showed a transit depth of 1.5 a transit
time of 3.2 hours. Transit ingress and egress are ~25 minutes in duration
suggesting the planet transits along a short chord instead of the full
stellar disk. It is proposed to observe the transit ingress {1-orbit} and
egress {1-orbit} with a FGS used as a high- speed photometer. The proposal
completed with no reported problems.

1.13 Completed Three Sets of WF/PC-2 9244 (POMS Test Proposal: WFII
Parallel Archive Proposal Continuation)

The WF/PC-2 was used to perform a generic target version of the
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 observations completed with no anomalous
activity.

1.14 Completed Two 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.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 9

Successful: 9

Per HSTAR 8241, the acquisition at 162/1110Z defaulted to fine lock
backup on FGS-1 only when the scan step limit was exceeded on FGS-2. The
proposal detailed in 1.6 may have been affected.

Scheduled Re-acquisitions: 8

Successful: 8

2.2 FHST Updates:

Scheduled: 20

Successful: 20

2.3 Operations Notes:

The Space Telescope Imaging Spectrograph is in safe mode.

The SSR EDAC error counter was cleared four times, using ROP SR-1A.

On two occasions, per ROP DF-18A, the engineering status buffer
limits were adjusted.

The ephemeris table was uplinked at 163/0036Z as directed by ROP
DF-07A.

Using ROP RD-7A, ESTR reconditioning was performed at 163/0753Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.