Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ftp/observing/status_reports/old_reports_01/hst_status_06_07_01 Дата изменения: Thu Jun 7 14:58:00 2001 Дата индексирования: Sun Dec 23 10:20:48 2007 Кодировка: Поисковые слова: crab nebula

HUBBLE SPACE TELESCOPE

DAILY REPORT #2888

PERIOD COVERED: 0000Z (UTC) 06/06/01 - 0000Z (UTC) 06/07/01

Daily Status Report as of 158/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Three 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 Three 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 8634 (Atmospheric Variability on Uranus and Neptune)

The WF/PC-2 was used to obtain snapshot observations of Uranus and
Neptune to monitor changes in their atmospheres on time scales of months to
years. Uranus is rapidly approaching equinox in 2007, with another 4
degrees of latitude in the northern hemisphere becoming visible every
year. Recent HST images during this unique epoch have revealed: {i}
strongly wavelength-dependent latitudinal structure, {ii} the presence of
numerous visible-wavelength cloud features in the northern hemisphere, and,
{iii} in the near-IR, discrete features northward of 25degrees N that have
the highest contrast ever seen for a Uranian cloud. Long-term ground-
based observations show seasonal brightness changes whose origins are not
well understood. Recent IR images of Neptune obtained using adaptive
optics on the Keck Telescope indicate that a new "Bright Companion" type of
feature has recently appeared in the southern hemisphere. Snapshot
observations of these two dynamic planets can supply context in which to
discern the nature of long-term changes in their latitudinal atmospheric
bands and to track the appearance, movement, and disappearance of discrete
albedo features. There were no reported problems.

1.4 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.

1.5 Completed WF/PC-2 8719 (A Continuation Of A Snapshot Survey Of X-
Ray Selected Central Cluster Galaxies)

The WF/PC-2 was used to perform snapshot images of a representative
subset of the central cluster galaxies from an X-ray selected cluster
sample that would provide important constraints on the formation and
evolution of dust in cluster cores that cannot be obtained from
ground-based observations. The observations completed as planned.

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 WF/PC-2 8585 (Cosmological Parameters from Type Ia
Supernovae at High Redshift)

The WF/PC-2 was used to measure the cosmological parameters, Omega,
Lambda, and thus the curvature, Omega_k, using Type Ia supernovae {SNe Ia}
as calibrated standard candles. There were no reported problems.

1.8 Completed Two Sets of 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.

1.9 Completed Three 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.

1.10 Completed WF/PC-2 8815 (Cycle 9 Earth Flats)

The WF/PC-2 was used to monitor flatfield stability. This proposal
obtains sequences of Earth streak flats to construct high quality flat
fields for the WF/PC-2 filter set. These flat fields will allow mapping of
the OTA illumination pattern and will be used in conjunction with previous
internal and external flats to generate new pipeline superflats. The
proposal completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:
Scheduled Acquisitions: 7
Successful: 7

Scheduled Re-acquisitions: 7
Successful: 7

2.2 FHST Updates:
Scheduled: 21
Successful: 21

2.3 Operations Notes:

The Space Telescope Imaging Spectrograph remains in safe mode.

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

Per an operations request, the RF transfer switch 1 and 2 scrub,
which is scheduled every six months, was executed at 157/2033Z.

SSA transmitter #1 was turned on and off at 157/2116Z, per ROP IC-2.

The 486 engineering status buffer limits were adjusted at
158/0902Z, using ROP DF-18A..

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.

/CAW