Status Report

Hubble Space Telescope Daily Report #2853 – 18 Apr 2001

By SpaceRef Editor
April 18, 2001
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PERIOD COVERED: 0000Z (UTC) 04/17/01 – 0000Z (UTC) 04/18/01

Daily Status Report as of 108/0000Z


1.1 Completed Two Sets of STIS/CCD 8864 (CCD Dark Monitor-Part 2)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the darks for the CCD. The proposal completed nominally.

1.2 Completed WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)

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 nominally.

1.3 Completed STIS/CCD/MA1 8582 (UV Detectability of Bright Quasars in
the Sloan Fields)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
examine the He II Ly alpha absorption at 304{1+z} Angstrom which is a far
more sensitive tracer of the intergalactic medium {IGM} than its H I
counterpart. The recent detections of such absorption in four quasars,
albeit with limited data quality and a small sample size, demonstrate the
great potential of such a probe. There were no reported problems.

1.4 Completed WF/PC-2 7407 (Continuation of Temporal Monitoring of the
Crab Synchrotron Nebula)

The WF/PC-2 was used to observe the synchrotron nebula surrounding
the Crab pulsar that has been the subject of intensive study for
decades. It is generally accepted that the structure and activity in this
region are due to wave phenomena near the termination shock of the pulsar
wind, observations of which hold unique promise of leading to more complete
models of the pulsar and its magnetosphere. Unfortunately, this promise
has not been fulfilled, largely because of the low spatial resolution and
uneven temporal coverage of existing studies. Recent WF/PC-2 observations
of the Crab synchrotron nebula offer new hope in this quest. These data,
which reach the natural size scale defined by the Larmor radius of
energetic electrons, resolve the majority of the known features in the
Crab. For the first time it is possible to reliably establish the physical
conditions {e.g., emissivities, equipartition fields, and pressures} of
features associated with the wind and its termination shock. The
observations completed as planned.

1.5 Completed Four Sets of STIS/CCD 9248 (Probing the Large Scale
Structure: Cosmic Shear Observations)

The Space Telescope Imaging Spectrograph (CCD) was used to measure
the distortion of light bundles from distant galaxies that probe the
statistical properties of the intervening inhomogeneous {dark} matter
distribution. Its tidal gravitational field distorts the observable image
shapes thereby causing a coherent ellipticity pattern {Cosmic Shear}. The
observations completed nominally.

1.6 Completed FGS/1 9240 (Astrometric Mass Determination of an
Extrasolar Planet Candidate)

Fine Guidance Sensor-1R was used to perform astrometric
observations that will allow a quick measure of the sky-plane motion of 55
Cancri, a G star with an Msin{i} = 0.9 MJ radial velocity companion with a
14 day period. By using 7 pairs of visits, where each visit within a pair
has the same parallax factor, we will be able to accurately determine the
stars’s proper motion. The reflex motion of the star, due to its orbit
about the star-companion barycenter, will manifest itself as a systematic
residual to the measured proper motion if the companion is sufficiently
massive. There were no reported problems.

1.7 Completed 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

1.8 Completed WF/PC-2 8683 (Imaging Of Brightest Cluster Galaxies: The
High End Of The Black Hole Mass Distribution)

The WF/PC-2 was used to make kinematic black hole detections in
galaxies to decide whether they indicate that the mass correlates with both
optical luminosity and radio power. The observation completed with no
reported problems.

1.9 Completed WF/PC-2 8677 (Extragalactic Novae: the Maximum Magnitude
– Rate of Decline Relation in NGC 4472)

The WF/PC-2 was used to accomplish two goals: {1} to provide the
first homogeneous observational constraints on theoretical models for novae
outbursts; and {2} to assess the reliability of novae as standard candles
by using WFPC2 to collect well sampled light curves for 20-50 novae in the
supergiant elliptical galaxy NGC 4472, the brightest galaxy within 30
Mpc. Both the length of the observing window and the temporal sampling of
the observations are specifically designed to ensure that the novae peak
magnitudes and decline rates are measured accurately. These data will be
used to construct the first `Maximum Magnitude versus Rate of Decline’
{MMRD} relation for a galaxy beyond the Local Group. This relation is not
only a potentially powerful standard candle, but its shape and dispersion
are directly linked to physical parameters which govern the physics of
novae outbursts such as the white dwarf mass, temperature and mass
accretion rate. The proposal completed with no reported problems.

1.10 Completed STIS/CCD 8607 (Completing the Local AGN Inventory: The
AGN Content of Composite Nuclei)

The Space Telescope Imaging Spectrograph (CCD) was used to increase
the knowledge of the local space density of AGNs which is of fundamental
importance to a number of astrophysical problems. A significant fraction
of nearby galaxies have nuclei whose spectra are intermediate between those
of LINERs and nuclear starbursts. These “transition objects” may be
composite systems that contain both a central AGN and circumnuclear star
formation. We will test this hypothesis by obtaining spatially-resolved
optical spectra of a well-defined sample of 15 nearby transition nuclei
selected from the extensive ground-based survey of Ho, Filippenko, and
Sargent. The observations completed with no reported problems.

1.11 Completed STIS/CCD 8865 (Bias Monitor-Part 2)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at
gain = 4, to build up high-S/N superbiases and track the evolution of hot
columns. The proposal completed with no anomalous activity.

1.12 Completed STIS/CCD 8619 (Critical Spectroscopic Variations In Eta

The Space Telescope Imaging Spectrograph (CCD) was used to observe
the very massive, unstable, persistently enigmatic star Eta Carinae that
has implications for several branches of astrophysics. While HST has
produced a series of remarkable discoveries concerning this object, the
nature of the central star remains elusive. Now, however, recent
developments offer, for the first time, an approach that can settle certain
long-standing questions which have been obstacles to understanding this
unique object. A 5.5-year spectroscopic and X-ray cycle has been
confirmed. STIS now provides the most promising and very likely the only
way to test whether Eta Car is a 5.5-yr binary system. If it is, STIS will
also allow us to constrain the parameters, needed to assess the companion
star’s possible role in past outbursts and ejecta. If the data conflict
with binary models, then the 5.5-yr effect is probably a thermal cycle
which will give novel information about the star’s structure. In addition
to the periodicity, a large, almost unprecedented brightening, first
noticed in HST data, has occurred since 1997 and merits followup
observations. The observations completed with no reported problems.

1.13 Completed WF/PC-2 8824 (Decontaminations and Associated
Observations Pt. 3/4)

The WF/PC-2 was used for the monthly WFPC2 decons. Also included
are instrument monitors tied to decons: photometric stability check, focus
monitor, pre- and post-decon internals {bias, intflats, kspots, & darks},
UV throughput check, VISFLAT sweep, and internal UV flat check. There were
no reported problems.

1.14 Completed STIS/CCD/MA1 8638 (Temperature Scale And Metal
Abundances Of Hot Hydrogen-Rich Central Stars Of Planetary Nebulae)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
perform UV spectroscopy on a sample of hot hydrogen-rich central stars of
PNe, covering the hottest phase of post-AGB evolution. The spectra will
then be analyzed with fully metal line blanketed NLTE model atmospheres in
order to determine T_eff, surface gravity, and chemical composition. The
proposal completed with no reported problems.


2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 10

Successful: 10

Scheduled Re-acquisitions: 3

Successful: 3

2.2 FHST Updates:

Scheduled: 18

Successful: 18

2.3 Operations Notes:

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

A TTR was written when a command dropout occurred at 108/083613Z
during a load uplink, necessitating a re-transmit.

A CCS engineering status buffer limit was adjusted at 108/0844Z as
directed by ROP DR-18A.


Continuation of normal science observations and calibrations.

SpaceRef staff editor.