Status Report

Hubble Space Telescope Status Report #2814 22 Feb 2001

By SpaceRef Editor
February 22, 2001
Filed under ,

HUBBLE SPACE TELESCOPE

DAILY REPORT #2814

PERIOD COVERED: 0000Z (UTC) 02/21/01 – 0000Z (UTC) 02/22/01

Daily Status Report as of 053/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed STIS/CCD/MA2 8770 (The Nucleosynthesis of Boron –
Benchmarks for the Galactic Disk)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
determine boron (B) abundance. In spite of several HST cycles of B
abundance determinations, we do not know the true, ambient, present-day
abundance of B. Only two stars {with undepleted Li and Be} have been
observed to derive the Population I true B abundance. Past cycles have
focused on {1} halo stars with low metallicity and {2} solar-type stars
with Li and/or Be deficiencies. In this proposal, the stellar abundances
of B will be determined, measured from the B I 2497 Angstrom line from STIS
echelle spectra, of main sequence F-G stars that have retained their full
initial abundances of boron. Our target stars are those for which
ground-based observations show that beryllium is undepleted. These new
abundances will map evolution of the B abundance in the Galactic disk in
the metallicity range from one-third solar up to solar. Then the B, and
previously determined Li and Be abundances, will be used to improve
understanding of the nucleosynthesis of B. There were no reported anomalies.

1.2 Completed Six Sets of WF/PC-2 8805 (POMS Test Proposal: WFII
Parallel Archive Proposal Continuation)

The WF/PC-2 was used to perform a generic target version of the
WFPC2 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 proposal completed with no reported
problems.

1.3 Completed 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.

1.4 Completed STIS/CCD/MA1 8662 (A Snapshot Survey of the Hot
Interstellar Medium)

The Space Telescope Imaging Spectrograph (CCD And MA1) was used to
obtain snapshot STIS echelle observations of key tracers of hot
interstellar gas {C IV, N IV, and Si IV} for selected FUSE Team O VI survey
targets with known UV fluxes. By taking advantage of the snapshot
observing mode we will efficiently obtain a large number of spectra
suitable for the study of the highly ionized hot component of the
interstellar medium {ISM}. Our goals are to explore the physical
conditions in and distribution of such gas, as well as to explore the
nature of the interfaces between the hot ISM and the other interstellar gas
phases. The observations completed with no reported problems.

1.5 Completed Ten Sets of STIS/CCD 8562 (Probing the Large Scale
Structure: Cosmic Shear Observations)

The Space Telescope Imaging Spectrograph (CCD) was used to probe
the distortion of light bundles from distant galaxies, looking at the
statistical properties of the intervening inhomogeneous {dark} matter
distribution. The proposal completed nominally.

1.6 Completed Two Sets of WF/PC-2 8600 (Dwarf Elliptical Galaxy
Snapshot Survey III)

The WF/PC-2 was used to extend our V and I snapshot survey of
nearby dwarf elliptical {dE} galaxies to include a sample of 30 bright dE
with significant globular cluster {GC} populations. There were no reported
problems.

1.7 Completed Three Sets of STIS/CCD 8837 (CCD Dark Monitor-Part 1)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the darks. The proposal completed with no reported problems.

1.8 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.

1.9 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.

1.10 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.

1.11 Completed WF/PC-2 8705 (External Shear in the Time-Delay Lens RX
J0911+05)

The WF/PC-2 was used to map the mass distribution in the vicinity
of the multiple QSO system RX J0911+05 using weak gravitational
lensing. This object has emerged as one of the most promising candidates
for a cosmological determination of the Hubble constant using time delay
measurements. There is evidence that a high-redshift cluster of galaxies
acts as the source of a very large external shear, affecting the lens
potential. Deep WFPC2 images will allow direct measurement of this shear
from the distortions of faint background galaxies. The proposal completed
with no reported problems.

1.12 Completed Four 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.

1.13 Completed STIS/CCD 8838 (Bias Monitor – Part 1)

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 nominally.

1.14 Completed STIS/CCD/MA2 8627 (Testing Theories Of Wind/Jet
Production In YSOs)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
test theories of jet/wind production from the accretion disks of low-mass
young stellar objects, providing new insight into disk physics, accretion
energy balance, and jet collimation. Observations of the Fe II ultraviolet
lines in absorption will probe lower-density and lower-temperature material
than optical forbidden and permitted emission lines, and thus provide
unique information on jet/wind launching and
acceleration. Velocity-resolved spectra will distinguish between X-wind
models, in which all the mass ejection occurs from the inner disk edge, and
disk wind models, where the flow originates from a much larger area of the
disk. The MCE-2 reset described in 2.3 occurred approximately
three-quarters through this approximate four-hour proposal, possibly
affecting some of the science. Otherwise, the proposal completed
nominally, with no further anomalous activity.

1.15 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.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 8

Successful: 8

Scheduled Re-acquisitions: 6

Successful: 6

2.2 FHST Updates:

Scheduled: 17

Successful: 17

2.3 Operations Notes:

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

The STIS MCE-2 reset at 053/011037Z while the high voltage was on
but while outside any SAA interval. MAMA-2 was recovered via normal SMS
commanding at 053/0115Z. The proposal described in 1.14 may have been
affected. The STIS flight software error counter was cleared at 053/0128Z
per ROP NS-12.

The NSSC-1 status buffer was dumped and reset at 053/0517Z as
directed by ROP NS-3.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.

SpaceRef staff editor.