Hubble Space Telescope Daily Report #2841 – 2 April 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2841

PERIOD COVERED: 0000Z (UTC) 03/31/01 – 0000Z (UTC) 04/02/01

Daily Status Report as of 092/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Five 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 acquisition failure described in 2.1 and HSTAR
8142 occurred during the third iteration of this proposal, affecting four
observations. Otherwise, the proposal completed nominally.

1.2 Completed Two Sets of 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.

1.3 Completed Three Sets of 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.

1.4 Completed Four Sets of 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.

1.5 Completed STIS/CCD 8630 (The Deepest Far-UV Imaging Survey of
Globular Clusters: NGC 6752 and NGC 6397)

The Space Telescope Imaging Spectrograph (CCD) was used to image
the globular clusters NGC 6752 and NGC 6397 in the passband where
cataclysmic variables (CVs) emit most of their radiation: the far UV, and
at Lyalpha. A few very close binaries can drive the dynamical evolution of
an entire globular cluster. CVs should be relatively easy to find in
globular cores with HST, but there is a remarkable dearth of detected CVs
in globular clusters relative to the large numbers predicted by tidal
capture theory. This calls into serious doubt all of our understanding of
globular cluster dynamical evolution. I f most CVs in globular clusters are
much fainter than canonical classical and dwarf novae, then tidal capture
theory can be salvaged. If few or no faint CVs are found, then theorists
will have run out of phase space and simple tidal capture theory will be
shown to have made an incorrect prediction, forcing a major revision in our
theory of tidal capture, and our understanding of globular cluster
dynamical evolution. There were no reported problems.

1.6 Completed Nine 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.

1.7 Completed Two Sets of WF/PC-2 8883 (POMS Test Proposal: WFII Backup
Parallel Archive Proposal II)

The WF/PC-2 was used to complete a POMS test proposal designed to
simulate scientific plans. There were no reported problems.

1.8 Completed WF/PC-2 8826 (Cycle 9 Supplemental Darks pt 1)

The WF/PC-2 was used to perform a T dark calibration program that
obtains three dark frames every day in order to provide data for monitoring
and characterizing the evolution of hot pixels. There were no reported
anomalies.

1.9 Completed WF/PC-2 8773 (Expansion Parallax Distances to Planetary
Nebulae)

The WF/PC-2 was used to observe planetary nebulae {PNe} for which
the lack of reliable distances is especially troubling. Acquired by
generalized statistical methods in all but a handful of cases, individual
PNe distances are often uncertain by factors of two or more. The
observations completed nominally.

1.10 Completed Three Sets of WF/PC-2 8632 (A UV Atlas of Nearby Galaxies)

The WF/PC-2 was used to perform a snapshot survey of local galaxies
at UV wavelengths with the F300W filter. The aim of the project is to
build a reference UV Atlas of normal galaxies, whose optical images are
well known, with the highest possible degree of information, covering all
the morphological types and luminosity classes. The acquisition failure
described in 2.1 and HSTAR 8142 occurred during the third iteration of this
proposal, affecting three observations. Otherwise, the proposal completed
normally.

1.11 Completed Five 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.

1.12 Completed Two Sets of WF/PC-2/STIS/CCD 8679 (Constraining the Age
of the Oldest Stars from the White Dwarf Cooling Sequence in M4)

The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were
used to search for the oldest and hence coolest white dwarfs {WDs} in M4,
the nearest Galactic globular cluster to the Sun. New models for cooling
hydrogen white dwarfs predict that their colors should become bluer, rather
than redder, with increasing age. The goal is to test these models and at
the same time constrain the age of M4. The proposal completed with no
problems.

1.13 Completed WF/PC-2 8719 (A Continuation Of A Snapshot Survey Of X-
Ray Selected Central Cluster Galaxies0

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.

1.14 Completed STIS/CCD/MA1 8606 (Determining the Nature of the
Variable Absorption in AGN: Monitoring NGC 3783 with HST And Chandra)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
investigate Seyfert 1 galaxies, many of which show intrinsic UV absorption
lines, characterized by high moderate widths, significant outflow
velocities, and variability on time scales as small as days. Seyferts with
UV absorption also show variable X-ray “warm absorbers”, characterized by
O VII and O VIII absorption edges, which suggests a common
origin. Variability monitoring is the key to understanding the absorbers,
by providing their radial locations, densities, and evolution in
ionization, column density, velocity, and coverage of the inner active
nucleus. The proposal completed with no problems.

1.15 Completed Two Sets of STIS/CCD 8170 (Kinematics of the Young Star
Clusters and the Gas in the Antennae Galaxies)

The Space Telescope Imaging Spectrograph (CCD) was used to follow
up on the previous discovery of over 1000 young star clusters in “The
Antennae” {NGC 4038} by obtaining long-slit and slitless spectra of a
representative sample of clusters with STIS. These young clusters have the
luminosities, colors, and radii expected of young globular clusters and
must have formed during the ongoing merger. Because of their proximity and
early stage of merging, the disks of NGC 4038 form an ideal laboratory to
study cluster formation in progress. The observations completed nominally.

1.16 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.

1.17 Completed STIS/CCD 8591 (The Smallest Nuclear Black Holes)

The Space Telescope Imaging Spectrograph (CCD) was used to observe
small nuclear black holes which are the last major unexplored part of BH
parameter space, searching for the smallest BHs that HST can possibly
find. The proposal completed with no reported anomalies.

1.18 Completed Two Sets of WF/PC-2 8583 (Imaging Snapshots of Asteroids)

The WF/PC-2 was used to obtain images of the fifty largest main
belt asteroids that have favorable apparitions during cycle 9. The images
will be searched for companion bodies, as well as mineralogical variegation
on the resolved main bodies. There were no reported problems.

1.19 Completed STIS/CCD 8856 (CCD Sensitivity Monitor C9)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the sensitivity of each CCD grating mode to detect any change due to
contamination or other causes. The proposal also monitors the STIS focus
in an imaging mode. There were no anomalies.

1.20 Completed Two Sets of STIS/CCD 8667 (Nuclear Stellar Disks in
Early Galaxies: Black Hole Masses and Disk/Bar/Bulge Evolution)

The Space Telescope Imaging Spectrograph (CCD) was used to image of
an additional four E/SO galaxies to: {1} test whether the unusual
M_bh/M_bulge ratio is typical of these nuclear disk galaxies and {2} search
for additional ring/bar structures will help determine the source of the
accreted material and the time sequence of the disk/bar/bulge/Black Hole
fueling connection. The observations completed with no reported anomalies.

1.21 Completed Six Sets of 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.

1.22 Completed WF/PC-2 8656 (The Hydrogen-Burning Limit in the Globular
Cluster NGC 6397)

The WF/PC-2 was used to perform a major enhancement of an earlier
study of the bottom of the main sequence (MS) of NGC 6397, the globular
cluster with the smallest distance modulus. In the earlier work the lowest
part of the MS had been lost among the numerically dominant field stars;
but accurate astrometry, over a baseline of a few years, now allows an
excellent proper-motion separation of faint cluster stars from the
field. The proposal completed with no reported problems.

1.23 Completed Nine Sets of STIS/CCD 8851 (Sparse Field CTE test {Cycle 9})

The Space Telescope Imaging Spectrograph (CCD) was used to perform
CTE measurements that are made using the “sparse field test”, along both
the serial and parallel axes. The proposal completed with no reported
anomalies.

1.24 Completed STIS/CCD 8711 (C/O Abundance Ratios Across WCL Planetary
Nebulae With Strong PAH And Crystalline Silicate Emission)

The Space Telescope Imaging Spectrograph (CCD) was used to measure
the required high angular resolution across compact nebulae for the crucial
abundance-diagnostic lines of C ii 2326 Angstrom and O ii 2470
Angstrom. ISO has discovered cool O-rich crystalline silicate and water-
ice emission in the far-IR spectra of several planetary nebulae {PNe} which
show very strong hot PAH {polycyclic aromatic hydrocarbon, carbon-rich}
emission bands in their near- and mid-IR spectra. All of these PNe are
young and compact and of low-ionization, and have cool H-deficient Wolf-
Rayet central stars. The correlation with carbon-rich WCL Wolf-Rayet
central stars suggests that the phenomenon is associated with a recent
transition from an O-rich to a C-rich phase by the evolving objects,
following the exposure of 3rd dredge-up enriched material. For these
nebulae, the gas-phase C/O ratios {two of the nebulae have the largest C/O
ratios known} are strongly correlated with the PAH feature strength. The
unexpected discovery of cool oxygen-rich particles around them suggests
that strong C/O abundance gradients may be present in the nebulae. The
observations completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 21

Successful: 20

Per HSTAR 8142, the acquisition scheduled for 090/005128Z failed
when the scan step limit was exceeded on FGS-1. The proposals detailed in
1.1 and 1.10 were affected.

Scheduled Re-acquisitions: 25

Successful: 25

2.2 FHST Updates:

Scheduled: 47

Successful: 47

2.3 Operations Notes:

The SSR EDAC error counter was cleared six times per ROP SR-1A.

The engineering status buffer was maintained twice, using ROP DF-18A.

Using NS-12, the STIS flight software error counter was cleared at
089/1051Z.

As documented in HSTAR 8141, battery #5 impedance (BT5IMPLM)
flagged out-of-limits for the interval 090/004646Z to 090/004759Z.

The STIS MCE-2 reset at 090/022442Z while the low voltage was on
and while in an SAA interval. The STIS flight software error counter was
reset at 090/0229Z per ROP NS-12. MAMA-2 was recovered via normal memory
commanding at 092/0320Z.

A TTR was written for a required re-transmit at 090/0836Z during a
486 load.

The NSSC-1 status buffer was dumped and reset at 090/1451Z as
directed by ROP NS-3.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.