Hubble Space Telescope Daily Report #2961 – 21 Sep 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2961

PERIOD COVERED: 0000Z (UTC) 09/20/01 – 0000Z (UTC) 09/21/01

Daily Status Report as of 264/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed WF/PC-2/STIS/CCD 9174 (Using Optically Faint Radio
Sources to Pinpoint Dusty Proto-Galaxies)

The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were
used to observe a number of high redshift, dusty starburst galaxies that
remain invisible in ground based in the Hubble Deep Field. These galaxies
appear as faint radio sources with bright submillimeter counterparts,
demonstrating they are very dusty systems. The luminosities of these
galaxies suggest they are in the process of converting the bulk of their
gas mass into stars, and will likely evolve into present day massive
ellipticals. The observations completed normally, with no reported problems.

1.2 Completed Three Sets of WF/PC-2 8936 (Cycle 10 Supplemental Darks
Pt1/3)

The WF/PC-2 was used to perform a dark calibration program that
obtains 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 STIS/CCD 9088 (Next Generation Spectral Library of Stars)

The Space Telescope Imaging Spectrograph (CCD) was used to produce
a “Next Generation” Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters by using the low dispersion UV
and optical gratings of STIS. The library will be roughly equally divided
among four metallicities, very low {Fe/H < -1.5}, low {-1.5 < Fe/H < -0.5}, near-solar {-0.5 < Fe/H < 0.1}, and super-solar {Fe/H > 0.1}, well-sampling
the entire HR-diagram in each bin. Such a library will surpass all extant
compilations and have lasting archival value, well into the Next Generation
Space Telescope era. No problems occurred.

1.4 Completed STIS/CCD 8903 (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. There were no problems.

1.5 Completed FGS/1 9168 (The Distances to AM CVn Stars)

Fine Guidance Sensor (FGS) #1 was used to determine the parallaxes
and proper motions of the five brightest of the seven known AM CVn
systems. AM CVn systems are binaries where mass is transferred from a
completely hydrogen-deficient, degenerate mass donor to a white dwarf
primary through a helium accretion disk. A better understanding of these
systems is crucial for a number of reasons: (1) to study the late stages of
binary evolution, (2) to study the effect of chemical composition on the
physics of accretion discs, (3) to estimate their contribution to the
Supernovae Ia rate, and (4) to estimate their contribution to the
gravitational radiation background. All observations completed with no
reported problems.

1.6 Completed Seven 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 STIS/CCD 8901 (Dark Monitor-Part 1)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the darks. There was no anomalous activity.

1.8 Completed STIS/CCD/MA1 8615 (Ultraviolet Spectroscopy of R Coronae
Borealis Stars — Broad Lines from an Accretion Disc?)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
obtain spectra of three R Coronae Borealis {RCB} stars that will provide
novel data on hot gas near these stars.
RCBs are hydrogen-deficient and fade at unpredictable times as a carbon
soot cloud obscures the star. Optical spectra taken when a star has faded
reveal an emission line spectrum containing sharp and broad lines. The
latter are of much higher excitation than the former. For RCB, it has been
suggested that the broad lines arise from an accretion disk around a
compact secondary. These optical lines are visible only during the
infrequent extreme fadings of a RCB. The observations completed as planned.

1.9 Completed STIS/CCS/MA2 9048 (Boron Constraints on Slow Mixing in
Low Mass Stars)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
observe the atomic and nuclear characteristics of the light elements Li, Be
and B, that make their photospheric abundances ideal tracers of internal
physical processes in stars. Both Li and Be have been heavily utilized to
this end since their diminished abundances are a direct result of the
extent of internal slow mixing between surface and interior layers, as has
been shown with ground-based data. Boron provides a fresh and special
probe because it survives to greater depths inside stars than does Li or
Be, and can thus uniquely reveal the depth of mixing. It is proposed to
observe B in stars with very large depletions of Li and Be, i.e. stars
which have been the most seriously affected by mixing. No problems occurred.

1.10 Completed STIS/CCD/MA1 8880 (EV Lac)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
perform four orbits of E140M spectroscopy in the time-tag mode of the
active red dwarf star EV Lac, in conjunction with a 100 ks Chandra HETGS
pointing. EV Lac is an excellent candidate for dispersed X-ray
spectroscopic studies owing to its brightness and propensity for frequent
and extreme variability. The proposal completed, and no anomalous activity
was reported.

1.11 Completed Three 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.

1.12 Completed STIS/CCD 9148 (Light Echos and the Nature of Type Ia
Supernovae)

The Space Telescope Imaging Spectrograph (CCD) was used to take
STIS snapshot images of a subset of 43 well observed Type Ia supernovae
{SNIa}, most of which have been discovered in late type galaxies over the
last 40 years to make a systematic search for light echos around SN
Ia. STIS will also observe a sample of 10 SN II and SN Ib/c, which are
believed to be the result of massive star core collapse and, therefore, to
be thin-disk population objects, in order to make an empirical calibration
of the accuracy of our method for determining scale heights. The SN Ia
sample will provide a direct as well as accurate estimate of the scale
height of SN Ia which is an important clue to the progenitors of these
events. The proposal completed nominally.

1.13 Completed STIS/CCD 9285 (POMS Test Proposal: STIS Non-scripted
Parallel Proposal Continuation III)

The Space Telescope Imaging Spectrograph (CCD) was used to make low
galactic latitude, non-scripted parallel observations as part of a POMS
test proposal. The observations were completed as planned, and no
anomalies were reported.

1.14 Completed WF/PC-2 9155 (The Cepheid Distance to NGC 1637: A Direct
Comparison with the EPM Distance to SN 1999em)

The WF/PC-2 was used to directly compare distances estimated by two
primary extragalactic distance indicators. T he appearance of supernova
1999em, a bright, extremely well- observed type II plateau event in the
nearby SBc galaxy NGC 1637 offers the best chance to test the consistency
of the Expanding Photosphere Method {EPM} of supernova distance
determination with that derived from Cepheid variable stars. Although EPM
distances have been measured to 18 type II supernovae out to 180 Mpc and
used to determine Hubble’s constant independent of the Cepheid distance,
there have never been any measurements of Cepheids in a galaxy that has
hosted a normal type II-P supernova, the classic variety of core-collapse
event to which EPM-derived distances are most robust. The proposal
completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 11

Successful: 11

Scheduled Re-acquisitions: 5

Successful: 5

2.2 FHST Updates:

Scheduled: 23

Successful: 23

2.3 Operations Notes:

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

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.