Status Report

NASA Hubble Space Telescope Daily Report # 3385

By SpaceRef Editor
June 17, 2003
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HUBBLE SPACE TELESCOPE

DAILY REPORT # 3385

PERIOD COVERED: DOY 167

OBSERVATIONS SCHEDULED

NICMOS 8791

NICMOS Post-SAA calibration – CR Persistence Part 2

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

STIS 9049

Boron in G64-12: Higher Big Bang Lithium or Signature of the Nu-Process?

The extremely metal-poor { Fe/H ~ -3.3 } star G64-12 shows a
remarkable lithium {Li} abundance that is about 2 times larger than
those seen in other warm metal-poor stars, from which the Big Bang Li
abundance is inferred. This star’s enhanced Li has resulted from
either 1. Galactic Li enrichment from a lower Big Bang value, or 2.
stellar depletion from a higher Big Bang value, with significant
cosmological implications. We argue against two of the three prominent
mechanisms of Galactic Li enrichment, leaving the theoretical
Nu-process in Type II supernovae as the sole viable mechanism. This
mechanism’s crisp signature is the concomitant production of copious
amounts of boron {B}; if the Nu-process enriched the material out
which G64-12 formed with the extra Li observed today, then this star
should also exhibit a large detectable B overabundance. B in G64-12
can only be observed from space, using HST/STIS. If this star’s
STIS-based B abundance lies above the established B-Fe trend, this
would be the first observational evidence for the Nu-process. But if
its B abundance lies near the B-Fe trend, this would provide direct
evidence that G64-12 is an elusive fossil of a Big Bang Li abundance
about 0.3 dex above currently favored values, providing consistency in
standard Big Bang Nucleosynthesis between Li and D {but not 4He}.
EITHER RESULT would be of fundamental importance to Astronomy.

ACS 9401

The ACS Virgo Cluster Survey

We propose the most comprehensive imaging survey to date of
low-redshift, early-type galaxies. Our goal is to exploit the
exceptional imaging capabilities of the ACS by acquiring deep images
— in the SDSS g^ and z^ bandpasses — for 163 E, S0, dE, dE, N and
dS0 galaxies in Virgo, the nearest rich cluster. This extraordinary
dataset would likely constitute one of the principal legacies of HST,
and would have widespread applications for many diverse areas of
astrophysics. Our immediate scientific objectives are threefold: {1}
measure metallicities, ages and radii for the many thousands of
globular clusters {GCs} in these galaxies, and use this information to
derive the protogalactic mass spectrum of each galaxy; {2} measure the
central luminosity and color profile of each galaxy, and use this
information to carry out a completely independent test of the merging
hierarchy inferred from the GCs, with the aid of N-body codes that
simulate the merger of galaxies containing massive black holes; and
{3} calibrate the z^ -band SBF method, measure Virgo’s 3-D structure,
and carry out the definitive study of the GC luminosity function’s
precision as a standard candle. Our proposed Virgo Cluster Survey will
yield a database of unprecedented depth, precision and uniformity, and
will enable us to study the record of galaxy and cluster formation in
a level of detail which will never be possible with more distant
systems.

NICMOS/STIS CCD 9405

The Origin of Gamma-Ray Bursts

The rapid and accurate localization of gamma-ray bursts {GRBs}
promised by a working HETE-2 during the coming year may well
revolutionize our ability to study these enigmatic, highly luminous
transients. We propose a program of HST and Chandra observations to
capitalize on this extraordinary opportunity. We will perform some of
the most stringent tests yet of the standard model, in which GRBs
represent collimated relativistic outflows from collapsing massive
stars. NICMOS imaging and STIS CCD spectroscopy will detect broad
atomic features of supernovae underlying GRB optical transients, at
luminosities more than three times fainter than SN 1998bw. UV,
optical, and X-ray spectroscopy will be used to study the local ISM
around the GRB. Chandra spectroscopy will investigate whether the GRB
X-ray lines are from metals freshly ripped from the stellar core by
the GRB. HST and CTIO infra-red imaging of the GRBs and their hosts
will be used to determine whether `dark’ bursts are the product of
unusually strong local extinction; imaging studies may for the first
time locate the hosts of `short’ GRBs. Our early polarimetry and
late-time broadband imaging will further test physical models of the
relativistic blast wave that produces the bright GRB afterglow, and
will provide unique insight into the influence of the GRB environment
on the afterglow.

ACS/WFC 9419

The Complete IMF of a Massive Young Cluster

We propose to use the large improvement in sensitivity and wide-field
resolution provided by ACS to obtain for the first time the complete ~
0.1 M_Sun to ~ 100 M_Sun IMF of a single massive young cluster. We
will obtain BVI + nebular deep {V ~ 27} WFC photometry of six cluster
and one background pointings and we will use the auto-parallel
capacity of ACS to simultaneously acquire deep NUV+U+V photometry of
selected regions in the cluster. Special care has been taken to treat
all the complications which arise in the reduction of data for the
purpose of calculating the IMF of a young cluster. We have chosen as
our object of study N11 in the LMC because it arguably provides the
best combination of stellar mass range {> 40 O stars, with several O3
stars}, spatial resolution {1 WFC pixel = 0.0125 pc}, low extinction
{E{B-V} ~ 0.1}, crowding, background confusion, and nebular
contamination in comparison to other Galactic and Local Group
clusters. It also has the advantage of having two separate regions,
one which has already stopped forming stars and another one which is
still forming them, thus allowing us to search for differences in the
IMF between those two cases. The ACS data will be complemented with IR
ground-based observations obtained using Gemini South, for which we
already have been awarded time.

ACS 9482

ACS Pure Parallel Lyman-Alpha Emission Survey {APPLES}

Ly-alpha line emission is an efficient tool for identifying young
galaxies at high redshift, because it is strong in galaxies with young
stars and little or no dust — properties expected in galaxies
undergoing their first burst of star- formation. Slitless spectroscopy
with the ACS Wide-Field Camera and G800L grism allows an unmatched
search efficiency for such objects over the uninterrupted range 4 <~ z
<~ 7. We propose the ACS Pure Parallel Ly-alpha Emission Survey
{“APPLES”}, to exploit this unique HST capability and so obtain the
largest and most uniform sample of high redshift Ly-alpha emitters
yet. Parallel observations will allow this survey to be conducted with
minimal impact on HST resources, and we will place reduced images and
extracted spectra in the public domain within three months of
observation. We aim to find ~ 1000 Ly-alpha emitters, 5 times the
biggest current sample of Ly-alpha emitters. This unprecedented sample
will provide robust statistics on the populations and evolution of
Ly-alpha emitters between redshifts 4–7; a robust measurement of the
reionization redshift completely independent of the Gunn-Peterson
trough; spatial clustering information for Ly-alpha emitters which
would let us probe their bias function and hence halo mass as a
function of redshift; many galaxies at redshift exceeding 6; and lower
redshift serendipitous discoveries.

NICMOS 9485

Completing A Near-Infrared Search for Very Low Mass Companions to
Stars within 10 pc of the Sun

Most stars are fainter and less massive than the Sun. Nevertheless,
our knowledge of very low mass {VLM} red dwarfs and their brown dwarf
cousins is quite limited. Unknown are the true luminosity function
{LF}, multiplicity fraction, mass function, and mass-luminosity
relation for red and brown dwarfs, though they dominate the Galaxy in
both numbers and total mass. The best way to constrain these relations
is a search for faint companions to nearby stars. Such a search has
several advantages over field surveys, including greater sensitivity
to VLM objects and the availability of precise parallaxes from which
luminosities and masses can be derived. We propose to complete our
four-filter NICMOS snapshot search for companions to stars within 10
pc. With a 10 sigma detection limit of M_J ~ 20 at 10 pc, we can
detect companions between 10 and 100 AU that are at least 9 mag
fainter than the empirical end of the main sequence and at least 6.5
mag fainter than the brown dwarf Gl 229B. When completed, our search
will be the largest, most sensitive, volume-limited search for VLM
companions ever undertaken. Our four-filter search will permit
unambiguous identification of VLM-companion candidates for follow-up
observation. Together with IR speckle and deep imaging surveys, our
program will firmly establish the LF for VLM companions at separations
of 1-1000 AU and the multiplicity fraction of all stars within 10 pc.

WFPC2 9589

WFPC2 Decontaminations and Associated Observations Pt. 1/3

This proposal is 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.

WFPC2 9595

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt3/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels.

STIS 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9608

CCD Bias Monitor – Part 2

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.

STIS 9615

Cycle 11 MAMA Dark Monitor

This test performs the routine monitoring of the MAMA detector dark
noise. This proposal will provide the primary means of checking on
health of the MAMA detectors systems through frequent monitoring of
the background count rate. The purpose is to look for evidence of
change in dark indicative of detector problem developing.

STIS 9633

STIS parallel archive proposal – Nearby Galaxies – Imaging and
Spectroscopy

Using parallel opportunities with STIS which were not allocated by the
TAC, we propose to obtain deep STIS imagery with both the Clear
{50CCD} and Long-Pass {F28X50LP} filters in order to make
color-magnitude diagrams and luminosity functions for nearby galaxies.
For local group galaxies, we also include G750L slitless spectroscopy
to search for e.g., Carbon stars, late M giants and S-type stars. This
survey will be useful to study the star formation histories, chemical
evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.

ACS 9674

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

This is the default archival pure parallel program for STIS during cycle
11.

WFPC2 9709

POMS Test Proposal: WFII parallel archive proposal

This is the 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 2002 Parallels
Working Group.

ACS 9984

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground
mass provide a powerful method of directly measuring the amount and
distribution of dark matter. Several groups have recently detected
this weak lensing by large-scale structure, also called cosmic shear.
The high resolution and sensitivity of HST/ACS provide a unique
opportunity to measure cosmic shear accurately on small scales. Using
260 parallel orbits in Sloan textiti {F775W} we will measure for the
first time: beginlistosetlength sep0cm setlengthemsep0cm setlength
opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em the
skewness of the shear distribution, and em the magnification effect.
endlist Our measurements will determine the amplitude of the mass
power spectrum sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20,
and the mass density Omega_m with s/n=4. They will be done at small
angular scales where non-linear effects dominate the power spectrum,
providing a test of the gravitational instability paradigm for
structure formation. Measurements on these scales are not possible
from the ground, because of the systematic effects induced by PSF
smearing from seeing. Having many independent lines of sight reduces
the uncertainty due to cosmic variance, making parallel observations
ideal.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None

COMPLETED OPS REQs: None

OPS NOTES EXECUTED: None

                         SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              8                         8
FGS REacq              9                         9
FHST Update            15                       15
LOSS of LOCK

SIGNIFICANT EVENTS:

An intercept SMS (SA167N03) is anticipated to be released early
today. First uplink opportunity is approximately 168/19:00Z,
intercept time is 169/03:58Z. SMS will include a GENSLEW with the
text block missing, OPUS will provide the missing data (required by
the SI console) in the GENSLEW Ops Request.

VEST-SIMSS to STOCC-CCS Interface Testing and Validation scheduled
168/10:00Z – 20:00Z with GDOC, HITT, SE, SOC, and VEST using CCS "B"
String and PRD O06100TR1. The purpose of this testing is to verify
functionality of the SIMSS Interface between the VEST Structure and
the STOCC CCS.

SpaceRef staff editor.