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HST Daily Report #3396



 
 
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Old July 2nd 03, 10:29 PM
Jacques van Oene
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Default HST Daily Report #3396

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3396

PERIOD COVERED: DOY 182

OBSERVATIONS SCHEDULED

STIS 9359

The Old Star CS 31082-001, the Age of the Universe, and the Nature of the
r-process

We propose to observe the newly discovered r-process-element enhanced star,
CS
31082-001 {Fe/H ~ -2.9}, in order to determine abundances of the heaviest
stable
elements, using absorption lines that are only reachable in the near UV.
This
star is the only halo star for which a uranium detection has been reported,
and
for which the U/Th chronometer has been used to specify an age limit. In
order
to improve the accuracy of the age determination from U/Th we require
abundance
estimates of the daughter nuclides --Pb & Bi-- for which only upper limits
have
been obtained from ground-based observations. Such estimates will provide
crucial constraints on the initial production ratio of U/Th, resulting in a
more
strict lower limit on the age of this star's progenitor, hence on the age
of the
Universe. Measurements of 3rd-peak neutron-capture elements, such as Pt,
Os, Ir,
and Au, all with lines in the 2400-3100 Angstrom range, will expand our
knowledge of element synthesis in the early Galaxy. Our recent ESO-VLT data
indicate that the neutron-capture elements in this star exhibit different
enhancements as compared with the previously known `` r-process star'' CS
22892-052, an apparent anomaly that must be resolved. CS 31082-001 is the
ideal
HST target in its class -- it is 4-times brighter than CS 22892-052, and
less
affected by molecular line blending. Consequently, these HST data will
become
the reference in all future studies of similar stars.

STIS/FUV 9412

The Physical Parameters of the Hottest, Most Luminous Stars as a Function of
Metallicity

We have obtained excellent, new ground-based blue optical and HAlpha spectra
of
a sample of very early-type stars in the Magellanic Clouds in order to
measure
their physical properties, for comparison with the extensive data that
exists
for higher-metallicity Galactic stars. Our aim is to understand how
effective
temperatures depend upon metallicity {necessary in determining IMFs}, and to
explore the astrophysically interesting regime of stars of extreme
temperatures,
masses, and luminosities. In order to do this, we need to measure the
stellar
wind terminal velocities for our stars, necessary to constrain the stellar
models. These can only be measured with STIS/FUV on HST. In addition, we
will
obtain higher spatial resolution data on the HAlpha line for stars for which
nebular contamination is significant in our ground-based data. We also
include
several R136 stars with excellent STIS/CCD data but which lack UV line
measures.
These new HST data will provide important information about the strengths of
stellar winds at extreme luminosities and the calibration of the Wind
Momentum-
Luminosity Relationship at lower metallicities. This proposal was highly
rated
in Cycle 9, but only 4 snapshots were obtained. We have completed the
analysis
of these plus additional data from the archives, but need spectra of the
remaining objects if we are to answer the questions we pose.

SNAP/STIS 9434

A SNAPSHOT Survey of the Hot Interstellar Medium

We propose to obtain SNAPSHOT STIS echelle observations of key tracers of
hot
interstellar gas {CIV, NV and SiIV} for selected FUSE Team OVI 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. Using inter--comparisons of the various ionic
ratios
for CIV, NV, OVI and SiIV, we will be able to discriminate between the
various
models for the production of the highly ionized gas in the Galactic ISM. The
survey will also enable detailed studies of regions already known to
contain hot
gas through X-ray emission measurements {e.g., SNRs and radio loops}. The
proposed SNAPSHOT observations will extend our previous Cycle 9 survey
{which
was compromised by the STIS side 1 failure}, and should roughly double the
number of stars for which high quality STIS observations of the important
hot
gas tracers are available, enabling us to derive a truly global view of the
hot
ISM.

ACS 9462

Systemic and Internal Proper Motions of the Magellanic Clouds from
Astrometry
with ACS

We request first epoch observations with ACS of Magellanic Cloud fields
centered
on background quasars. Second epoch observations will be requested ~ 5 years
later to allow the measurement of the systemic and internal proper motions
of
the Clouds with error ~0.05 mas/year. These motions are of fundamental
importance. The systemic motions of the LMC and SMC probe the gravitational
potential of the dark halo. The internal proper motion due to rotation can
be
exploited to yield a rotational parallax distance to the LMC; the first time
that this will be done for any galaxy. This is particularly important for
the
LMC because of its crucial role in the extragalctic distance ladder.
Previous
measurements of the proper motion of the LMC yield a systemic component
ranging
from 1.4 mas/year to 3.4 mas/year {differing by several times the quoted
errors}, with no useful determination of the internal motions. The main
problem
with measurements of the proper motion of the LMC has been the lack of a
sample
of background quasars to use as reference frame. We have recently been able
to
identify a sample of 54 quasars behind the Magellanic Clouds from their
variability characteristics in the MACHO database. With this sample and the
advent of ACS an accurate proper motion measurement has become possible for
the
very first time.

ACS 9472

A Snapshot Survey for Gravitational Lenses among z = 4.0 Quasars

Over the last few years, the Sloan Digital Sky Survey has revolutionized the
study of high-redshift quasars by discovering over 200 objects with redshift
greater than 4.0, more than doubling the number known in this redshift
interval.
The sample includes eight of the ten highest redshift quasars known. We
propose
a snapshot imaging survey of a well-defined sample of 250 z 4.0 quasars in
order to find objects which are gravitationally lensed. Lensing models
including
magnification bias predict that at least 4% of quasars in a flux-limited
sample
at z 4 will be multiply lensed. Therefore this survey should find of order
10
lensed quasars at high redshift; only one gravitationally lensed quasar is
currently known at z 4. This survey will provide by far the best sample to
date of high-redshift gravitational lenses. The observed fraction of lenses
can
put strong constraints on cosmological models, in particular on the
cosmological
constant Lambda. In addition, magnification bias can significantly bias
estimates of the luminosity function of quasars and the evolution thereof;
this
work will constrain how important an effect this is, and thereby give us a
better understanding of the evolution of quasars and black holes at early
epochs, as well as constrain models for black hole formation.

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 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 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and
1x1
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 9657

ACS Internal Flat Field Stability

The flat field stability and characterization obtained during the ground
calibration and SMOV phases will be tested and verified through a sub-sample
of
the filter set. Only internal exposures with the calibration lamps will be
required.

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.

WFPC2 9710

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

ACS/HRC 9805

OGLE-TR-56b: The Most Interesting Transiting Planet

Our team has recently succeeded in confirming spectroscopically the
discovery of
the first extrasolar giant planet found in a transit search: OGLE-TR-56b.
Its
main parameters a mass = 0.9 Jupiters, size = 1.3 Jupiters. Thus,
OGLE-TR-56b
appears to be similar to HD 209458b, the only other known transiting giant
planet. Unfortunately, our planet radius determination is uncertain due to
the
very limited precision of the ground-based photometry, and does not allow
for a
meaningful comparison with theoretical model predictions. We propose HST
observations with the ACS-HRC of the main transit of OGLE-TR-56b, which will
improve the precision and the accuracy of the planet parameters by close to
a
factor of 10. In addition, we propose a timing experiment for the planet's
extremely close orbit {1.2-day period, 0.023 AU from the star}, which will
allow
us to detect the orbital decay and test convection theories.

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.)

HSTAR 9067: GS Acquisition (3,2,3) @ 182/09:45:05Z resulted in FL backup
on FGS 3. HST was
in LOS at time of event, upon AOS, there were no FGS
flags indicating SRLEX or
SSLEX. Under investigation.

HSTAR 9069: GS Acquisition (1,3,3) @ 182/23:42:54Z resulted in FL backup
on FGS 1 due to
SSLE on FGS 3. U2,3FM @ 183/23:36:49Z and
182/23:39:34Z showed attitude errors.
May @ 182/23:50:35Z showed errors. Under
investigation.

COMPLETED OPS REQs:
16998-0 Engineering Dump for BCT Critical Engineering Data @ 183/03:16:56z

OPS NOTES EXECUTED:
1115-0 CCC IP CONFIG Connections @ 182/11:20z
1126-0 Bat Cap Test- Adjust CCC5 K1 Level2 Limits 183/0356z

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 13 13
FGS REacq 06 06
FHST Update 14 14
LOSS of LOCK


SIGNIFICANT EVENTS:

Initial commanding for Battery 4 Capacity Test started @ 182/10:27Z with
configuration of
TMDIAGs (OR 16996-1 with attached Battery 4 Capacity Test
script). Battery 4 was connected
to the Diode Bus C and high rate discharge was initiated @ 182/10:43Z,
discharge continued
nominally until approximately 182/23:57Z (during ZOE) when the 15 Volt
termination point
was reached. SA Section 4 was connected to Battery 4 @ 183/01:32Z for
recharging the battery.
Preliminary capacity is 55.8 Ah measured through the 5.1 Ohm
resistor. Plan to configure
the FSW back to a 6-battery system @ approximately 184/17:18Z.

----

Jacques :-)

Editor: www.spacepatches.info

------------------------------------------------------


 




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