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Daily 3392

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Old July 1st 03, 08:19 PM
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DAILY REPORT******* # 3392




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.

FGS 9329

The Masses and Luminosities of Population II Stars

Very little is currently known concerning the mass-luminosity relation
{MLR} of Population II stars. However, with the advent of the
Hipparcos Catalogue, improved distances to many spectroscopic binaries
known to be Pop II systems are now available. After surveying the
literature and making reasonable estimates of the secondary masses, we
find 13 systems whose minimum separation should be larger than the
resolution limit of FGS1. Because of the expected magnitude
differences and separations, it is not possible to resolve the systems
from the ground. We therefore propose FGS observations of the sample.
In combination with the known spectroscopic orbits and Hipparcos
distances, these observations will yield up to 26 precise stellar mass
determinations of metal-poor stars, if all systems are resolved and
the relative orbits are determined. A combination of FGS data and
ground-based observations will lead to component luminosities and
effective temperatures. This program will allow for a significantly
better understanding of the Pop II main sequence, which in turn will
lead to better ages and distances of the galactic globular clusters,
and a Pop II MLR will be constructed for the first time.


Towards a global understanding of accretion physics --, Clues from an UV
spectroscopic survey of cataclysmic variables

Accretion inflows and outflows are fundamental phenomena in a wide
variety of astrophysical environments, such as Young Stellar Objects,
galactic binaries, and AGN. Observationally, cataclysmic variables
{CVs} are particularly well suited for the study of accretion
processes. We propose to carry out a STIS UV spectroscopic snapshot
survey of CVs that fully exploits the diagnostic potential of these
objects for our understanding of accretion physics. This survey will
provide an homogenous database of accretion disc and wind outflow
spectra covering a wide range of mass transfer rates and binary
inclinations. We will analyze these spectra with state-of-the-art
accretion disc model spectra {SYNDISK}, testing our current knowledge
of the accretion disc structure, and, thereby, providing new insight
into the so far not well understood process of viscous dissipation. We
will use our parameterized wind model PYTHON for the analysis of the
radiation driven accretion disc wind spectra, assessing the
fundamental question whether the mass loss rate correlates with the
disc luminosity. In addition, our survey data will identify a number
of systems in which the white dwarf significantly contributes to the
UV flux, permitting an analysis of the impact of mass accretion on the
evolution of these compact stars. This survey will at least double, if
not triple, the number of high-quality accretion disc / wind outflow /
accreting white dwarf spectra, and we waive our proprietary rights to
permit a timely use of this database.


Infrared Photometry of a Statistically Significant Sample of KBOs

While the discovery rate of Kuiper Belt objects is accelerating, the
physical study of this new region of the solar system has been slowed
by a lack of basic astrophysical data. Photometric observations of the
majority of the more than 400 known KBOs and Centaurs are rudimentary
and incomplete, particularly in the infrared. The multicolor
optical-infrared photometry that exists for a small subset of KBOs
often shows significant discrepancies between observations by
different observers. Their intrinsic faintness puts them at the
practical limits of ground-based systems. In July 2001 we began what
will be the largest uniform sample of optical photometry of KBOs with
a WFPC2 SNAPSHOT program that will perform accurate photometry at V,
R, and I on a sample of up to 150 targets. We seek to greatly enhance
the value of this survey by obtaining J and H photometry on the same
sample using NICMOS. Combined optical and infrared broad band
photometry is a far more powerful tool for physical studies than is
either alone. Our sample includes objects that will be observed at
thermal infrared wavelengths by SIRTF and will be used with those data
to derive the first accurate diameters, albedos, and surface
properties for a large sample of KBOs.

STIS 9431

Composition and history of Beta Pictoris- like circumstellar gaseous

The gaseous parts of dust disks surrounding main sequence stars have
been the subject of intense investigations since 1985. The origin of
the gas content was a puzzle around such evolved stars. But the
spectral signatures of Beta Pictoris led to the explanation that the
gas is probably produced by the evaporation of many small bodies {see
Lecavelier et al., 2001, Nature 412, 706}. It is thus believed that
BetaPic-like disks are young planetary systems in the clearing-out
phase. Our previous HST observations confirmed the presence of gas
disks similar to the Beta Pic one. Here we propose new STIS
observations of four stars with known circumstellar gas. Four main
objectives can be achieved with STIS observations: the determination
of the composition of the gas, the investigation of the puzzling high
ionization species, the determination of the CO and CI history and
monitoring of spectral variability. The analysis of these issues will
provide valuable clues to the origin of these gas disks and the
subsequent evolution of young planetary systems. In particular, from
abundance studies it will be possible to show if the gas is produced
by evaporation of bodies like extra-solar comets.

STIS 9447

Characterizing the Atmosphere of an Extrasolar Planet

HD 209458 b is the first extrasolar planet known to transit the disk
of its parent star. Precise measurement of both the photometric
transit curve and the radial velocity orbit has allowed for an
accurate estimation of the mass, radius, average density, and surface
gravity. Numerous theoretical investigations of the planetary
atmospheres have been presented in the literature, but no data capable
of addressing these has yet been published. We propose to use the
method of transmission spectroscopy to constrain greatly models of the
planetary atmosphere. We will use STIS to disperse the stellar flux
over a large number of detector pixels. The photometric signal is
produced by summing the counts over a desired band. For each of twelve
bands spanning the UV to the near-IR, we will obtain sufficient
precision to detect variations in the transit depth greater than 5 X
10^-5. We have already made a detection of the sodium absorption
signature in the planetary atmosphere. With these new data, we will be
able to detect, if present, absorption due to Rayleigh scattering,
water bands, and/or strong alkali metal lines. These observations will
allow us to determine the broad characteristics of the planetary
atmosphere. For example, we will be able to distinguish between models
with a high cloud deck, and those with no clouds but reduced chemical

ACS 9468

ACS Grism Parallel Survey of Emission- line Galaxies at Redshift z pl 7

We propose an ACS grism parallel survey to search for emission-line
galaxies toward 50 random lines of sight over the redshift interval 0
zpl 7. We request ACS parallel observations of duration more than
one orbit at high galactic latitude to identify ~ 300 HAlpha
emission-line galaxies at 0.2pl zpl 0.5, ~ 720 O IILambda3727
emission-line galaxies at 0.3pl zpl 1.68, and pg 1000 Ly-alpha
emission-line galaxies at 3pl zpl 7 with total emission line flux
fpg 2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain
direct images with the F814W and F606W filters and dispersed images
with the WFC/G800L grism at each position. The direct images will
serve to provide a zeroth order model both for wavelength calibration
of the extracted 1D spectra and for determining extraction apertures
of the corresponding dispersed images. The primary scientific
objectives are as follows: {1} We will establish a uniform sample of
HAlpha and O II emission-line galaxies at z1.7 in order to obtain
accurate measurements of co-moving star formation rate density versus
redshift over this redshift range. {2} We will study the spatial and
statistical distribution of star formation rate intensity in
individual galaxies using the spatially resolved emission-line
morphology in the grism images. And {3} we will study high-redshift
universe using Ly-alpha emitting galaxies identified at z pl 7 in the
survey. The data will be available to the community immediately as
they are obtained.

WFPC2 9595


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

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.

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.

ACS/WFC 9684

The Ultraluminous X-Ray Source in Holmberg II

We propose to a program of Chandra and HST observations to test the
recent suggestion that the bright X-ray source in Holmberg II is
surrounded by a photoionization nebula powered by a central object
with a luminosity of order 10^40 erg/s.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

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

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.

STIS 9783

The Ages of Nuclear Star Clusters in Early-type Spiral Galaxies

We propose to obtain STIS G430L spectra of the previously identified
nuclear star cluster in a sample of 16 spiral galaxies of early to
intermediate Hubble type. HST's spatial resolution is required to
separate the nuclear cluster from the underlying galaxy bulge.
Analysis of the spectra with population synthesis methods will reveal
the cluster ages. We will use the age distribution to constrain the
duty cycle of nuclear cluster formation. Comparison of the results to
those for a larger sample of nuclear clusters in late-type, bulgeless
galaxies will allow us to investigate possible differences between the
formation mechanisms of nuclear clusters in early and late Hubble
types. Such differences might be expected because galaxy bulges show a
dichotomy: in late Hubble types, the surface brightness profiles are
best described by an exponential, while they follow a de Vaucouleurs
law in earlier types. Although the reason for this dichotomy is still
unknown, it is plausible that galaxy bulges have different formation
mechanisms at the two ends of the Hubble sequence. We know that {1}
nuclear cluster formation is linked to the funneling of gas towards
the nucleus via gravitational torques from stellar bars, {2} a nuclear
mass concentration can make bars unstable, and {3} unstable bars can
form bulges. Therefore, the age distribution of nuclear star clusters
contains important clues to the evolution of galaxy centers and
promises new insight into the origin of the Hubble sequence.

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


Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be

HSTAR 9061:* FGS 1 search exceeded limits (QF1SRLEX and QF1STOPF) @
176/19:58:36Z and ********************** (QSRCHEXC and QSTOPF) @
176/19:58:40Z.* There was no acquisition or FGS guiding
********************** scheduled, in gyro hold and in an SAA Level 1
(19:51:29Z).* Prior to event, most ********************** recent GS
Acquisition 176/18:36:24Z which was successful with Astrometry on FGS
1. ********************** The term exp occurred @ 176/10:32:35Z.* GS
Acquisition preceding the limits event ********************** was
successful as well. Under investigation.


1115-0* CCC IP CONFIG Connections @ 176/11:06z

************************ SCHEDULED**** SUCCESSFUL*** FAILURE TIMES
FGS GSacq************ 07*********************** 07
FGS REacq************ 09*********************** 09
FHST Update********** 15*********************** 15



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