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Daily 3496



 
 
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Old November 25th 03, 02:24 PM
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Default Daily 3496

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3496

PERIOD COVERED: DOY 328

OBSERVATIONS SCHEDULED

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.

ACS/HRC 10050

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronographic
monitoring is required to assess the changing position of the spots.

ACS/HRC/WFC 10042

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/HRC/WFC 9764

Elliptical galaxies in z~1.5 clusters

Giant elliptical galaxies offer can some of the tightest constraints
on models of galaxy formation. Recent observations have shown
significant inconsistencies between their properties and the
predictions of the currently popular hierarchical clustering models.
Many outstanding questions about the nature and evolution of these
objects can best {or only} be addressed by extending studies of
cluster ellipticals out to z1. Recently we have identified large
overdensities of red galaxies, strongly clustered around powerful
radio sources at z~1.5. We propose to image our two richest fields, of
Abell Class 0-1 richness, using the F814W and F606W filters on the
ACS/WFC. Our goals are to investigate: {1} Galaxy morphologies: we
will determine the bulge fractions of the red cluster galaxies, to
confirm that they are early-types, and measure their characteristic
radii to investigate their evolutionary status. {2} Colour gradients:
we will search for colour gradients indicative of recent star
formation {particularly blue cores}, or inhomogeneities in the
internal colours which might be indicative of recent assembly. {3}
Cluster membership: with two additional colours we will obtain
accurate photometric redshift estimates for all galaxies. Combined
with studies of nearby clusters and of field ellipticals, our results
will place very tight constraints on the formation of the most massive
galaxies.

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.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7z1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial--but poorly observed--redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

NICMOS 8790

NICMOS Post-SAA calibration - CR Persistence Part 1.

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.

STIS/CCD 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 10019

CCD Bias Monitor - Part 1

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/CCD 10022

STIS CCD Hot Pixel Annealing Cycle 12

The effectiveness of the CCD hot pixel annealing process is assessed
by measuring the dark current behavior before and after annealing and
by searching for any window contamination effects. In addition CTE
performance is examined by looking for traps in a low signal level
flat. Follows on from proposal 9612.

STIS/CCD/MA1 10081

Is the exoplanet HD209458b's exosphere in a blowoff state ?

Using HST Lyman alpha observations, we have detected an extended tail
shaped upper atmosphere around the extra-solar planet HD209458b. The
Cycle 10 STIS G140M observations revealed an absorption of 15+/-4% of
the stellar Lyman alpha emission line during the planetary transit in
front of the star {Vidal-Madjar, et al. 2003}. This showed that HI
evaporation is taking place within a highly extended upper atmosphere.
Very recent studies on the evaporation mechanism are now indicating
that instead of ``Jeans escape'' a more probable mechanism is complete
atmospheric ``blowoff'' as suffered by the telluric planets in the
early solar system. This mecanism could be directly tested with HST by
searching for the escape of species slightly heavier than HI. It is
easy to show that neither oxygen nor carbon would be detected with HST
if only ``Jeans escape'' takes place while both species, under
``blowoff'' conditions, should reach the Roche limit of the planet and
escape as hydrogen. If this is the case an absorption during transit
of about 15% should be observed for both. Twelve orbits with the STIS
G140L spectrograph will allow us to detect the presence of these
species during three transits with a better than 5% accuracy, needed
to detect an object of the size of the planetary Roche lobe.
Simultaneously these observations will confirm and give more precision
about the extention of the HI cometary like tail expected to occult
the star well after the end of the visible transit. This proposed
investigation is a unique opportunity to further study hot giant
planets upper atmospheres, reveal the precise evaporation mechanism
and give new constraints on the ``hot Jupiters'' lifetime. This could
explain the lack of planets discovered so far at less than 0.04~AU
from their star. We ask for HST observations under Director
Discretionnary time to have access to the coming transits observable
in the early fall of 2003.

STIS/CCD/MA1 9759

Confirmation of New Candidates for the Study of Intergalactic Helium

The reionization of intergalactic helium is believed to take place
between redshift 3 and 4. The study of HeII Lyman-alpha absorption in
four quasars at 2.7z3.3 demonstrates the great potential of such an
intergalactic-medium {IGM} probe and suggests that the reionization
epoch is at higher redshifts. Clean quasar sightlines may be found
only from massive pre-selection processes in the optical and UV,
because of random, severe absorption by intervening Lyman-limit
systems. The SDSS has discovered approximately 36000 quasars, and we
propose to verify the UV detectability in 70 top candidates for helium
studies extending to even higher redshift. Our proposed approach has
already proven successful, and additional positive confirmations will
allow follow-up observations, with STIS or COS, to pinpoint the epoch
of reionization of the IGM, and the evolution of its properties near
that period.

WFPC2 10068

WFPC2 CYCLE 12 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 10069

WFPC2 CYCLE 12 Supplemental Darks, Part 1/3

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

WFPC2 10072

WFPC2 CYCLE 12 INTERNAL MONITOR

This calibration proposal is the Cycle 12 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a
monitor for possible buildup of contaminants on the CCD windows.

WFPC2 10075

WFPC2 CYCLE 12 Intflat and Viflat Sweeps and Filter Rotation Anomaly
Monitor

Using intflat observations, this WFPC2 proposal is designed to monitor
the pixel-to-pixel flatfield response and provide a linearity check.
The intflat sequences, to be done once during the year, are similar to
those from the Cycle 11 program 9597. The images will provide a backup
database in the event of complete failure of the visflat lamp as well
as allow monitoring of the gain ratios. The sweep is a complete set of
internal flats, cycling through both shutter blades and both gains.
The linearity test consists of a series of intflats in F555W, in each
gain and each shutter. As in Cycle 11, we plan to continue to take
extra visflat, intflat, and earthflat exposures to test the
repeatability of filter wheel motions.

WFPC2 10082

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans

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.

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 08 08
FGS REacq 13 13
FHST Update 12 12
LOSS of LOCK


SIGNIFICANT EVENTS:

Autonomous FGS ITS on-board testing (Proposal 04974) FGS 1 @
329/12:30Z - 12:38Z (Visit 11) and FGS 3 @ 329/12:48Z - 12:56Z (Visit
12).


 




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