Status Report

NASA Hubble Space Telescope Daily Report # 3549

By SpaceRef Editor
February 11, 2004
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




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

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.


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.


Dwarf Elliptical Galaxies in Nearby Groups: Stellar Populations and

The M81 group is of the nearest galaxy groups, but its properties are
quite different from the Local Group, providing a different
evolutionary environment for its member galaxies. This team has been
studying M81-group analogs to Local Group dwarf elliptical {dE}
galaxies. We observed two M81-group dEs with WFPC2: the results were
published in Caldwell et al. {1998}. These observations revealed the
upper two magnitudes of the red giant branch, yielding distance via
the luminosity of the red giant branch tip, mean abundance via the
mean giant branch color and first assessment of the star formation
history via the frequency of occurrence of upper-AGB stars. Despite
the different environment, the two M81-group dEs follow the Local
Group {absolute magnitude, mean abundance} relation. But without data
for additional dEs in nearby groups, particularly at higher
luminosities, we can’t definitely say whether this relation is
universal or not. Establishing the answer to this question is vital
because the relation is fundamental to theories of dE formation within
dark matter halos, and the general applicability of these theories
requires demonstration that the relation isn’t strongly influenced by
environment. This proposal requests ACS/WFC observations of five
M81-group dEs to resolve this question.

ACS/WFPC2 9488

Cosmic Shear – with ACS Pure Parallel Observations

The ACS, with greater sensitivity and sky coverage, will extend our
ability to measure the weak gravitational lensing of galaxy images
caused by the large scale distribution of dark matter. We propose to
use the ACS in pure parallel {non- proprietary} mode, following the
guidelines of the ACS Default Pure Parallel Program. Using the HST
Medium Deep Survey WFPC2 database we have measured cosmic shear at
arc-min angular scales. The MDS image parameters, in particular the
galaxy orientations and axis ratios, are such that any residual
corrections due to errors in the PSF or jitter are much smaller than
the measured signal. This situation is in stark contrast with
ground-based observations. We have also developed a statistical
analysis procedure to derive unbiased estimates of cosmic shear from a
large number of fields, each of which has a very small number of
galaxies. We have therefore set the stage for measurements with the
ACS at fainter apparent magnitudes and smaller, 10 arc-second scales
corresponding to larger cosmological distances. We will adapt existing
MDS WFPC2 maximum likelihood galaxy image analysis algorithms to work
with the ACS. The analysis would also yield an online database similar
to that in

FGS 9971

FGS Astrometry of a Star Hosting an Extrasolar Planet: The Mass of
Upsilon Andromedae d

We propose observations with HST/FGS to determine the astrometric
elements {perturbation orbit semimajor axis and inclination} produced
by the outermost extra-solar planet orbiting the F8V star Upsilon
Andromedae. These observations will permit us to determine the actual
mass of the planet by providing the presently unknown sin i factor
intrinsic to the radial velocity method which discovered this object.
An inclination, i = 30degrees, within the range of one very low
precision determination using reanalyzed HIPPARCOS intermediate data
products, would produce the observed radial velocity amplitude, K = 66
ms with a companion mass of ~8 M_Jupiter. Such a mass would induce in
Upsilon Andromedae a perturbation semi-major axis, Alpha = 0arcs0012,
easily within the reach of HST/FGS fringe tracking astrometry. The
proposed observations will yield a planetary mass, rather than, as
previous investigations have done, only suggest a planetary mass

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
0.7<z<1.9, 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.

NIC1/NIC2/NIC3 9997

Photometric Recalibration

This proposal extends the NICMOS photometric calibration for the NCS
era to cover four standard stars: G191B2B, P330E, P177D, and GD71.


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 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.

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 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/CCD 10085

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during
cycle 12.


Connecting the UV and X-ray Warm Absorbers in NGC 5548

In the last Chandra cycle, we were awarded a joint Chandra/HST
proposal to study the warm absorber in NGC 5548 and to obtain a
definitive answer about the connection between the warm absorber and
the UV absorber in this object. We are confident that the deep Chandra
observation {500 ksec} will allow for an unprecedented determination
of the kinematic components in the warm absorber as well as accurate
column density measurements from several line series. However, two new
lines of investigation that appeared after the submission of the
Chandra/HST proposal, suggest that the original modest request for HST
time will not suffice to obtain reliable column density measurements
for the UV absorber. In view of the new evidence, we need a a higher
S/N in the proposed observations to allow for accurate UV column
densities determination. Absorption features in both the UV and warm
absorbers are known to be variable. Therefore, it will be highly
unfortunate if the large investment of Chandra time will not be
accompanied by enough simultaneous HST time to ensure an accurate
measurements of the UV absorber. Without these it will be very
difficult to draw conclusions concerning the relationship between the
two absorbers. We therefore ask for 20 additional STIS E140M Echelle

WFPC2 10070

WFPC2 CYCLE 12 Supplemental Darks Part 2/3

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

WFPC2 10082

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans

WFPC2 10084

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.


Age-dating Star Clusters in M101

M101 represents perhaps our best chance to study the stellar
population of a luminous, late type spiral galaxy, due to both its
proximity and its face-on orientation. For these reasons, 13 orbits of
HST ACS observing time were allocated in Cycle 11 to obtain a 4×4
mosaic image of M101 in BVI . Unfortunately, a degeneracy between age
and reddening exists when only these three bands are available. Hence,
we propose to augment these observations by obtaining WFPC2 U band and
ACS H alpha images. This will enable the accurate determination of
ages for the young clusters, secure identifications of 75-100 old
globular clusters, and allow a quantitative study of the HII region
sizes and structures. Some of the specific questions we will address
are: How do the young clusters form and evolve? What fraction of the
clusters dissolve and on what timescales? Do clusters evolve with a
continuum of properties? Using WFPC2 and ACS in parallel, and making
use of the fact that M101 is in the CVZ, allows us to greatly enhance
the science return of previous HST observations for the cost of only 4


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


1199-0 Adjust ACS Error Count Limit @ 042/09:39:22z

                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                04                        04
FGS REacq                08                        08
FHST Update              12                        12


SpaceRef staff editor.