Daily 3463

HUBBLE SPACE TELESCOPE

DAILY REPORT        # 3463

PERIOD COVERED: DOY 280

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/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/WFC 9756

The Parallax of Geminga

The distances to neutron stars are a fundamental parameter that
impacts estimates of radii and luminosities, both of which have
important ramifications for neutron star heating and cooling and for
the equation of state of nuclear matter. A radius measured to 5%
accuracy will provide useful astrophysical constraints on the equation
of matter at nuclear densities. This requires an accurate measurement
of the distance. Caraveo et al. have reported a distance to the
isolated pulsar Geminga based on three WFPC2 images. We have not been
able to reproduce that result. We request time with the ACS/WFC over
the next two years to obtain 4 images in order to determine the
parallax of Geminga. In addition to the general importance of
understanding neutron star radii and luminosities, this will provide
specific insights into the history of gamma ray pulsars in general,
and of Geminga itself.

ACS/WFC 9891

A snapshot survey of rich stellar clusters in the Large and Small
Magellanic Clouds

Rich stellar clusters are vital to a wide variety of astrophysical
research, from stellar evolution studies to the formation and
evolution of galaxies. In this context, it is important to understand
how rich star clusters form and evolve. The cluster systems in the LMC
and SMC are particularly important in achieving this, because they are
the only systems which contain clusters at all stages of evolution
while being close enough to be studied as fully resolved stellar
populations - although in general this requires the capabilities of
HST. We have recently investigated the structural evolution of LMC and
SMC clusters using archival WFPC2 data, and demonstrated a dramatic
trend in the sizes of these clusters with age. We have shown that this
trend likely represents genuine structural evolution in these
clusters, although it is not clear whether we are observing a
dynamical process or the signature of changing formation conditions.
This result has implications for all astronomical research involving
massive stellar clusters. To develop this work further requires the
extension of our two samples, so that they are statistically
quantifiable. This will allow a number of key questions regarding the
structural evolution trend to be answered. We propose a two-colour
ACS/WFC SNAP survey of rich Magellanic Cloud clusters to achieve this
aim. The unique resolution and sensitivity of ACS/WFC is required for
success, because of the crowded nature of the targets. The SNAP data
will have a large number of additional applications, both to globular
cluster and Magellanic Cloud research.

ACS/WFC/HRC 9771

The local Hubble flow and the density field within 6 Mpc

Great progress has been made recently in accurate distance
measurements of nearby galaxies beyond the Local Group based on the
luminosity of the tip of the red giant branch {TRGB}. Over the last
three years, snapshot surveys with HST have provided us with the TRGB
distances for more than a hundred nearby galaxies obtained with an
accuracy of about 10%. The local velocity field within 5 Mpc exhibits
a significant anisotropy which disagrees with a spherical
Virgo-centric flow. The local Hubble flow is very cold, with 1-D rms
deviations of ~30 km/s. Cosmological simulations with Cold Dark Matter
can only realize such low dispersions with a combination of a low mean
density of matter and a substantial component with negative pressure.
There may be a constraint on the equation of state w=-p/rho. Our
observations will concentrate on 116 galaxies whose expected distances
lie within 4 - 6 Mpc, allowing us to trace a Dark Matter distribution
in the Local Volume with twice the information currently available.
The program is a good one for SNAP mode because the order and rate
that the observations are made are not very important, as long as
there is good completion over several years.

FGS 9879

An Astrometric Calibration of the Cepheid Period-Luminosity Relation

We propose to measure the parallaxes of 10 Galactic Cepheid variables.
There is no other instrument on or off the earth that can consistently
deliver HST FGS level of precision for critical parallaxes. When these
parallaxes {with 1-sigma precisions of 10% or better} are added to our
recent HST FGS parallax determination of delta Cep {Benedict et al
2002}, we anticipate determining the Period-Luminosity relation zero
point with a 0.03 mag precision. In addition to permitting the test of
assumptions that enter into other Cepheid distance determination
techniques, this calibration will reintroduce Galactic Cepheids as a
fundamental step in the extragalactic distance scale ladder. A
Period-Luminosity relation derived from solar metallicity Cepheids can
be applied directly to extragalactic solar metallicity Cepheids,
removing the need to bridge with the Large Magellanic Cloud and its
associated metallicity complications.

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 8792

NICMOS Post-SAA calibration - CR Persistence Part 3

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.

NIC2 9801

Are OH/IR Stars the Youngest post-AGB stars? A NICMOS Imaging Survey

Essentially all well-characterized preplanetary nebulae {PPNe}--
objects in transition between the AGB and planetary nebula
evolutionary phases - are bipolar, whereas the mass-loss envelopes of
AGB stars are strikingly spherical. In order to understand the
processes leading to bipolar mass-ejection, we need to know at what
stage of stellar evolution does bipolarity in the mass-loss first
manifest itself. We have recently hypothesized that most OH/IR stars
{evolved mass- losing stars with OH maser emission} are very young
PPNe. We are conducting a multiwavelength survey program of imaging
and spectroscopic observations of such objects, using a large,
morphologically unbiased sample selected using IRAS 12-to-25 micron
colors. Our ongoing HST/SNAP imaging survey of the optically bright
half of this sample with WFPC2 and ACS is highly successful: 19/32
objects observed are extended with bipolar/multipolar shapes
{remaining objects are unresolved}. Slightly more than 50% of our
sample are optically too faint or undetected but have strong near-IR
counterparts -- we therefore propose a NICMOS SNAPshot imaging survey
of these optically-faint OH/IR stars. These observations are crucial
for determining how and when the bipolar geometry asserts itself. The
results from our NICMOS survey {together with the WFPC2/ACS survey}
will allow us to draw general conclusions about the onset of bipolar
mass-ejection during late stellar evolution. Our complementary program
of interferometric mapping of the OH maser emission in our sources is
yielding kinematic information with spatial resolution comparable to
that in the HST images. The HST/radio data will provide crucial input
for theories of post-AGB stellar evolution. In addition, these data
will also indicate whether the multiple concentric rings, "searchlight
beams'', and truncated equatorial disks recently discovered with HST
in a few PPNe, are common or rare phenomena.

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 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.

STIS/CCD 10000

STIS Pure Parallel Imaging Program: Cycle 12

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

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/MA1 9724

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 are currently carrying out a Cycle 11 STIS UV
spectroscopic snapshot survey of CVs to fully exploit the diagnostic
potential of these objects for our understanding of accretion physics.
While the data obtained so far are of excellent quality, the number of
targets that will be observed in Cycle 11 is too small for a
statistically significant analysis {only 19 objects out of our 149
accepted Cycle 11 snapshot targets have been observed at the time of
writing}. We propose here to extend this survey into Cycle 12,
building a 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 parameterised 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 triple the number
of currently available high-quality accretion disc / wind outflow /
accreting white dwarf spectra, and we waive our proprietary rights to
permit a timely use of this database.

STIS/CCD/MA1 9795

A He-rich O2-3 star in the LMC: Freakish Relic or Paradigm Shifter?

The spectral class O2-3 is a very early, short-lived stage in the
lives of the most massive stars. We recently came across a star in the
LMC whose optical spectrum shows HeII and no HeI, making it a member
of this group. However, there is little or no hydrogen in the spectrum
of this star, suggesting it is a highly evolved object. It is as if we
were looking at the spectrum of a Wolf-Rayet {WR} star {hot and with a
high He/H ratio} but without the characteristic emission lines---what
we would see if a WR had no stellar wind. Nothing about this makes
sense. We can rule out some obvious possibilities {composite spectrum,
foreground white dwarf}. We are requesting here a single orbit so that
we can examine its FUV spectrum and look at the critical stellar wind
diagnostic lines; we will also take advantage of HST's spatial
resolution and obtain narrow-slit spectra in the optical {Halpha and
HeI 4471} that is free of nebular contamination. The star could simply
be an oddity, perhaps the relic of the coalescence of two stars, or
the result of some binary interaction, and of no greater significance.
On the other hand, there are only a few dozen O2-3 stars that have
ever been observed, and maybe this particular one is telling us that
we don't know as much about massive star evolution as we thought. We
really ought to follow this up and determine whether it's simply an
intriguing peculiar star, or something more profoundly interesting.

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 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.)

HSTAR 9169:  GS Acquisition (1,3,3) @ 280/14:37:01Z resulted in FL
backup using FGS 1, after multiple attempts, due to SSLE (QF3SSLEX) on
FGS 3.  FHST Map @ 280/14:50:42Z showed 3-axis (RSS)  error values of
~ 11.00 arcsec.  Under investigation.

HSTAR 9170:  GS Acquisition (1,3,1) @ 280/16:48:43Z (during ZOE)
resulted in FL backup on FGS 3 due to SSLE on FGS 1.  FHST Map @
280/16:31:54Z showed 3-axis (RSS) error value ~ 15.00 arcsec. Under
investigation.

HSTAR 9171:  GS Acquisition (3,1,3) @ 280/19:46:54Z failed to Gyro
control with SSLE on FGS 3.  A 2nd attempt @ 280/10:54:59Z also
failed.  Vehicle attitude was good, FHST Map taken @ 280/19:50Z showed
vehicle axis errors of-1.843, -3.628, and -5.465.  Under
investigation.

COMPLETED OPS REQs:
17052-0 - Continuous Engineering Recording During BCT @ 281/0135z
17050-0 - Battery 3 Capacity Test (thru step 38) @ 281/0046z

OPS NOTES EXECUTED: None

                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                20                       19              280/1946z 
(HSTAR 9171)
FGS REacq                1                         1
FHST Update              7                         7
LOSS of LOCK

SIGNIFICANT EVENTS:

Battery 3 Capacity Test started, as scheduled, at 1st opportunity
280/10:50Z (OR 17050 with attached Battery 3 Capacity Test script).  
SA Section 3 was connected to Diode Bus A @ 280/11:49Z and discharge
continued nominally.  Bus Voltages were observed as low as 26.23 Volts
with adequate SI input Voltage margin.  Capacity measured at the
minimum usable voltage (26.37 Volts) was estimated to be 56.3 A-h as
measured through the 5.1 Ohm discharge resistor (52.3 A-h @ 9 Ampere
rate).  Discharge continued until the battery Voltage decreased to 15
Volts @ approximately 281/00:45Z.  Battery 3 was placed back on charge
@ 281/01:09Z.  To facilitate Battery 3 SOC recovery, the - E SPA was
masked from the software charge control and the OCA was disable.  The
OCA will be re-enabled and the ROC FULROC limit will be restored to
its nominal threshold @ 281/13:40Z.  Battery 3 will be returned to FSW
6-battery system on Day 282.

Due to science data volume during Battery 3 Capacity Test, there were
several gaps in the continuous engineering recording to accommodate
SSR science data playbacks.  The ESTR was used to record engineering
data during the SSR science data playbacks during the following times:  
280/15:05:49Z - 15:49:03Z, 280/17:42:18Z - 18:59:00Z, 280/22:37:31Z -
23:11:00Z, and 281/00:21:01Z - 00:56:00Z. See OR 17052-2 with attached
ESTR Coverage script.