Daily 3760

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3760

PERIOD COVERED: DOY 355

OBSERVATIONS SCHEDULED

ACS/HRC 10199

The Most Massive Galaxies in the Universe: Double Trouble?

We are proposing an HST snapshot survey of 70 objects with velocity
dispersion larger than 350 km/s, selected from the Sloan Digital Sky
Survey. Potentially this sample contains the most massive galaxies in
the Universe. Some of these objects may be superpositions; HST imaging
is the key to determining if they are single and massive or if they
are two objects in projection. The objects which HST imaging shows to
be single objects are interesting because they potentially harbor the
most massive black holes, and because their existence places strong
constraints on galaxy formation models. When combined with ground
based data already in hand, the objects which HST imaging shows are
superpositions provide valuable information about interaction rates of
early- type galaxies as well as their dust content. They also
constrain the allowed parameter space for models of binary
gravitational lenses {such models are currently invoked to explain
discrepancies in the distribution of lensed image flux ratios and
separations}.

ACS/HRC 10377

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 coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC 10391

Wavelength and Flux Calibration of the ACS prisms

The wavelength calibration of the SBC {PR110L and PR130L} and HRC
{PR200L} prisms will be established by observing a planetary nebula in
the LMC and QSOs at carefully selected redshifts. Flux calibrations
will be derived for each prism by observing white dwarf standards.

ACS/HRC/WFC 10367

ACS CCDs daily monitor- cycle 13 - part 1

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS.

ACS/WFC/WFPC2 10265

The Formation History of Andromeda

We propose deep observations of Andromeda's outer disk and giant tidal
stream, to reconstruct their star formation histories. As the nearest
giant galaxy, Andromeda offers the best testing ground for
understanding galaxy formation and evolution. Given the dramatic
increase in sensitivity offered by the ACS, we can now resolve stars
on the old main sequence in the other giant spiral of the Local Group,
and employ the same direct age diagnostics that have been used for
decades in the study of Galactic globular clusters. In Cycle 11, we
successfully observed a field in the Andromeda halo and constructed a
deep color-magnitude diagram reaching well below the oldest main
sequence turnoff. In Cycle 13, we propose to extend these observations
to the outer disk and tidal stream of Andromeda, to constrain their
star formation histories and compare them to that of the halo. The
combined observations from these two programs will offer a dramatic
advance in our understanding of the overall evolution of spiral
galaxies.

ACS/WFC/WFPC2 9392

The Ancient Stars of M32

The question of whether the dwarf elliptical galaxy M32 contains a
population of truly ancient stars has remained unsettled for decades.
We recently used HST/WFPC2 to identify for the first time a population
of RR Lyr stars in this galaxy. Since these stars are known only to be
present in stellar populations older than 8-10 Gyr, we contend that
M32 does possess an old stellar component and certainly cannot be
comprised of only intermediate-age {~ 5 Gyr} stars as has been
frequently suggested in the literature. Our earlier observations were
insufficient to determine even the most basic photometric properties
of these stars. Nor could we use the data to identify independent
evidence of the old population that could help constrain just what
fraction of the galaxy's stars are ancient. We propose new HST/ACS
observations to {a} get periods and luminosities of the previously
observed RR Lyr stars, {b} search for additional RR Lyr stars in a
significantly larger volume of M32, and {c} obtain ultra-deep 2-color
photometry to study the ancient main-sequence turnoff region of that
galaxy directly, {d} look for radial population gradients in M32, both
among the RR Lyr/Horizontal Branch and main- sequence populations, {e}
compare the M31/M32 old populations in terms of metallicity spread,
and {f} use the RR Lyr stars to precisely determine the relative and
possibly the absolute distances of M32 and M31's halo.

FGS 10386

Long Term Monitoring of FGS1r in Position Mode

It is known from our experience with FGS3, and later with FGS1r, that
an FGS on orbit experiences long term evolution, presumably due to
disorption of water from the instrument's graphite epoxy composites.
This manifests principally as a change in the plate scale and
secondarily as a change in the geometric distortions. These effects
are well modeled by adjustments to the rhoA and kA parameters which
are used to transform the star selector servo angles into FGS {x, y}
detector space coordinates. By observing the relative positions of
selected stars in a standard cluster at a fixed telescope pointing and
orientation, the evolution of rhoA and kA can be monitored and
calibrated to preserve the astrometric performance of FGS1r.

FGS 10387

Monitoring FGS1r's Interferometric Response as a Function of Spectral
Color

This proposal obtains reference point source Transfer Functions
{S-Curves} for FGS1r through the F583W filter and the F5ND attenuator
at the center position of the FGS1r FOV for a variety of stars of
different spectral types. These Transfer Functions are needed to
support the analysis of GO science data for the study of close and
wide binary star systems and for determining the angular size and
shape of extended sources. This proposal observes stars that have been
observed in previous cycles to monitor the long term evolution of the
FGS1r S-curves. This proposal also {1} monitors the FGS1r Lateral
Color response {using stars Latcol-A and Latcol-B}, {2} calibrates the
"Pos/Trans" bias of a star's position as determined from Transfer mode
and Position mode observations, and {3} calibrates the shift of a
star's centroid when observed with F5ND relative to that when observed
with F583W.

NIC2 10149

The Coevolution of Supermassive Black Holes and Galaxies at z~3

The existence of strong correlations between the mass of supermassive
black holes and galaxy bulge properties implies that there is an
intimate connection between their formation and evolution. How do
supermassive black holes grow and how did the correlations come about?
Is the growth of supermassive black holes coeval with the growth of
the bulge, and is a bulge necessary for AGN activity at high z? We
propose to use HST NICMOS to image 9 low-luminosity broad-line AGNs at
z~3 in the restframe B- band, identified through the Lyman-break
technique. This sample is unique because the AGN luminosities are
comparable to Seyfert-like nuclei at z~3, and thus are some of the
lowest that have been selected optically. Because of the low total
luminosity of the sample, the hosts are likely to be Lyman-break
galaxies, which are believed to be the progenitor galaxies of the
local Hubble sequence. The goal is to directly detect their host
galaxies and to separate the AGN, in order to study the host galaxy
morphology and luminosity. From measurement of the bulge luminosity
and black hole mass {through available spectra}, we will study the
black hole-bulge coevolution out to z~3. We will also compare the
luminosity and morphology of these faint AGN hosts with the more
luminous and massive host galaxies found in previous HST studies of
quasars.

WFPC2 10132

UV Confirmation of New Quasar Sightlines Suitable for the Study of
Intergalactic Helium

The reionization of intergalactic helium is thought to have occurred
between redshifts of about 3 and 4. The study of HeII Lyman-alpha
absorption towards a half-dozen quasars at 2.7z3.5 demonstrates the
great potential of such probes of the IGM, but the current
critically-small sample limits confidence in resulting cosmological
inferences. The requisite unobscured quasar sightlines to
high-redshift are extremely rare, especially due to severe absorption
in random intervening Lyman-limit systems, but SDSS provides hundreds
of bright, new quasars at such redshifts potentially suitable for HeII
studies. Our cycle 13 SNAP program proposes to verify the UV
detectability of 40 new, bright, z2.9 SDSS quasars, but with special
emphasis on extending helium studies to the highest redshift
sightlines. Our proposed approach has already proven successful, and
additional sightlines will enable follow-up spectral observations to
measure the spectrum and evolution of the ionizing background
radiation, the density of intergalactic baryons, and the epoch of
reionization of the IGM.

WFPC2 10357

Saturn's Inner Satellites at True Opposition

We request one HST orbit to observe Janus, Epimetheus, Mimas, and
Enceladus with WFPC2 exactly at opposition, when the Earth transits
the center of the solar disk seen from Saturn on UT 13/14 January
2005. Data obtained at this unique viewing geometry are essential to
determining physical properties of the moon's surface, related to its
emplacement and evolution, and critical for the interpretation of
photometric data obtained by Cassini at higher phase angles. This
single observation will be the capstone of 9 years of legacy HST WFPC2
observations of the saturnian system {Cycles 6-12, R. French, PI} from
which we have constructed precise, multiwavelength phase curves which
demonstrate how the reflectance of these satellites varies with solar
phase angle from 0.07 to 6.4 degrees. Each satellite exhibits a
dramatic increase in brightness, or "opposition effect", as phase
angles decrease below 1 degree. Since 1998 {Cycle 7} the minimum
observable phase angle at opposition has decreased each year to 0.07
degrees in Cycle 12; however, the absolute minimum observable phase
angle, about 0.02 degrees {limited by the angular size of the Sun
viewed from Saturn}, has not been accessible until Cycle 13. Using the
same set of broadband filters for continuity with our previous
programs, we will place observations made during the Earth transit on
the existing UVBRI phase curves and establish the amplitude of each
satellite's opposition surge. From these observations we will
determine surface properties such as porosity, grain size distribution
and particle opacity using radiative transfer models. While the
Cassini spacecraft will obtain images at larger phase angles, it will
miss entirely the narrow brightness surge near opposition due to
orbital constraints. Because these inner satellites will be either
lost in or contaminated by the glare of the fully open rings, they are
not accessible to ground-based telescopes. The 2005 opposition
presents the only opportunity for HST to observe the saturnian system
during this rare planetary alignment. The next transit of Earth across
the solar disk seen from Saturn occurs in 2020; the next central
transit occurs in 2049.

WFPC2 10359

WFPC2 CYCLE 13 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.

FLIGHT OPERATIONS SUMMARY:

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

HSTAR 9632: GS Acquisition (1,0,1) @ 355/10:36:54Z ended in Gyro
control due to SSLE on FGS 1 @ 355/10:39:44Z. Under investigation.

HSTAR 9633: GS Acquisition (1,2,1) @ 355/20:01:01Z failed to RGA
control due to SRLE on FGS 1 and FGS 2. The two FHST FM Updates @
355/19:55:31Z and 19:58:16Z, prior to the acquisition, both succeeded
and had a very low vehicle error observed. The search radius for the
primary FGA was 55 arcsec. Subsequent FHST Map @ 355/20:09:17Z showed
3-axis (RSS) value ~ 16.00 arcsec. Under investigation.

COMPLETED OPS REQs: None

OPS NOTES EXECUTED: None

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
Gsacq 08 06
355/10:39:44z, 355/20:01:01z
FGS Reacq 08 08
FHST Update 15 15
LOSS of LOCK


SIGNIFICANT EVENTS: None