Daily # 4198

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4198

PERIOD COVERED: UT September 13, 2006 (DOY 256)

OBSERVATIONS SCHEDULED

SIGNIFICANT EVENTS: (None)

ACS/HRC/WFC 10758

ACS CCDs daily monitor

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. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The
first half of the program has a different proposal number: 10729.

ACS/WFC 10494

Imaging the mass structure of distant lens galaxies

The surface brightness distribution of extended gravitationally lensed
arcs and Einstein rings contains super-resolved information about the
lensed object, and, more excitingly, about the smooth and clumpy mass
distribution of the lens galaxies. The source and lens information can
non-parametrically be separated, resulting in a direct
"gravitational-mass image" of the inner mass-distribution of
cosmologically-distant galaxies {Koopmans 2005}. With this goal in
mind, we propose deep HST ACS-F555W/F814W and NICMOS-F160W imaging of
15 gravitational-lens systems with spatially resolved lensed sources,
selected from the 17 new lens systems discovered by the Sloan Lens ACS
Survey {Bolton et al. 2004}. Each system has been selected from the
SDSS and confirmed in a time-efficient HST-ACS snapshot program
{cycle-13}; they show highly-magnified arcs or Einstein rings, lensed
by a massive early-type lens galaxy. High- fidelity multi-color HST
images are required {not delivered by the 420-sec snapshot images} to
isolate these lensed images {properly cleaned, dithered and
extinction-corrected} from the lens galaxy surface brightness
distribution, and apply our "gravitational-mass imaging" technique.
The sample of galaxy mass distributions - determined through this
method from the arcs and Einstein ring HST images - will be studied
to: {i} measure the smooth mass distribution of the lens galaxies
{Dark and luminous mass are separated using the HST images and the
stellar M/L values derived from a joint stellar-dynamical analysis of
each system}; {ii} quantify statistically and individually the
incidence of mass-substructure {with or without obvious luminous
counter- parts such as dwarf galaxies}. Since dark-matter substructure
should be considerably more prevalent at higher redshift, both results
provide a direct test of this prediction of the CDM hierarchical
structure-formation model.

ACS/WFC 10880

The host galaxies of QSO2s: AGN feeding and evolution at high
luminosities

Now that the presence of supermassive black holes in the nuclei of
galaxies is a well established fact, other questions related to the
AGN phenomena still have to be answered. Problems of particular
interest are how the AGN gets fed, how the black hole evolves and how
the evolution of the black hole is related to the evolution of the
galaxy bulge. Here we propose to address some of these issues using
ACS/WFC + F775W snapshot images of 73 QSO2s with redshifts in the
range 0.3z0.4. These observations will be combined with similar
archival data of QSO1s and ground based data of Seyfert and normal
galaxies. First, we will intestigate whether interactions are the most
important feeding mechanism in high luminosity AGNs. This will be done
in a quantitative way, comparing the asymmetry indices of QSO2 hosts
with those of lower luminosity AGNs and normal galaxies. Second, we
will do a detailed study of the morphology of the host galaxies of
both QSO types, to determine if they are similar, or if there is an
evolutionary trend from QSO2s to QSO1s. The results from this project
will represent an important step in the understanding of AGN
evolution, and may also introduce a substantial modification to the
Unified Model.

NIC1 10725

Photometric Stability

This NICMOS calibration proposal carries out photometric monitoring
observations during Cycle 14. The format of the program is similar to
that of the Cycle 12 program 9995 and Cycle 13 program 10381, but a
few modifications were made. Provisions had to be made to adopt to 2-
gyro mode {G191B2B was added as extra target to provide target
visibility through most of the year}. Where before 4 or 7 dithers were
made in a filter before we moved to the next filter, now we observe
all filters at one position before moving to the next dither position.
While the previous method was chosen to minimize the effect of
persistence, we now realize that persistence is connected to charge
trapping and by moving through the filter such that the count rate
increases, we reach equilibrium more quickly between charge being
trapped and released. We have also increased exposure times where
possible to reduce the charge trapping non-linearity effects.

NIC1 10889

The Nature of the Halos and Thick Disks of Spiral Galaxies

We propose to resolve the extra-planar stellar populations of the
thick disks and halos of seven nearby, massive, edge-on galaxies using
ACS, NICMOS, and WFPC2 in parallel. These observations will provide
accurate star counts and color-magnitude diagrams 1.5 magnitudes below
the tip of the Red Giant Branch sampled along the two principal axes
and one intermediate axis of each galaxy. We will measure the
metallicity distribution functions and stellar density profiles from
star counts down to very low average surface brightnesses, equivalent
to ~32 V- mag per square arcsec. These observations will provide the
definitive HST study of extra-planar stellar populations of spiral
galaxies. Our targets cover a range in galaxy mass, luminosity, and
morphology and as function of these galaxy properties we will provide:
- The first systematic study of the radial and isophotal shapes of the
diffuse stellar halos of spiral galaxies - The most detailed
comparative study to date of thick disk morphologies and stellar
populations - A comprehensive analysis of halo and thick disk
metallicity distributions as a function of galaxy type and position
within the galaxy. - A sensitive search for tidal streams - The first
opportunity to directly relate globular cluster systems to their field
stellar population We will use these fossil records of the galaxy
assembly process preserved in the old stellar populations to test halo
and thick disk formation models within the hierarchical galaxy
formation scheme. We will test LambdaCDM predictions on sub-galactic
scales, where it is difficult to test using CMB and galaxy redshift
surveys, and where it faces its most serious difficulties.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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 10852

Coronagraphic Polarimetry with NICMOS: Dust grain evolution in T Tauri
stars

The formation of planetary systems is intimately linked to the dust
population in circumstellar disks, thus understanding dust grain
evolution is essential to advancing our understanding of how planets
form. By combining {1} the coronagraphic polarimetry capabilities of
NICMOS, {2} powerful 3-D radiative transfer codes, and {3}
observations of objects known to span the Class II-III stellar
evolutionary phases, we will gain crucial insight into dust grain
growth. By observing objects representative of a known evolutionary
sequence of YSOs, we will be able to investigate how the dust
population evolves in size and distribution during the crucial
transition from a star+disk system to a system containing
planetesimals. When combine with our previous study on dust grain
evolution in the Class I-II phase, the proposed study will help to
establish the fundamental time scales for the depletion of ISM-like
grains: the first step in understanding the transformation from small
submicron sized dust grains, to large millimeter sized grains, and
untimely to planetary bodies.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and
highly non-uniform archive, making comprehensive comparative studies
among galaxies essentially impossible. We propose to secure HST's
lasting impact on the study of nearby galaxies by undertaking a
systematic, complete, and carefully crafted imaging survey of ALL
galaxies in the Local Universe outside the Local Group. The resulting
images will allow unprecedented measurements of: {1} the star
formation history {SFH} of a 100 Mpc^3 volume of the Universe with a
time resolution of Delta[log{t}]=0.25; {2} correlations between
spatially resolved SFHs and environment; {3} the structure and
properties of thick disks and stellar halos; and {4} the color
distributions, sizes, and specific frequencies of globular and disk
clusters as a function of galaxy mass and environment. To reach these
goals, we will use a combination of wide-field tiling and pointed deep
imaging to obtain uniform data on all 72 galaxies within a
volume-limited sample extending to ~3.5 Mpc, with an extension to the
M81 group. For each galaxy, the wide-field imaging will cover out to
~1.5 times the optical radius and will reach photometric depths of at
least 2 magnitudes below the tip of the red giant branch throughout
the limits of the survey volume. One additional deep pointing per
galaxy will reach SNR~10 for red clump stars, sufficient to recover
the ancient SFH from the color-magnitude diagram. This proposal will
produce photometric information for ~100 million stars {comparable to
the number in the SDSS survey} and uniform multi-color images of half
a square degree of sky. The resulting archive will establish the
fundamental optical database for nearby galaxies, in preparation for
the shift of high-resolution imaging to the near-infrared.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10427 - GSAcq (2,1,1) failed due to Search Radius Limit Exceeded on
FGS 2

At AOS 256/22:27:09 GSAcq (2,1,1) scheduled from 256/22:17:20-22:24:24
had failed due to search radius limit exceeded on FGS 2. Received two
486 ESB messages, one 1805 (FHST Moving Target Detected) and one a05
(Exceeded SRL). Pre-acq OBAD #1 data unavailable due to LOS. Pre-acq
OBAD #2 RSS value 21.18 a-s.

At AOS 256/23:07:27 OBAD MAP scheduled at 256/23:01:15 showed the
following values: V1 -723.36, V2 4692.77, V3 -455.02, RSS 4769.95

Upon acquisition of signal at 257/03:23:31, the REacq(2,1,1) scheduled
at 257/03:03:00 - 03:11:04 failed to RGA hold due to search radius
limit exceeded on FGS-2 (QF2SRLEX). Additional ESB "a05" (FGS coarse
track failed, search radius limit exceeded).

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 07 06
FGS REacq 07 06
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)