Daily Report #4699

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT***** #4699

PERIOD COVERED: 5am September 18 - 5am September 19, 2008 (DOY
262/0900z 263/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC WFPC2 11175

UV Imaging to Determine the Location of Residual Star Formation in
Galaxies Recently Arrived on the Red Sequence

We have identified a sample of low-redshift {z = 0.04 - 0.10} galaxies
that are candidates for recent arrival on the red sequence. They have
red optical colors indicative of old stellar populations, but blue
UV-optical colors that could indicate the presence of a small quantity
of continuing or very recent star formation. However, their spectra
lack the emission lines that characterize star-forming galaxies. We
propose to use ACS/SBC to obtain high-resolution imaging of the UV
flux in these galaxies, in order to determine the spatial distribution
of the last episode of star formation. WFPC2 imaging will provide B,
V, and I photometry to measure the main stellar light distribution of
the galaxy for comparison with the UV imaging, as well as to measure
color gradients and the distribution of interstellar dust. This
detailed morphological information will allow us to investigate the
hypothesis that these galaxies have recently stopped forming stars and
to compare the observed distribution of the last star formation with
predictions for several different mechanisms that may quench star
formation in galaxies.

WFPC2 10884

The Dynamical Structure of Ellipticals in the Coma and Abell 262
Clusters

We propose to obtain images of 13 relatively luminous early type
galaxies in the Coma cluster and Abell 262 for which we have already
collected ground based major and minor axis spectra and images. The
higher resolution HST images will enable us to study the central
regions of these galaxies which is crucial to our dynamical modelling.
The complete data set will allow us to perform a full dynamical
analysis and to derive the dark matter content and distribution, the
stellar orbital structure, and the stellar population properties of
these objects, probing the predictions of galaxy formation models. The
dynamical analysis will be performed using an up-to- date
axi-symmetric orbit superposition code.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey
of a sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so far in
Cycle14 and Cycle15 these systems frequently exhibit strong
gravitational lensing as well as spectacular examples of violent
galaxy interactions. The proposed observations will provide important
constraints on the cluster mass distributions, the physical nature of
galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set
of optically bright, lensed galaxies for further 8-10m spectroscopy.
All of our primary science goals require only the detection and
characterization of high-surface-brightness features and are thus
achievable even at the reduced sensitivity of WFPC2. Because of their
high redshift and thus compact angular scale our target clusters are
less adversely affected by the smaller field of view of WFPC2 than
more nearby systems. Acknowledging the broad community interest in
this sample we waive our data rights for these observations. Due to a
clerical error at STScI our approved Cycle15 SNAP program was barred
from execution for 3 months and only 6 observations have been
performed to date - reinstating this SNAP at Cycle16 priority is of
paramount importance to reach meaningful statistics.

WFPC2 11113

Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution

The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising
and unexpected results. We have found a strong concentration of
binaries among low-inclination Classicals, a possible size cutoff to
binaries among the Centaurs, an apparent preference for nearly equal
mass binaries, and a strong increase in the number of binaries at
small separations. We propose to continue this successful program in
Cycle 16; we expect to discover at least 13 new binary systems,
targeted to subgroups where these discoveries can have the greatest
impact.

WFPC2 11130

AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge
Paradigm, Part II

The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9
solar mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {10^6 solar masses}, if they exist, may
offer important clues to the nature of the seeds of supermassive black
holes. Using the SDSS, our group has successfully uncovered a new
population of AGNs with intermediate-mass black holes that reside in
low-luminosity galaxies. However, very little is known about the
detailed morphologies or structural parameters of the host galaxies
themselves, including the crucial question of whether they have bulges
or not. Surprisingly, the majority of the targets of our Cycle 14
pilot program have structural properties similar to dwarf elliptical
galaxies. The statistics from this initial study, however, are really
too sparse to reach definitive conclusions on this important new class
of black holes. We wish to extend this study to a larger sample, by
using the Snapshot mode to obtain WFPC2 F814W images from a parent
sample of 175 AGNs with intermediate- mass black holes selected from
our final SDSS search. We are particularly keen to determine whether
the hosts contain bulges, and if so, how the fundamental plane
properties of the host depend on the mass of their central black
holes. We will also investigate the environment of this unique class
of AGNs.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

Recent systematic surveys of strong galaxy-galaxy lenses {CLASS,
SLACS, GOODS, etc.} are producing spectacular results for galaxy
masses roughly below a transition mass M~10^13 Mo. The observed lens
properties and their evolution up to z~0.2, consistent with numerical
simulations, can be described by isothermal elliptical potentials. In
contrast, modeling of giant arcs in X-ray luminous clusters {halo
masses M ~10^13 Mo} favors NFW mass profiles, suggesting that dark
matter halos are not significantly affected by baryon cooling. Until
recently, lensing surveys were neither deep nor extended enough to
probe the intermediate mass density regime, which is fundamental for
understanding the assembly of structures. The CFHT Legacy Survey now
covers 125 square degrees, and thus offers a large reservoir of strong
lenses probing a large range of mass densities up to z~1. We have
extracted a list of 150 strong lenses using the most recent CFHTLS
data release via automated procedures. Following our first SNAPSHOT
proposal in cycle 15, we propose to continue the Hubble follow-up
targeting a larger list of 130 lensing candidates. These are
intermediate mass range candidates {between galaxies and clusters}
that are selected in the redshift range of 0.2-1 with no a priori
X-ray selection. The HST resolution is necessary for confirming the
lensing candidates, accurate modeling of the lenses, and probing the
total mass concentration in galaxy groups up to z~1 with the largest
unbiased sample available to date.

WFPC2 11302

WFPC2 CYCLE 16 Standard Darks - Part III

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 11793

WFPC2 Cycle 16 Internal Monitor

This calibration proposal is the Cycle 15 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
(both gain 7 and gain 15 -- to test stability of gains and bias
levels), a test for quantum efficiency in the CCDs, and a monitor for
possible buildup of contaminants on the CCD windows. These also
provide raw data for generating annual super-bias reference files for
the calibration pipeline.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11498 - GSACQ(1,3,1) failed, Search Radius Limit exceeded on FGS 1

GSACQ(1,3,1) at 262/14:08:40 failed to RGA control with Search Radius
Limit exceeded on FGS 1 at 14:14:28.

Observations affected: WFPC 40 to 41, proposal 10884.

11500 - GSacq(1,2,2) failed to RGA hold. @ 262/2019z

The GSacq(1,2,2) scheduled at 262/20:15:42 failed to RGA hold at
20:19:06.

Observations affected: WFPC 57 Proposal ID#11302, WFPC 58-61 Proposal
ID# 11113

COMPLETED OPS REQUEST:

18285-0 - CONTINGENCY Adjust the NCS CPL Reservoir Temperature (8
times)

COMPLETED OPS NOTES: (None)

*********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 13****************** 11
FGS REacq************** 02****************** 02
OBAD with Maneuver **** 30****************** 30

SIGNIFICANT EVENTS: (None)