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)