HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4697

PERIOD COVERED: 5am September 16 - 5am September 17, 2008 (DOY 260/0900z-261/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC 11158

HST Imaging of UV Emission in Quiescent Early-type Galaxies

We have constructed a sample of early type galaxies at z~0.1 that have
blue UV-optical colors, yet also show no signs of optical emission, or
extended blue light. We have cross-correlated the SDSS catalog and the
Galaxy Evolution Explorer Medium Imaging Survey to select a sample of
galaxies where this UV emission is strongest. The origin of the UV
rising flux in these galaxies continues to be debated, and the
possibility that some fraction of these galaxies may be experiencing low
levels of star formation cannot be excluded. There is also a possibility
that low level AGN activity {as evidenced by a point source} is
responsible We propose to image the UV emission using the HST/SBC and to
explore the morphology of the UV emission relative to the optical light.

ACS/SBC 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.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic O
Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long term
spectroscopic and high angular resolution observations to determine
their masses and distances. The results will also be important for the
interpretation of the spectra of suspected and newly identified binary
and multiple systems.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST:
18276-0  Patch UIDLE RTCS  @260/1356z
18277-3  Recover WF2 (part1) @260/1405z
18278-2  Recover WF2 (part2) @260/1417z
18285-0  CONTINGENCY Adjust the NCS CPL Reservoir Temperature
        (-11 degC) @260/1439z; (-10 degC) @260/1720; (-9degC) @260/1818z;
        (-8 degC) @260/1911z; (-7degC) @260/2016z; (-6degC) @260/2104z;
        (-5degC) @260/2203z
18280-3  Recover WF2 (part 3) @260/1815z
18281-1  Recover WF2 (part 4) @260/1817z
18291-0  Turn on NCS PCE @260/1910z        

COMPLETED OPS NOTES: (None)

                      SCHEDULED     SUCCESSFUL
FGS GSacq              09                 09                                     
FGS REacq              02                 02                      
OBAD with Maneuver 22                 22                                  

SIGNIFICANT EVENTS:

The WFPC2 recovery is complete. The WFPC2
mechanisms recovery was performed via OR 18280, completed at DOY
260/18:15:34.  CCD Auto-erase was initiated, TEC was powered on, and TEC
set-points were set via OR 18281, completed at 260/18:17:15. The first
WFPC2 science observation will take place on DOY 261/21:00 (Wednesday,

9/17 at 5pm, EDT).