HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4696

PERIOD COVERED: 5am September 15 - 5am September 16, 2008 (DOY 259/0900z-260/0900z)

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 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.

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.

FGS 11213

Distances to Eclipsing M Dwarf Binaries

We propose HST FGS observations to measure accurate distances of 5

nearby M dwarf eclipsing binary systems, from which model-independent

luminosities can be calculated. These objects have either poor or no

existing parallax measurements. FGS parallax determinations for these

systems, with their existing dynamic masses determined to better than

0.5%, would serve as model-independent anchor points for the low-mass

end of the mass-luminosity diagram.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

HSTARS:

11493 - NCC safed during Restart

           at 259/20:17:02z while executing Ops Request #18286-0 "NCS Restart and

           Cooldown" step #10, NCS PCE On to Circulator On, due to exceeding the

           maximum circulator speed limit. Status Buffer Message EXEC 908 P=200

           T=8371 was received. Per SE request the 8051 memory was dumped.

11494 - NCC safed after restart

           at 259/23:57:14z while executing Ops Request #18289-1. Status Buffer

           Message EXEC 908 P=200 T=48531 was received. The 8051 memory was dumped.

COMPLETED OPS REQUEST:

18286-0  NCS Restart and Cooldown (Execution Failed) @ 259/20:17z

18289-1 NCS Restart and Cooldown (Execution Failed) @ 259/23:57z

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL

FGS GSacq               12                   12                                              

FGS REacq               01                    01                      

OBAD with Maneuver 26                   26                                  

SIGNIFICANT EVENTS:

NCS Restart operations unsuccessful

Upon execution of circulator start up commanding (Ops Request 18286), a

NSCC-1 Status Buffer Message indicated that the circulator was shut down

and the NCC was safed due to exceeding the maximum circulator speed

limit of 1396 rps (Device Table 120). A memory dump is in progress.

Flash Report: DOY 259 - 2nd NCS Restart Attempt.

Following circulatorstart up via Ops Request 18289 and approximately 20

minutes of circulator runtime, a NSSC-1 Status Buffer Message indicated

that the circulator was shut down and the NCC was safed due to exceeding

the maximum circulator current limit of 150mA (Device Table 251). A

memory dump of the start-up is in progress, history buffer of the safing

event is not available.

The CPL start-up heater was commanded back on at 260/00:24:46