Status Report

NASA Hubble Space Telescope Daily Report #4697

By SpaceRef Editor
September 17, 2008
Filed under , ,


Continuing to collect World Class Science

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


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.


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

HSTARS: (None)


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


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


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).

SpaceRef staff editor.