NASA Hubble Space Telescope Daily Report # 4643

HUBBLE SPACE TELESCOPE DAILY REPORT #4643

Continuing to collect World Class Science

PERIOD COVERED: 5am June 30 – 5am July 1, 2008 (DOY 182/0900z-183/0900z)

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.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA Calibration – CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC2 11168

The IMF in the Hidden Galactic Starburst W49A

W49A is one of the most luminous and prolific massive star formation regions in the disk of our Milky Way. Given the presence of several very massive OB clusters as well as an unusually high concentration of many young ultra-compact HII regions (UCHIIR) — all embedded in about 1 million solar masses of molecular gas — it is arguably the best Galactic template for a luminous starburst region. We propose to obtain NICMOS imaging of the central part of W49A, covering a strip from the central, massive OB cluster to the ring of UCHIIRs. Our goals are to resolve and characterize the central star cluster and determine its IMF down to about 1 solar mass. We want to characterize the distribution of intermediate-mass YSOs, and identify the NIR counterparts to the UCHIIRs. The combination of the proposed HST/NICMOS data with our recently obtained Spitzer observations would allow a great step forward in the understanding of massive star and cluster formation.

NIC3 11545

A NICMOS Survey of Newly-Discovered Young Massive Clusters

We are on the cusp of a revolution in massive star research triggered by 2MASS and Spitzer/GLIMPSE, and now is the ideal time to capitalize on these projects by performing the first survey of massive stars in young stellar clusters throughout the Galactic plane. A search of the 2MASS and GLIMPSE surveys has produced over 450 newly-identified massive stellar cluster candidates in the Galactic plane which are hidden from our view at optical wavelengths due to extinction. Here we propose a program of 29 orbits to image the most promising candidate clusters in broad and narrow band filters using HST/NICMOS. We will be complementing these observations with approved Spitzer and Chandra programmes, numerous approved and planned ground-based spectroscopic observations, and state-of-the-art modelling. We expect to substantially increase the numbers of massive stars known in the Galaxy, including main sequence OB stars and post-main sequence stars in the Red Supergiant, Luminous Blue Variable and Wolf-Rayet stages. Ultimately, this programme will address many of the fundamental topics in astrophysics: the slope to the initial mass function (IMF), an upper-limit to the masses of stars, the formation and evolution of the most massive stars, gamma-ray burst (GRB) progenitors, the chemical enrichment of the interstellar medium, and nature of the first stars in the Universe.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#11367 NICMOS Suspended @ 182/0938z

with a status buffer message NICMOS 632, P=201, T=22310, indicating MECH_2_MAX_RETRIES_EXCEEDED. The number of positioning error retries attempted during a Filter Wheel 2 movement exceeded the maximum limit. Per CTMline report the move was to the F110W filter position. Observations affected: NICMOS #38-73 (Proposals #11168, #08795 & #11545).

COMPLETED OPS REQUEST:

18242-1 NICMOS memory dump after suspend @ 182/1311z 18243-0 NICMOS Suspend Recovery @ 182/1820z

COMPLETED OPS NOTES: (NONE)

                                 SCHEDULED      SUCCESSFUL

FGS GSacq                       07                    07
FGS REacq                       07                    07
OBAD with Maneuver              28                    28

SIGNIFICANT EVENTS:

A NICMOS suspend event occured at 182/0938z (30 June/5:38am), see HSTAR #11367 write-up above. NICMOS was recovered and positioned for science operations at 182/1818z (30 June/2:18pm). This put NICMOS back on the science timeline for observation #74 in Proposal #11545 at 182/1836z (30 June/2:36pm).