NASA Hubble Space Telescope Daily Report # 4512
Note, the next Daily Report won’t appear until 12/26
HUBBLE SPACE TELESCOPE DAILY REPORT # 4512
Continuing to collect World Class Science
PERIOD COVERED: UT December 20, 2007 (DOY 354)
OBSERVATIONS SCHEDULED
ACS/SBC 11145
Probing the Planet Forming Region of T Tauri Stars in Chamaeleon
By studying the inner, planet-forming regions of circumstellar disks around low-mass pre- main sequence stars we can refine theories of giant planet formation and develop timescales for the evolution of disks and their planets. Spitzer infrared observations of T Tauri stars in the Chamaeleon star-forming region have given us an unprecedented look at dust evolution in young objects. However, despite this ground breaking progress in studying the dust in young disks, the gas properties of the inner disk remain essentially unknown. Using ACS on HST, we propose to measure the H_2 emission originating in the innermost disk regions of classical T Tauri stars in different stages of evolution with the objective of revealing the timescales of gas dissipation and its relationship to dust evolution. This proposal is part of a comprehensive effort with approved programs on Spitzer, Gemini, and Magellan that aim to characterize the state of gas and dust in disks where planets may already have formed.
ACS/SBC 11199
A Hard Look at Stellar Disks at the Epoch of Planet Formation
We propose to use HST/ACS/SBC and Chandra/ACIS-S3 to observe the high energy fluxes of 4 stars surrounded by disks in the newly discovered aggregate 25 Ori, the most populous 10 Myr group known within 500 pc. Our observations will cover the 1-25A and 1250-2000A bandpasses, and will complement our optical and Spitzer data for these objects, to provide essential input to physically-consistent models of disk structure and chemistry in the age range around 10 Myr, thought to be a critical period in the planet- forming process. We will be able to determine the Ne/O ratio and determine if the anomalous metal abundances observed in X-ray spectra of young stars are an evolutionary or an environmental effect. Our proposed observations will double the number of 10 Myr old accreting stars with known high energy radiation fields, and will be the first FUV observations of low mass accreting stars in an OB association.
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 i mages. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.
NIC2 11142
Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3
We aim to determine physical properties of IR luminous galaxies at 0.3
targets with spectroscopic redshifts {0.3
NIC3 11107
Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation in the Early Universe
We have used the ultraviolet all-sky imaging survey currently being conducted by the Galaxy Evolution Explorer {GALEX} to identify for the first time a rare population of low- redshift starbursts with properties remarkably similar to high-redshift Lyman Break Galaxies {LBGs}. These “compact UV luminous galaxies” {UVLGs} resemble LBGs in terms of size, SFR, surface brightness, mass, metallicity, kinematics, dust, and color. The UVLG sample offers the unique opportunity of investigating some very important properties of LBGs that have remained virtually inaccessible at high redshift: their morphology and the mechanism that drives their star formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS in order to 1} characterize their morphology and look for signs of interactions and mergers, and 2} probe their star formation histories over a variety of timescales. The images show a striking trend of small-scale mergers turning large amounts of gas into vigorous starbursts {a process referred to as dissipational or “wet” merging}. Here, we propose to complete our sample of 31 LBG analogs using the ACS/SBC F150LP {FUV} and WFPC2 F606W {R} filters in order to create a statistical sample to study the mechanism that triggers star formation in UVLGs and its implications for the nature of LBGs. Specifically, we will 1} study the trend between galaxy merging and SFR in UVLGs, 2} artificially redshift the FUV images to z=1-4 and compare morphologies with those in similarly sized samples of LBGs at the same rest-frame wavelengths in e.g. GOODS, UDF, and COSMOS, 3} determine the presence and morphology of significant stellar mass in “pre-burst” stars, and 4} study their immediate environment. Together with our Spitzer {IRAC+MIPS}, GALEX, SDSS and radio data, the HST observations will form a unique union of data that may for the first time shed light on how the earliest major episodes of star formation in high redshift galaxies came about. This proposal was adapted from an ACS HRC+WFC proposal to meet the new Cycle 16 observing constraints, and can be carried out using the ACS/SBC and WFPC2 without compromising our original science goals.
WFPC2 10915
ACS Nearby Galaxy Survey
Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST’s lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to ~3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to ~1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR~10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for ~100 million stars {comparable to the number in the SDSS survey} and uniform multi- color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high- resolution imaging to the near-infrared.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
11110 – REacq(2,1,1) results in fine lock backup
During LOS REacq(2,1,1) scheduled at 354/16:11:17 resulted in fine lock backup using FGS 2, with QF1STOPF and QSTOP flags set on FGS 1. OBAD 2 showed errors of V1= -8.21, V2= -5.72, V3= -10.63, RSS = 14.60.
11111 – REAcq(2,1,1) results in fine lock backup (2,0,2) using FGS-2
Upon acquisition of signal at 354/21:19:15, the REAcq(2,1,1) scheduled at 354/20:58:10 – 21:06:15 had resulted to fine lock backup (2,0,2) using FGS-2, due to stop flag (QF1STOPF) indication on the primary FGS-1. Pre-acquisition OBAD1 attitude error correction (RSS) not available pending future ETR Dump. OBAD2 had (RSS) value of 10.05 arcseconds. Post-acq OBAD/MAP not scheduled.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 07 07
FGS REacq 08 08
OBAD with Maneuver 30 30
SIGNIFICANT EVENTS:
Ops Request 18165 was successfully executed at 17:09:26 on day 354 (December 20) to uplink the new value for the Universal Kalman Filter (UKF) bias states process noise (Qab).
In M2G intervals after the UKF re-start, the UKF attitude estimate remained within approximately 3 degrees of the commanded vehicle pointing, despite some adverse magnetic field conditions (e.g. SAA passages). During telemetry-available F2G and T2G post-OBAD intervals, the UKF attitude estimate remained within approximately 2 degrees of the known vehicle pointing. No innovations or residuals failures or other anomalous signatures occurred. Real-time monitoring ended at 354/20:15. PCS will continue to trend UKF performance and assess the effects of this change.
