NASA Hubble Space Telescope Daily Report #3945
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT # 3945
PERIOD COVERED: UT September 14, 2005 (DOY 257)
OBSERVATIONS SCHEDULED
ACS/HRC/WFC 10389
ACS CCDs daily monitor – Cycle 13 – Part 2
This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This program will be for the entire lifetime of ACS.
ACS/HRS 10722
SBC geometric distortions and ACS UV L-flats
The primary goal of this calibration program is to improve the accuracy of the geometric distortion solution for the ACS/SBC imaging modes and to calculate the geometric solution for PR130L for the first time. The secondary goals are to generate an L-flat for PR130L and to provide independent checks for the L-flat and quantum efficiencies of the SBC
ACS/WFC 10505
The Onset of Star Formation in the Universe: Constraints from Nearby Isolated Dwarf Galaxies.
The details of the early star formation histories of tiny dwarf galaxies can shed light on the role in galaxy formation of the reionization which occured at high redshift. Isolated dwarfs are ideal probes since their evolution is not complicated by environmental effects owing to the vicinity of the Milky Way and M31. In addition, dwarf galaxies are the most common type of galaxies, and potentially the building blocks of larger galaxies. Since we can date the oldest stars in them, their study represents a complementary approach to the study of the formation and evolution of galaxies through high-z observations. We propose to use the ACS to obtain a homogeneus dataset of high-quality photometry, down to the old {13 Gyr} main-sequence turnoffs, for a representative sample of 4 isolated Local Group dwarf galaxies. These data are essential to unambiguously determine their early star formation histories, through comparison with synthetic color-magnitude diagrams, and using the constraints provided by their variable stars. Parallel WFPC2 observations of their halos will allow us to reveal the actual nature of their stellar population gradients, providing important aditional constraints on their evolution. The proposed observations are being complemented with ground-based spectroscopy, to obtain metallicity and kinematic information. The observations requested here, which must reach M_I=+3.5 {I=27.5- 28.2} with S/N=10 in crowded systems, can only be achieved with HST using ACS, and won’t be possible with planned ground- or space-based facilities such as JWST. Based on deep WFPC2 observations and ACS image simulations, our team has designed an observational strategy which carefully considers the optimal filter combination, the necessary photometry depth and the effects of stellar crowding.
ACS/WFC 9727
Exploration of the SN Ia Hubble Diagram at z > 1.2
In the spirit of a Treasury proposal, we propose to organize, and deliver to the astronomical community, non-proprietary follow-up observations of ~10 Type Ia supernovae at 1
NIC1/NIC2/NIC3 8793
NICMOS Post-SAA calibration – CR Persistence Part 4
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/NIC1 10419
An in-depth analysis of a prototypical giant H II region: NGC 604
NGC 604 is, together with 30 Doradus, the extragalactic prototype giant H II region. Its stellar content and mass {~200 O+WR stars, ~10**5 M_Sun}, age {~3.5 Myr}, proximity {840 kpc}, and low foreground extinction {E{B-V} <= 0.1} make it an ideal object to study the massive stellar population of a scaled OB association, its interaction with the surrounding medium, and the effects caused by the strong differential extinction. We propose new HST observations which, combined with existent ones, will provide the most thorough multi-wavelength study of NGC 604 from the FUV to the NIR. We will obtain spectral classifications for ~200 stars, measure their spectral energy distributions from 1300 A to 2.2 microns, identify embedded very-young stellar populations hidden inside dust clouds, measure the extinction law and its possible variations as a function of environmental conditions, and analyze the relationship between the hot stars and the surrounding gas. The new data we are proposing is divided into three parts: {a} slitless objective-prism FUV spectroscopy using ACS/SBC, {b} multi-filter {6 broad-band and 2 narrow- band} NUV-optical imaging using ACS/HRC, and {c} HST/NICMOS broadband imaging. Our final goal is to analyze in detail a well-resolved giant H II region in order to understand the properties of similar but unresolved objects located at cosmological distances.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
9949 – GSAcq(2,1,2) results in finelock backup (2,0,2) @ 258/06:34:51z The GSAcq(2,1,2) scheduled at 258/06:34:51 – 06:42:55 Z resulted to finelock backup (2,0,2) using FGS-2, due to scan step limit exceeded on FGS-1 during acquisition walkdown. Prior FHST OBAD1 (with maneuver) scheduled at 258/06:20:53 showed vehicle axis errors: V1=138.48, V2=-271.07, V3=407.48 (arcsec). 3-axis (RSS) value =508.62 arcsec. Prior FHST OBAD2 (with maneuver) scheduled at 258/06:30:21 showed vehicle axis errors: V1=-6.69, V2=-3.15, V3=6.79 (arcsec). 3-axis (RSS) value =10.43 arcsec. Subsequent FHST OBAD (but no maneuver) showed vehicle axis errors: V1=16.03, V2=-3.15, V3=6.79 (arcsec). 3-axis (RSS) value =17.69 arcsec.
9950 – ACS Target Acquisition Failed due to Guide Star Acq Failure ACS target acquisition scheduled at 258/08:17:18 (BD+32D358) failed due to GSacq scheduled at 258/08:10:00 failure to RGA Control The Take Data Flag was down while ACS was executing its Target Acquisition Macro to make a slew request.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SIGNIFICANT EVENTS: (None)
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 10 09 Hstar
# 9950
FGS Reacq 05 05
OBAD with Maneuver 26 26
