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DAILY REPORT # 4155
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4155 PERIOD COVERED: UT July 13, 2006 (DOY 194) OBSERVATIONS SCHEDULED ACS/HRC/WFC 10733 CCD Hot Pixel Annealing Hot pixel annealing will continue to be performed once every 4 weeks. The CCD TECs will be turned off and heaters will be activated to bring the detector temperatures to about +20C. This state will be held for approximately 6 hours, after which the heaters are turned off, the TECs turned on, and the CCDs returned to normal operating condition. To assess the effectiveness of the annealing, a bias and four dark images will be taken before and after the annealing procedure for both WFC and HRC. The HRC darks are taken in parallel with the WFC darks. The charge transfer efficiency {CTE} of the ACS CCD detectors declines as damage due to on-orbit radiation exposure accumulates. This degradation has been closely monitored at regular intervals, because it is likely to determine the useful lifetime of the CCDs. We combine the annealling activity with the charge transfer efficiency monitoring and also merge into the routine dark image collection. To this end, the CTE monitoring exposures have been moved into this proposal . All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} and First Pixel Response {FPR} data will be obtained over a range of signal levels for both the Wide Field Channel {WFC}, and the High Resolution Channel {HRC}. ACS/WFC 10421 Searching for Ancient Mergers in Early Type Host Galaxies of Classical QSOs Recent HST imaging of QSO host galaxies indicates that at least a large fraction of QSOs reside in seemingly undisturbed elliptical hosts. However, our deep Keck spectroscopy of a sample of these host galaxies indicates that many of these objects were involved in a major starburst episode between 0.6 and 1.6 Gyr ago. We propose to obtain very deep ACS WFC observations of the five hosts in this sample that have the most reliable age determinations to search for fine structure indicative of a past merger event and to test the hypothesis that the elliptical hosts are the products of relatively recent merger events rather than old galaxies which formed at high redshifts. By establishing a firm connection between ancient mergers and the aging starbursts in these classical QSOs, we will be able to estimate the fraction of the total QSO population that results directly from mergers accompanied by massive starbursts and to place constraints on the duty cycle for QSO activity. ACS/WFC 10496 Decelerating and Dustfree: Efficient Dark Energy Studies with Supernovae and Clusters We propose a novel HST approach to obtain a dramatically more useful "dust free" Type Ia supernovae {SNe Ia} dataset than available with the previous GOODS searches. Moreover, this approach provides a strikingly more efficient search-and-follow-up that is primarily pre-scheduled. The resulting dark energy measurements do not share the major systematic uncertainty at these redshifts, that of the extinction correction with a prior. By targeting massive galaxy clusters at z 1 we obtain a five-times higher efficiency in detection of Type Ia supernovae in ellipticals, providing a well-understood host galaxy environment. These same deep cluster images then also yield fundamental calibrations required for future weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as well as an entire program of cluster studies. The data will make possible a factor of two improvement on supernova constraints on dark energy time variation, and much larger improvement in systematic uncertainty. They will provide both a cluster dataset and a SN Ia dataset that will be a longstanding scientific resource. ACS/WFC 10503 The Star Formation Histories of Early Type Dwarf Galaxies in Low Density Environments: Clues from the Sculptor Group We seek HST ACS/WFC time to conduct a detailed study of the stellar populations of 5 early-type {dE, dE/dIrr} dwarf galaxies in the nearby {~1.5 to 4 Mpc} Sculptor group. Four of these systems have been recently found to contain modest amounts of HI, and existing ground-based and HST snapshot data point to the potential presence of small populations of young {blue} stars in at least three of these systems. Consequently, they resemble the Local Group 'transition' objects Phoenix and LGS3. The relative number of such transition systems is thus substantially larger in the low density environment of the Scl group than for the Local Group. Detailed stellar populations studies will allow estimation of the star formation histories, via stellar population modelling of the color- magnitude diagrams, of the target dwarfs, which in turn will connect to gas consumption and retention rates. For the two nearer dwarfs we aim to reach below the horizontal branch {a first for any system beyond the Local Group} equivalent to a main sequence turnoff age of ~1 Gyr. The observations of these two systems will also allow detection of RR Lyrae variables and thus direct confirmation of the presence of old populations. For the other three dwarfs will we cover the first 2.5 mags of the red giant branch, equivalent to the main sequence termination for a ~300 Myr population. The results will have implications for theories of galaxy formation and evolution, particularly with regard to the evolutionary relation between low luminosity dEs and dwarf irregulars. NIC1/NIC2/NIC3 8794 NICMOS Post-SAA calibration - CR Persistence Part 5 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. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 10359 - GSacq(1,3,1) not attempted, open loop timer expired @195/0037z GSacq(1,3,1) at 195/00:40:00 was not attempted due to open loop timer expiration. ESB 1806 (T2G Open Loop Timeout) was received at 00:36:38, causing a transition to M2G mode. OBAD prior to GSAcq at 195/00:21:28 showed errors of -31.84, 29.72, -21.42, RSS= 48.57. OBAD after GSACQ at 01:14:36 showed errors of -564.91, -74.65, 205.98, RSS= 605.91. Real Time OBAD was executed at 01:52, errors were -586.19, -80.10, 187.81, RSS= 620.73. REACQ(1,3,1) at 02:14:45 failed due to search radius limit exceeded on FGS 1 at 02:20:24. Observations affected: ACS 199 TO 209, NICMOS 14 TO 30. 10360 - REACQ(1,3,1) failed, FGS1 search radius exceeded @195/0220z REACQ(1,3,1) at 02:14:45 failed due to search radius limit exceeded on FGS 1 at 02:20:24. Real Time OBAD was executed at 01:52 due to failure of previous GSACQ, errors were -586.19, -80.10, 187.81, RSS= 620.73. Observations affected: ACS 199 TO 209, NICMOS 14 TO 30. COMPLETED OPS REQUEST: 17818-0 Battery 3 Capacity Test Script & 5 Battery Pressure Limit COP (thru step 43) @ 194/1537z 17815-0 Continuous Engineering Recording for Battery 3 BCT @194/1559z 17832-0 Real Time OBAD @195/0153z COMPLETED OPS NOTES: (None) SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 6 5 195/0037z (HSTAR#10359) FGS REacq 6 5 195/0220z (HSTAR#10360) OBAD with Maneuver 22 22 SIGNIFICANT EVENTS: Battery 3 Capacity Flash Report #2 The Battery 3 Capacity test recovery period began at approximately 2006/194 12:45 GMT (8:45 am local) with the batteries charging at the K1L4 equivalent. EPS SEs monitored the system for 2 orbits after placing the battery back on-line in H/W and observed nominal system performance. Battery 3 is recovering as expected and battery temperatures have not exceed 1.04 DegC thus far in the recovery. Battery 3 is still scheduled to be placed back on-line in a 6-Battery FSW configuration on 195/14:00 GMT (Friday, July 14th at 10:00 am local). |
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