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Daily 3683
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3683 PERIOD COVERED: DOY 239 OBSERVATIONS SCHEDULED ACS/HRC 10102 Rings of Uranus: Dynamics, Particle Properties and Shepherding Moons Last year, our Uranian ring and moon observing program {GO-9823} resulted in the discovery of two moons, S/2003 U 1 and S/2003 U 2. We imaged two additional small moons, Ophelia and S/1986 U 10, that had not been seen since the Voyager encounter of 1986. Furthermore, our data show faint arcs and clumps orbiting within the rings, which were not seen by Voyager and are completely unexpected. We employed several "tricks" of the HRC to achieve this remarkable senstivity; specifically, we used the CLEAR filter and oriented the images so that the planet, though vastly overexposed, did not interfere with the ring/moon region of interest to us. This allowed us to detect 25th-magnitude moons circling a 5th-magnitude planet. Now we propose to complete the task by carrying out a comprehensive survey of the system using the same techniques. Our goals are to recover the moons, better discern their orbital elements, and learn more about the dynamics of the ring clumps. In particular, we need to {1} understand the long-term stability of S/2003 U 2, which orbits perilously close to the larger moon Belinda; {2} complete our search for moons, which was only ~ 50% complete last year, and {3} better understand how the clumps and arcs within the ring system might relate to nearby "shepherding" moons, seen or unseen. This program is now a merger of two programs 10275 and 10102. The former is our new program, whereas the latter is the second year of our three-year program to study the light scattering properties of Uranus's rings as they approach their edge-on presentation in 2007. ACS/HRC 10255 A Never Before Explored Phase Space: Resolving Close White Dwarf / Red Dwarf Binaries We propose an ACS Snapshot imaging survey to resolve a well-defined sample of highly probable white dwarf plus red dwarf close binaries. These candidates were selected from a search for white dwarfs with infrared excess from the 2MASS database. They represent unresolved systems {separations less than approximately 2" in the 2MASS images} and are distributed over the whole sky. Our HST+ACS observations will be sensitive to a separation range {1-20 AU} never before probed by any means. The proposed study will be the first empirical test of binary star parameters in the post-AGB phase, and cannot be accomplished from the ground. By resolving as few as 20 of our ~100 targets with HST, we will be able to characterize the distribution of orbital semi-major axes and secondary star masses. ACS/HRC/WFC 10061 CCD Daily Monitor This program consists of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. This programme will be executed once a day for the entire lifetime of ACS. ACS/HRC/WFC 9728 Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae Type Ia supernovae {SNe Ia} provide the only direct evidence for an accelerating universe, an extraordinary result that needs the most rigorous test. The case for cosmic acceleration rests on the observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than they would be in a universe without acceleration. A powerful and straightforward way to assess the reliability of the SN Ia measurement and the conceptual framework of its interpretation is to look for cosmic deceleration at z 1. This would be a clear signature of a mixed dark-matter and dark-energy universe. Systematic errors in the SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia peak luminosity would not show this change of sign. We have obtained a toehold on this putative ``epoch of deceleration'' with SN 1997ff at z = 1.7, and 3 more at z 1 from our Cycle 11 program, all found and followed by HST. However, this is too important a test to rest on just a few objects, anyone of which could be subject to a lensed line-of-sight or misidentification. Here we propose to extend our measurement with observations of twelve SNe Ia in the range 1.0 z 1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be discovered as a byproduct from proposed Treasury and DD programs. These objects will provide a much firmer foundation for a conclusion that touches on important questions of fundamental physics. ACS/WFC 10216 Co-evolution of spheroids and black holes The masses of the giant black holes in galaxies are correlated with the luminosities, masses, and velocity dispersions of their host spheroids. This empirical connection of phenomena on widely different scales {from sub-parsec to kiloparsec} suggests that the evolution of a galaxy and its central black hole are closely linked. We propose to test various unified formation models, by measuring the cosmic evolution of the black hole/spheroid relations, back to z=0.37 {a lookback time of 4 Gyrs}. We will obtain 1-orbit ACS images of a sample of 20 Seyfert 1 galaxies, for which we already have extensive new ground-based measures of the black hole masses and the stellar velocity dispersions. HST resolution is required for accurate measurement of the nonstellar AGN continuum, and the luminosity and effective radius of the bulge of each host galaxy. This will complete the set of observables needed to map the co-evolution of spheroids and black-holes. The proposed sample is the minimum required to make the first measure of the black hole mass/bulge correlation and of the fundamental plane for active galaxies outside the local Universe. WFPC2 10071 WFPC2 CYCLE 12 Supplemental Darks Part 3/3 This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) None ROP: Updated CCS ESB Limit for SESBSLD = 10, Code d0c "Battery SOC below first limit" @ 239/17:37Z (ROP DF-18A). SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 9 9 FGS REacq 11 11 FHST Update 6 6 LOSS of LOCK SIGNIFICANT EVENTS: Completed Battery 3 Capacity Test (OR 17259). Commanding to update the Benchmark SOC and SOC Safing test limits and to restore the nominal 6-battery FSW configuration with TRSWCC and Charge Optimization was completed @ 239/17:46Z. Commanding to restore the Battery Pressure test limits to their nominal values was completed 239/17:54Z (OR 17260). ESTR to BOT and powered off @ 239/09:41Z |
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