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Daily 3822
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3822 PERIOD COVERED: DOY 81 OBSERVATIONS SCHEDULED 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/WFC 10099 The Parallax of Geminga The distances to neutron stars are a fundamental parameter that impacts estimates of radii and luminosities, both of which have important ramifications for neutron star heating and cooling and for the equation of state of nuclear matter. A radius measured to 5% accuracy will provide useful astrophysical constraints on the equation of matter at nuclear densities. This requires an accurate measurement of the distance. Caraveo et al. have reported a distance to the isolated pulsar Geminga based on three WFPC2 images. We have not been able to reproduce that result. We request time with the ACS/WFC over two years to obtain 4 images in order to determine the parallax of Geminga. In addition to the general importance of understanding neutron star radii and luminosities, this will provide specific insights into the history of gamma ray pulsars in general, and of Geminga itself. We have obtained the first two images {cycle 12}; these two cycle 13 images will complete the program. ACS/WFC 10174 Dark-matter halos and evolution of high-z early-type galaxies Gravitational lensing and stellar dynamics provide two complementary methods to determine the mass distribution and evolution of luminous and dark-matter in early-type {E/S0} galaxies. The combined study of stellar dynamics and gravitational lensing allows one to break degeneracies inherent to each method separately, providing a clean probe of the internal structure of massive galaxies. Since most lens galaxies are at redshifts z=0.1-1.0, they also provide the required look-back time to study their structural and stellar-population evolution. We recently analyzed 5 E/S0 lens galaxies between z=0.5 and 1.0, combining exquisite Hubble Space Telescope imaging data with kinematic data from ground-based Keck spectroscopy, placing the first precise constraints on the dark- matter mass fraction and its inner slope beyond the local Universe. To expand the sample to ~30 systems -- required to study potential trends and evolution in the E/S0 mass profiles -- we propose to target the 49 E/S0 lens-galaxy candidates discovered by Bolton et al. {2004} from the Sloan Digital Sky Survey {SDSS}. With the average lens rate being 40% and some systems having a lensing probability close to unity, we expect to discover ~20 strong gravitational lenses from the sample. This will triple the current sample of 9 E/S0 systems, with data in hand. With the sample of 30 systems, we will be able to determine the average slope of the dark-matter and total mass profile of E/S0 galaxies to 10% and 4% accuracy, respectively. If present, we can simultaneously detect 10% evolution in the total mass slope with 95% confidence. This will provide unprecedented constraints on E/S0 galaxies beyond the local Universe and allow a stringent test of their formation scenarios and the standard cosmological model. ACS/WFC/WFPC2 10092 The COSMOS 2-Degree ACS Survey We will undertake a 2 square degree imaging survey {Cosmic Evolution Survey -- COSMOS} with ACS in the I {F814W} band of the VIMOS equatorial field. This wide field survey is essential to understand the interplay between Large Scale Structure {LSS} evolution and the formation of galaxies, dark matter and AGNs and is the one region of parameter space completely unexplored at present by HST. The equatorial field was selected for its accessibility to all ground-based telescopes and low IR background and because it will eventually contain ~100, 000 galaxy spectra from the VLT-VIMOS instrument. The imaging will detect over 2 million objects with I 27 mag {AB, 10 sigma}, over 35, 000 Lyman Break Galaxies {LBGs} and extremely red galaxies out to z ~ 5. COSMOS is the only HST project specifically designed to probe the formation and evolution of structures ranging from galaxies up to Coma-size clusters in the epoch of peak galaxy, AGN, star and cluster formation {z ~0.5 to 3}. The size of the largest structures necessitate the 2 degree field. Our team is committed to the assembly of several public ancillary datasets including the optical spectra, deep XMM and VLA imaging, ground-based optical/IR imaging, UV imaging from GALEX and IR data from SIRTF. Combining the full-spectrum multiwavelength imaging and spectroscopic coverage with ACS sub-kpc resolution, COSMOS will be Hubble's ultimate legacy for understanding the evolution of both the visible and dark universe. ACS/WFC/WFPC2 10424 The White Dwarf Cooling Age and Dynamical History of the Metal-Poor Globular Cluster NGC 6397 We propose to determine the white dwarf cooling age in the nearest metal-poor {[Fe/H]=- 2} globular cluster, NGC 6397. This globular cluster provides the best opportunity to test the white dwarf cooling age in such a metal-poor system and at the same time provide a comparison with the more metal-rich cluster {M4} which we recently successfully observed with HST. Any {or even no} age difference between these clusters will be important in understanding the age-metallicity relation for these systems which reflects the star formation history in the early Galaxy. The absolute age is an important cosmological constraint. We expect to be able to detect age DIFFERENCES between these clusters at the 0.5 Gyr level and absolute ages should be accurate to 1.0 Gyr. In addition, and in contrast with M4, NGC 6397 is highly dynamically evolved, has a collapsed core, and the distribution of its white dwarfs throughout the cluster have almost certainly been modified by dynamical processes. We are using N-body simulations specifically developed for this cluster to understand these modifications and to include their effects in our measurement of the white dwarf luminosity function and cooling age. Among the dynamical questions we expect to answer with this proposal a 1} what was the primordial binary frequency in NGC 6397? 2} can we explain the high central concentration with a population of massive white dwarfs and/or neutron stars? 3} do we see sufficient central binaries to reverse the core collapse of the cluster? FGS 10106 An Astrometric Calibration of the Cepheid Period-Luminosity Relation We propose to measure the parallaxes of 10 Galactic Cepheid variables. When these parallaxes {with 1-sigma precisions of 10% or better} are added to our recent HST FGS parallax determination of delta Cep {Benedict et al 2002}, we anticipate determining the Period-Luminosity relation zero point with a 0.03 mag precision. In addition to permitting the test of assumptions that enter into other Cepheid distance determination techniques, this calibration will reintroduce Galactic Cepheids as a fundamental step in the extragalactic distance scale ladder. A Period-Luminosity relation derived from solar metallicity Cepheids can be applied directly to extragalactic solar metallicity Cepheids, removing the need to bridge with the Large Magellanic Cloud and its associated metallicity complications. NIC1/NIC2/NIC3 8792 NICMOS Post-SAA calibration - CR Persistence Part 3 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. NIC3 10337 The COSMOS 2-Degree ACS Survey NICMOS Parallels The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a companion to program 10092. S/C 4974 TRTTEST The Transcient Response Test is for the periodic performance monitoring of the FGS 2R servo A mechanism. WFPC2 10360 WFPC2 CYCLE 13 INTERNAL MONITOR This calibration proposal is the Cycle 13 routine internal monitor for WFPC2, to be run weekly to monitor the health of the cameras. A variety of internal exposures are obtained in order to provide a monitor of the integrity of the CCD camera electronics in both bays {gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTAR 9746: Full Maneuver Update (U2,3FM) Failure @ 081/14:06:05 (3/22/5) The second of two U2,3FM Full Maneuver Updates scheduled at 081/14:03:20 and 081/14:06:05 respectively, failed with error box results indicating "3FAILED" for mnemonics QEBSTFG0,QEBSTFG1,QEBSTFG2. A single 486 ESB message 901 was observed at 081/14:07:02. Subsequent GSACQ(1,3,3) was successful. No science data was affected. MAP at 081/14:57:31 had 3-axis (RSS) value ~ 14.000 (arcsec). Under investigation. COMPLETED OPS REQs: None OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS Gsacq 6 6 FGS Reacq 9 9 FHST Update 10 9 081/1406z (HSTAR 9746) LOSS of LOCK SIGNIFICANT EVENTS: None |
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