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Daily 3653
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3653 PERIOD COVERED: DOY 195 OBSERVATIONS SCHEDULED ACS/HRC 10130 Systemic Proper Motions of the Magellanic Clouds from Astrometry with ACS: II. Second Epoch Images We request second epoch observations with ACS of Magellanic Cloud fields centered on the 40 quasars in the LMC and SMC for which we have first epoch Cycle 11 data. The new data will determine the systemic proper motion of the Clouds. An extensive astrometric analysis of the first epoch data shows that follow-up observations with a two year baseline will allow us to measure the proper motion of the clouds to within 0.022 mas/year in each of the two orthogonal directions {assuming that we can image 25 quasars, i.e., with a realistic Snapshot Program completion rate}. The best weighted combination of all previous measurements has a seven times larger error than what we expect. We will determine the proper motion of the clouds with 2% accuracy. When combined with HI data for the Magellanic Stream this will constrain both the mass distribution in the Galactic Halo and theoretical models for the origin of the Magellanic Stream. Previous measurements are too crude for such constraints. Our data will provide by far the most accurate proper motion measurement for any Milky Way satellite. 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/WFC 10248 Current star formation in young, compact clusters in the Small Magellanic Cloud The Small Magellanic Cloud {SMC} offers a deep, resolved stellar population that leverages fundamental parameters {metallicity, dust content} with respect to the Milky Way and to its most studied counterpart, the LMC. Its subsolar metallicity makes it the best analog to the large majority of dwarf irregulars, and gives us the possibility to study star formation and evolution in an environment with the closest {available} resemblance to the early universe. Young, compact clusters are ideal laboratories to investigate how these fundamental differences affect star and cluster formation and evolution. We are therefore, proposing, to use ACS and NICMOS to perform a in depth study of the "resolved" stellar population in the four youngest compact clusters in the SMC. The observations, spanning the UV to the near-IR, will reach the subsolar domain, and will address the following fundamental questions: Does the IMF follow the universal Salpeter's law? Is mass segregation prevalent in the SMC clusters as in LMC clusters? Is on-going star formation present, where and how? What is the role of massive star feedback? The four proposed clusters span an age range from 3-20 Myr, and sample spatially different regions of the SMC. The synergy with NICMOS will permit full characterization of existing pre main sequence stars, if detected. This proposal is part of a coordinated HST and ground-based study of the stellar history and star formation processes in the SMC. ACS/WFC 9751 Accurate Mass Determination of the Ancient White Dwarf ER 8 Through Astrometric Microlensing We propose to determine the mass of the very cool white dwarf ER 8 through astrometric microlensing. We have predicted that ER 8 will pass very close to a 15th-mag background star in January 2006, with an impact parameter of less than 0.05 arcsec. As it passes in front, it will cause a deflection of the background star's image by 8 milliarcsec, an amount easily detectable with HST/FGS. The gravitational deflection angle depends only on the distances and relative positions of the stars, and on the mass of the white dwarf. Since the distances and positions can be determined precisely before the event, the astrometric measurement offers a unique and direct method to measure the mass of the white dwarf to high accuracy {5%}. Unlike all other stellar mass determinations, this technique works for single stars {but only if they are nearby and of sufficient mass}. The mass of ER 8 is of special interest because it is a member of the Galactic halo, and appears to be the oldest known field white dwarf. This object can thus set a lower limit on the age of the Galactic halo, but since white-dwarf cooling rates depend on their masses, the mass is a necessary ingredient in the age determination. As a byproduct, we will obtain an accurate parallax for ER 8, and thus its luminosity and {from its effective temperature} its radius. Such quantities are at present rather poorly known for the coolest white dwarfs, and will provide strong constraints on white-dwarf physics. 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 10149 The Coevolution of Supermassive Black Holes and Galaxies at z~3 The existence of strong correlations between the mass of supermassive black holes and galaxy bulge properties implies that there is an intimate connection between their formation and evolution. How do supermassive black holes grow and how did the correlations come about? Is the growth of supermassive black holes coeval with the growth of the bulge, and is a bulge necessary for AGN activity at high z? We propose to use HST NICMOS to image 9 low-luminosity broad-line AGNs at z~3 in the restframe B-band, identified through the Lyman-break technique. This sample is unique because the AGN luminosities are comparable to Seyfert-like nuclei at z~3, and thus are some of the lowest that have been selected optically. Because of the low total luminosity of the sample, the hosts are likely to be Lyman-break galaxies, which are believed to be the progenitor galaxies of the local Hubble sequence. The goal is to directly detect their host galaxies and to separate the AGN, in order to study the host galaxy morphology and luminosity. From measurement of the bulge luminosity and black hole mass {through available spectra}, we will study the black hole-bulge coevolution out to z~3. We will also compare the luminosity and morphology of these faint AGN hosts with the more luminous and massive host galaxies found in previous HST studies of quasars. NIC2 10176 Coronagraphic Survey for Giant Planets Around Nearby Young Stars A systematic imaging search for extra-solar Jovian planets is now possible thanks to recent progress in identifying "young stars near Earth". For most of the proposed young {~ 30 Myrs} and nearby {~ 60 pc} targets, we can detect a few Jupiter-mass planets as close as a few tens of AUs from the primary stars. This represents the first time that potential analogs of our solar system - that is planetary systems with giant planets having semi-major axes comparable to those of the four giant planets of the Solar System - come within the grasp of existing instrumentation. Our proposed targets have not been observed for planets with the Hubble Space Telescope previously. Considering the very successful earlier NICMOS observations of low mass brown dwarfs and planetary disks among members of the TW Hydrae Association, a fair fraction of our targets should also turn out to posses low mass brown dwarfs, giant planets, or dusty planetary disks because our targets are similar to {or even better than} the TW Hydrae stars in terms of youth and proximity to Earth. HST cycle 13 may be the last chance to find young Solar System analogs in the coming decade. Should HST time be awarded and planetary mass candidates be found, proper motion follow-up of candidate planets will be done with ground-based AOs. STIS 9786 The Next Generation Spectral Library We propose to continue the Cycle 10 snapshot program to produce a Next Generation Spectral Library of 600 stars for use in modeling the integrated light of galaxies and clusters. This program is using the low dispersion UV and optical gratings of STIS. The library will be roughly equally divided among four metallicities, very low {[Fe/H] lt -1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in each bin. Such a library will surpass all extant compilations and have lasting archival value, well into the Next Generation Space Telescope era. Because of the universal utility and community-broad nature of this venture, we waive the entire proprietary period. STIS/CCD 10018 CCD Dark Monitor-Part 2 Monitor the darks for the STIS CCD. STIS/CCD 10020 CCD Bias Monitor - Part 2 Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns. STIS/CCD 10251 SNAPSHOT Survey of SMC Planetary Nebulae A survey of SMC planetary nebulae {PNe} is proposed to study the co-evolution of the nebulae and their central stars, in an environment that is chemically very metal poor. We will obtain STIS imaging and medium-resolution slitless spectroscopy which will yield line fluxes and nebular morphologies in important emission lines, plus magnitudes of the central stars. From these data we will gather a harvest of information: the nebular size, morphology, ionization structure, density, and mass; and the central star temperature, luminosity, and mass. We will explore the correlation found in the Galaxy of nebular bipolarity with large progenitor star mass and with chemical enrichment of the outer envelope during the prior AGB phase. These relationships between PN and central star evolution will be pursued in the SMC with a sample free of distance uncertainties and selection biases, and in a metal-poor chemical environment that stands in sharp contrast to the Galaxy and the LMC. The importance of this program is two-fold: We will determine the late evolutionary paths of the most common stars in a galaxy that, in its chemical content, mimics a young galaxy; and we will produce a sample of extragalactic PN images and spectra that will far exceed in number the galactic PNe already observed with HST, providing an homogeneous database for testing the evolutionary implications of metallicity variations in stellar evolution. STIS/CCD/MA1/MA2 9827 UV extinction by dust in unexplored LMC environments The ensemble of results from studies of the UV extinction in the Milky Way, Magellanic Clouds {MC}, M31 and M33, indicates a complex dependence of the dust properties with environment, where starburst activity and metallicity are relevant factors. Work in the LMC to date, based on IUE data, has several drawbacks: a} only supergiants could be used, b} they all have moderate extinction, c} the IUE S/N is limited, d} the large IUE slit may include light from other sources, such as scattered light from dust or faint companion stars, e} studies are confined to few {extreme} environments. We propose to obtain UV extinction curves more accurate than previous ones {from STIS spectra of main sequence stars with higher reddening}, sampling four environments in the LMC with different levels of star formation activity, including the general field, hitherto unexplored. The results will characterize the properties of dust in different conditions, at the LMC metallicity, which is useful to interpret integrated properties of distant galaxies, as well as GALEX upcoming UV surveys. A complementary study is under way with FUSE in the far-UV range. The combined results will provide insight on the properties of small grains. WFPC2 10067 WFPC2 Cycle 12 Decontaminations and Associated Observations This proposal is for the monthly WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check. 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 COMPLETED OPS REQs: None OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 9 9 FGS REacq 11 11 FHST Update 12 12 LOSS of LOCK SIGNIFICANT EVENTS: None |
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