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Daily 3660
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3660 PERIOD COVERED: DOY 204 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/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/HRC/WFC 9770 Galaxy Evolution During Half the Age of the Universe: ACS imaging of rich galaxy clusters Detailed studies of nearby galaxies {z0.05} have shown that galaxies have very complex histories of formation and evolution involving mergers, bursts of star formation, and morphological changes. Even so, the global properties of the galaxies {radii, luminosities, rotation velocities, velocity dispersions, and absorption line strengths} follow a number of very tight {empirical} scaling relations, e.g. the Tully-Fisher relation and the Fundamental Plane. These relations place constraints on models for galaxy evolution. The results for nearby galaxies rely on high signal-to-noise spectroscopy and multi-color photometry. With the Gemini Telescopes and the Hubble Space Telescope {HST} it is possible to carry out similar detailed studies of galaxies at much larger redshifts, up to z~1.0, equivalent to half the age of the Universe. We have started a project using the scaling relations and aimed at studying the galaxy evolution over the last half of the age of the Universe. The project is based on a large database of spectroscopy and photometry of galaxies in 15 X-ray selected clusters of galaxies with redshifts between 0.15 and 1.0. Spectroscopic observations are being obtained using both Gemini Telescopes; we have observed 6 clusters so far, covering from z=0.18 to z=0.83. We propose to use HST/ACS to image the clusters and determine the morphologies and measure the sizes of the galaxies. At this time we ask for 26 orbits to image four of the clusters in our sample. ACS/WFC 10057 ACS Ramp Filter Calibration We request 3 orbits to observe a well-calibrated region in the Orion Nebula with the primary goal of deriving monochromatic L-flats at specific central wavelengths {lambda_c} for {a} WFC {inner+outer} Halpha {FR716N, FR782N} and [OIII] {FR551N, FR601N} ramp filters. {b} WFC middle ramp filters {FR388N, FR459M, FR505N, FR6546N, FR914M}.{c} HRC middle ramp filters {FR388N, FR459M, FR505N, FR656N, FR914M}. As a secondary goal, we will get an independent check of the wavelength calibration which will be provided by the IDT team from the Cycle 11 program 9671. We request 1.5 CVZ orbits to observe two well-calibrated standard star fields in 47 Tuc with the primary goal of deriving WFC and HRC continuum L-flats for three middle {WFC1-MRAMP} filters: FR656N, FR388N, and FR505N. These filters are selected as they are frequently used to map the Halpha 6563 A, [OII] 3727A, and [OIII] 5007A lines and they include the least {FR388N} and most {FR505N} uniform ramps, based on ground data {ISR ACS 02-01}. These 3 filters should provide a good baseline for testing our approach and gauging the range of non-uniformity in the continuum L-flats. For good spatial sampling, the 2 fields are selected with stellar densities appropriate to WFC and HRC. For good spectral sampling we will step in the central wavelength in steps of 80 A, with 30s exposure at each lambda_c providing good S/N for V=15-20 mag stars. We will use 2K subarrays to reduce the frequency of buffer dumps. ACS/WFC 10158 ACS Observations of the Gravitational Lens B1608+656: Characterizing the Einstein Ring We request time to obtain ACS deep images of the B1608+656 gravitational lens system to fully characterize its enclosing Einstein ring with high signal-to-noise ratio {SNR}. These data will allow us to determine the gravitational potential of the lens, locally, to several percent accuracy and, combined with the three independent time delays, measure H_0 to much better than 10% precision. For this goal, we have developed powerful new lens modeling codes that make use of the full brightness distribution of the Einstein ring in lens systems. The B1608+656 system is ideal for our new code. It has precisely measured time delays, a well-determined stellar velocity dispersion, and an Einstein ring that is not dominated by the lensed nuclear emission of the background source. When combined with high-SNR images of Einstein rings, the new modeling codes provide qualitatively different and much improved analysis of the ring emission than was previously possible. The proposed ACS observations will reach the SNR at which the new modeling code can be fully exploited {SNR=5 per pixel}. Our simulations show that these new data will allow us to reduce the total uncertainties in H_0 derived from the system by at least a factor of two, to the 5-7% level for this system. ACS/WFC/STIS/CCD 10263 SAINTS - Supernova 1987A Intensive Survey SAINTS is a program to observe SN 1987A, the brightest supernova in 383 years, as it transforms into supernova remnant {SNR} 1987A, the youngest supernova remnant. HST is the unique and perfect match in scale and in field for spatially-resolved observations of SN 1987A. Rapid changes are taking place in a violent encounter between the fastest-moving debris and the circumstellar ring. This one-time-only event, leading to suddenly appearing hotspots and new emission that can reveal previously hidden gas, is powered by shocks that can be studied simultaneously with HST and with Chandra to great advantage. Both the optical and X-ray flux from the ring are rising rapidly so prompt observations are needed in Cycle 13. Our previous observations reveal a remarkable reverse shock moving upstream through the expanding debris. The reverse shock provides a powerful tool for dissecting the radial structure of the vanished star. The debris from the explosion itself, still excited by radioactivity, is now well resolved by ACS and seen to be aspherical, providing direct clues to the mechanism of the explosion. Many questions about SN 1987A remain unanswered. SAINTS is a comprehensive attempt to use HST to establish the facts of SN 1987A, help to answer interesting questions, and to observe the birth of SNR 1987A. NIC1 9833 T Dwarf Companions: Searching for the Coldest Brown Dwarfs Faint companions to known stars have historically led to the discovery of new classes of stellar and substellar objects. Because these discoveries are typically limited by the flux ratio of the components in the system, the intrinsically faintest companions are most effectively identified around the intrinsically faintest primaries. We propose to use NICMOS to image a sample of 22 of the coolest known {T-type} brown dwarfs in the Solar Neighborhood in order to search for fainter and cooler brown dwarf companions. The high spatial resolution of the NIC 1 detector enables us to distinguish binary systems with apparent separations greater than 0"08, or physical separations greater than 1.2 AU at the nominal distances of the objects in our sample. Furthermore, the substantial sensitivity of NICMOS imaging allows us to probe companion masses of 5-50 Jupiter masses and companion effective temperatures of 250-1300 K in a maximally efficient manner. Based on work to date, we expect that roughly 20% of the objects in our sample will be binary, and that one or two of these will likely harbor a significantly fainter secondary. Hence, we expect to find a companion cooler than any currently known brown dwarf, a potential prototype for the next spectral class. In addition, our investigation will add substantially to the sample of known binary brown dwarfs, allowing improved statistical analyses of the binary fraction, separation distribution, and mass ratio distribution of these systems, key quantities for probing brown dwarf formation. We will also identify optimal substellar systems for astrometric mass measurements, a critical check for theoretical models of brown dwarfs and extrasolar planets. 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 9875 The Fundamental Plane of Massive Gas-Rich Mergers We propose deep NICMOS H-band imaging of a carefully selected sample of 33 luminous, late-stage galactic mergers. This program is part of a comprehensive investigation of the most luminous mergers in the nearby universe, the ultraluminous infrared galaxies {ULIGs}. The high-resolution HST images will complement an extensive set of ground-based data that include long-slit NIR spectra from a recently approved Large VLT Programme. This unique dataset will allow us to derive with unprecedented precision structural -and- kinematic parameters for a large unbiased sample of objects spanning the entire ULIG luminosity function. These data will refine the fundamental plane of massive gas-rich mergers and enable us to answer the following questions: {1} Do ultraluminous mergers form elliptical galaxies, and in particular, giant ellipticals? {2} Do ULIGs evolve into optically bright QSOs? The results from this detailed study of massive mergers in the local universe will be relevant to understanding galaxy formation and evolution at earlier epochs, and in particular, the dusty sub-mm population that accounts for more than half of the star formation at z 1. NIC3 9846 The Origins of Sub-stellar Masses: Searching for the End of the IMF Is there a preferred scale that defines the end of the IMF? We propose to test this hypothesis by conducting a deep spectroscopic survey of extremely low mass objects in the embedded young cluster associated with NGC1333. At a distance of only 300pc, this cluster is one of the nearest examples of a dense young cluster. We will be able to obtain R=200 spectra and photometry for 40-60 cluster members with masses between 5-40 Jupiter masses at an age of 1 Myr observed through A{v}10 mag. This will enable us to estimate temperatures and luminosities for all sources detected in the survey. We will compare their positions in an H-R diagram to PMS evolutionary tracks in order to estimate their ages and masses. For a solar metallicity cloud at a temperature of 10 K, the minimum mass for fragmentation is thought to be 10 Jupiter masses. A statistically significant sample of objects detected below this limit would challenge the role of hierarchical fragmentation in limiting substellar masses. The proximity of this cluster combined with the unique sensitivity, wavelength coverage, and multi-object spectroscopic capability of NICMOS on HST make this experiment possible. 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. 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.) HSTAR 9488 - GSACQ(1,2,1) resulted in fine lock backup GSACQ(1,0,1). The Gsacq(1,2,1) scheduled at 204/22:51:03 - 22:58:24 resulted in finelock backup (1,0,1) due to search radius limit exceeded on FGS-2. Prior FM Updates at 204/22:44:52, 204/22:47:37 both succeeded with no trouble. There was no map scheduled because the next acquisition was scheduled within the hour. Possible Observations affected: STIS 42, 43. Under investigation. COMPLETED OPS REQs: None OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 12 12 FGS REacq 06 06 FHST Update 15 15 LOSS of LOCK SIGNIFICANT EVENTS: None |
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