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Daily 3674
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3674 PERIOD COVERED: DOYs 226-228 OBSERVATIONS SCHEDULED NIC1/NIC2/NIC3 9993 Cycle 12 NICMOS dark current, shading profile, and read noise monitoring program The purpose of this proposal is to monitor the dark current, read noise, and shading profile for all three NICMOS detectors throughout the duration of Cycle 12. This proposal is an essentially unchanged continuation of PID 9636 which cover the duration of Cycle 11. WFPC2 9964 Dynamical Masses of White Dwarfs from Resolved Sirius-Like Binaries In Cycle 8 we initiated a WFPC2 snapshot survey for resolved, ``Sirius-like'' systems containing hot white-dwarf companions of cooler main-sequence stars. Out of 17 systems observed to date, 8 have been resolved with WFPC2 by using UV filters. Two of the resolved systems---56 Persei and Zeta Cygni---have predicted or known orbital periods short enough that dynamical masses can be determined for the white dwarfs within reasonable times. These would thus add to the extremely small number of white dwarfs presently having accurately and directly measured masses. We propose to image them annually in the UV with WFPC2. In addition, we will observe Zeta Cyg with FGS in order to measure the absolute motion of the optical component, needed for the mass solution. We also propose to observe Sirius itself with WFPC2 over the next 3 Cycles. The resulting astrometric data will not only greatly improve the precision of the binary orbit and the dynamical mass measurements for both the main-sequence and white-dwarf components, but will also test definitively for the claimed presence of a third body in this famous system. ACS/WFC/WFPC2 9837 Stellar Populations in the Outskirts of M33: A Unique Probe of Disk Galaxy Formation The fossil record of galaxy formation and evolution is imprinted on the structure and composition of galactic stellar populations. We have recently completed an extensive ground-based imaging survey of the low mass Local Group spiral, M33. Our analysis of the global structure of M33 suggests it is a 'pure disk' galaxy, with no discernible stellar halo. Furthermore, the disk surface brightness declines very abruptly beyond ~5 scalelengths. We propose here to obtain deep ACS imagery of two fields in the far outer disk of M33, located at 4.5 and 6 exponential scalelengths. Deep colour-magnitude diagrams reaching main sequence turn-offs of ~8 Gyr {corresponding to star formation episodes since z 1} will be constructed and used for quantitative modelling of the star formation history. State-of-the-art cosmological simulations of galaxy formation predict stars in the outer regions of galactic disks should be predominantly young-to-intermediate age. The data we propose to obtain will directly test this idea, and provide a much-needed observational constraint on the epoch at which disk galaxies were assembled. The proposed observations will provide an excellent complement to an ongoing Cycle 11 program to study the outer disk of the more massive system, M31. 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 9727 Exploration of the SN Ia Hubble Diagram at z 1.2 In the spirit of a Treasury proposal, we propose to organize, and deliver to the astronomical community, non-proprietary follow-up observations of ~10 Type Ia supernovae at 1z1.7 that are expected to be discovered in a Cycle 12 Treasury proposal. Together with the currently available sample, this would provide a Hubble diagram with over 20 SNe Ia in this redshift range, where it is possible to test the current cosmological model in the epoch of deceleration: If z ~ 0.5 SNe Ia are fainter due to evolution rather than an accelerating expansion, they should continue to get fainter at even higher redshifts. This size sample will show trends and outliers, and permit a more rigorous treatment of the asymmetric amplification distribution from gravitational lensing. This is a key redshift range for the studies of dark energy that will be done with future surveys {and future instruments now being designed}; this dataset will lay the ground-work for these studies by establishing the simple properties of the supernovae in this redshift range, including magnitudes, colors, and timescales. If considered more appropriate, this proposal could be treated as a part of a Treasury or Director's Discretionary program, since the data would be available to everybody immediately, and we would welcome others who would want to work with us on it. 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. ACS/WFC/WFPC2 10273 Accurately Mapping M31's Microlensing Population We propose to augment an existing microlensing survey of M31 with source identifications provided by a modest amount of ACS {and WFPC2 parallel} observations to yield an accurate measurement of the masses responsible for microlensing in M31, and presumably much of its dark matter. The main benefit of these data is the determination of the physical {or "Einstein"} timescale of each microlensing event, rather than an effective {"FWHM"} timescale, allowing masses to be determined more than twice as accurately as without HST data. The Einstein timescale is the ratio of the lensing cross-sectional radius and relative velocities. Velocities are known from kinematics, and the cross-section is directly proportional to the {unknown} lensing mass. We cannot easily measure these quantities without knowing the amplification, hence the baseline magnitude, which requires the resolution of HST to find the source star. This makes a crucial difference because M31 lens mass determinations can be more accurate than those towards the Magellanic Clouds through our Galaxy's halo {for the same number of microlensing events} due to the better constrained geometry in the M31 microlensing situation. Furthermore, our larger survey, just completed, should yield at least 100 M31 microlensing events, more than any Magellanic survey. A small amount of ACS+WFPC2 imaging will deliver the potential of this large database {about 350 nights}. For the whole survey {and a delta-function mass distribution} the mass error should approach only about 15%, or about 6% error in slope for a power-law distribution. These results will better allow us to pinpoint the lens halo fraction, and the shape of the halo lens spatial distribution, and allow generalization/comparison of the nature of halo dark matter in spiral galaxies. In addition, we will be able to establish the baseline magnitude for about 50, 000 variable stars, as well as measure an unprecedentedly detailed color-magnitude diagram and luminosity function over much of M31. ACS/HRC 10272 A Snapshot Survey of the Sites of Recent, Nearby Supernovae During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a snapshot imaging survey of the sites of some of these nearby objects, to obtain late-time photometry that {through the shape of the light and color curves} will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environment of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-color and color-magnitude diagrams of stars in these SN sites, to determine their progenitor masses and constraints on the reddening. Recovery of the SNe in the new HST images will also allow us to actually pinpoint their progenitor stars in cases where pre-explosion images exist in the HST archive. Use of ACS rather than WFPC2 will make our snapshot survey even more valuable than our Cycle 9 survey. This Proposal is complementary to our Cycle 13 archival proposal, in which we outline a plan for using existing HST images to glean information about SN environments. 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/WFPC2 10227 Globular Cluster Systems of Giant, Post-Starburst Shell Ellipticals Mergers seem to have played a major role in determining the shapes and dynamics of elliptical galaxies. A few galactic mergers still occur and offer valuable clues to past evolutionary processes. Young globular clusters formed during mergers hold strong promise for age-dating such events, besides helping shed light on the cluster-formation process itself. With young globulars in ongoing mergers and ~0.5 Gyr old remnants now well studied {NGC 4038/39, 3256, 7252, and 3921}, we propose to observe 4 bona fide ellipticals featuring ripples, tidal tails as well as post-starburst spectra {E+A galaxies: strong Balmer absorption}, which are obvious candidates for having undergone a dissipative merger 1-4 Gyr ago. If the globulars formed during mergers are formed with a normal IMF, they should still be around in large numbers in intermediate-age systems. If that is indeed the case, it would constitute strong evidence in favor of the scenario in which metal-rich globulars in 'normal' ellipticals are formed in merging events. We plan to use these ACS observations to {1} measure high-accuracy {g-I error of 0.1 mag} colors for clusters as faint as the peak of the luminosity function {LF} of old globulars, {2} use these colors to separate first- and second-generation clusters, and {3} determine the LFs of the two kinds of clusters down to 1.5 mag past the LF peak for old globulars. Deep dithered g&I-band images form a crucial part of our observing strategy. When combined with previous HST studies of globulars in mergers, this study will yield about a dozen globular cluster systems with age estimates, enough to make meaningful statements about the influence of mergers in creating "red'', metal-rich globulars in giant E's and the evolution of the specific frequency of globular clusters during galactic mergers. NIC/NIC3 10226 The NICMOS Grism Parallel Survey We propose to continue managing the NICMOS pure parallel program. Based on our experience, we are well prepared to make optimal use of the parallel opportunities. The improved sensitivity and efficiency of our observations will substantially increase the number of line-emitting galaxies detected. As our previous work has demonstrated, the most frequently detected line is Halpha at 0.7z1.9, which provides an excellent measure of current star formation rate. We will also detect star-forming and active galaxies in other redshift ranges using other emission lines. The grism observations will produce by far the best available Halpha luminosity functions over the crucial--but poorly observed--redshift range where galaxies appear to have assembled most of their stellar mass. This key process of galaxy evolution needs to be studied with IR data; we found that observations at shorter wavelengths appear to have missed a large fraction of the star-formation in galaxies, due to dust reddening. We will also obtain deep F110W and F160W images, to examine the space densities and morphologies of faint red galaxies. In addition to carrying out the public parallels, we will make the fully reduced and calibrated images and spectra available on-line, with some ground-based data for the deepest parallel fields included. FGS 10202 Resolving OB Binaries in the Carina Nebula, Resuming the Survey In March 2002 we carried out a small, high-angular resolution survey of some of the brightest OB stars in the Carina Nebula with FGS1r in an attempt to resolve binary systems which had thus far evaded detection by other techniques. Of 23 stars observed, 5 new OB binaries were discovered with component separations ranging from 0.015" to0.325". This yield over the spatial domain of FGS1r's angular resolution, coupled with published statistics of the incidence of OB stars in short-period spectroscopic, and long-period visual binaries suggests that the fraction of binarity or multiplicity among OB stars is near unity. Our unexpected resolution of the prototype O2 If* star HD 93129A as a 55 milli-arcsecond double is a case in point that great care must be exercised when one attempts to establish the IMF and upper-mass cuttoff at the high-mass end of the HR diagram. We propose to resume the survey to observe a larger, statistically meaningful sample of OB stars to establish a firm assessment of multiplicity at the high-mass end of the IMF in these clusters. We will also investigate the single-star/binary-star status of several astrophysically important, individual stars in order to enable a better understanding of the evolution of high-mass stars. ACS/HRC 10199 The Most Massive Galaxies in the Universe: Double Trouble? We are proposing an HST snapshot survey of 70 objects with velocity dispersion larger than 350 km/s, selected from the Sloan Digital Sky Survey. Potentially this sample contains the most massive galaxies in the Universe. Some of these objects may be superpositions; HST imaging is the key to determining if they are single and massive or if they are two objects in projection. The objects which HST imaging shows to be single objects are interesting because they potentially harbor the most massive black holes, and because their existence places strong constraints on galaxy formation models. When combined with ground based data already in hand, the objects which HST imaging shows are superpositions provide valuable information about interaction rates of early-type galaxies as well as their dust content. They also constrain the allowed parameter space for models of binary gravitational lenses {such models are currently invoked to explain discrepancies in the distribution of lensed image flux ratios and separations}. ACS/HRC 10198 Probing the Dynamics of the Galactic Bar through the Kinematics of Microlensed Stars The observed optical depths to microlensing of stars in the Galactic bulge are difficult to reconcile with our present understanding of Galactic dynamics. The main source of uncertainty in those comparisons is now shifting from microlensing measurements to the dynamical models of the Galactic bar. We propose to constrain the Galactic bar models with proper motion observations of Bulge stars that underwent microlensing by determining both the kinematic identity of the microlensed sources and the importance of streaming motions. The lensed stars are typically farther than randomly selected stars. Therefore, our proper motion determinations for 36 targeted MACHO events will provide valuable constraints on the dynamics of bulge stars as a function of distance. The first epoch data for our proposed events is already available in the HST archive so the project can be completed within a single HST cycle. The exceptional spatial resolution of HST is essential for completion of the project. Constraints on the total mass in the bulge will ultimately lead to the determination of the amount of dark matter in inner Galaxy. FGS 10197 The Astrophysical Parameters of Very Metal-Poor Halo Binaries Little is currently known concerning the mass-luminosity relation {MLR} of Population II stars. In Cycle 10, we began an initial study with FGS1 to resolve a sample of known spectroscopic binaries preselected as high-velocity and/or low metallicity objects. This has resulted in significant new information about the astrophysical parameters of metal-poor stars, but was limited mainly to intermediate metallicities, not to true Population II stars. A new sample of metal-poor spectroscopic binaries identified by Latham and his collaborators {e.g. Latham et al 2002} contains three new very metal-poor objects resolvable with FGS. We propose to observe these binaries and obtain additional observations of two very important resolved targets from our initial sample. As with that program, we will couple the already-known spectroscopic orbits with astrometric information which only FGS can deliver at present. To ensure that the most will be gained from these data, we also request observations of three metal-poor single stars to be used as calibration objects. In combination with results from our previous program, these observations can be expected to resolve the question of the location of the Population II main sequence and give valuable insight into the accuracy of isochrone fitting for determination of globular clusters ages. Due to the combination of target magnitudes and expected separations, no object in this sample can be resolved without the unique capabilities of FGS. NIC2 10177 Solar Systems In Formation: A NICMOS Coronagraphic Survey of Protoplanetary and Debris Disks Until recently, despite decades of concerted effort applied to understanding the formation processes that gave birth to our solar system, the detailed morphology of circumstellar material that must eventually form planets has been virtually impossible to discern. The advent of high contrast, coronagraphic imaging as implemented with the instruments aboard HST has dramatically enhanced our understanding of natal planetary system formation. Even so, only a handful of evolved disks {~ 1 Myr and older} have been imaged and spatially resolved in light scattered from their constituent grains. To elucidate the physical processes and properties in potentially planet-forming circumstellar disks, and to understand the nature and evolution of their grains, a larger spatially resolved and photometrically reliable sample of such systems must be observed. Thus, we propose a highly sensitive circumstellar disk imaging survey of a well-defined and carefully selected sample of YSOs {1-10 Myr T Tau and HAeBe stars} and { app 10 Myr} main sequence stars, to probe the posited epoch of planetary system formation, and to provide this critically needed imagery. Our resolved images will shed light on the spatial distributions of the dust in these thermally emissive disks. In combination with their long wavelength SEDs the physical properties of the grains will be discerned, or constrained by our photometrically accurate surface brightness sensitivity limits for faint disks which elude detection. Our sample builds on the success of the exploratory GTO 7233 program, using two-roll per orbit PSF-subtracted NICMOS coronagraphy to provide the highest detection sensitivity to the smallest disks around bright stars which can be imaged with HST. Our sample will discriminate between proposed evolutionary scenarios while providing a legacy of cataloged morphologies for interpreting mid- and far-IR SEDs that the recently launched Spitzer Space Telescope will deliver. NIC2 10173 Infrared Snapshots of 3CR Radio Galaxies Radio galaxies are an important class of extragalactic objects: they are one of the most energetic astrophysical phenomena and they provide an exceptional probe of the evolving Universe, lying typically in high density regions but well-represented across a wide redshift range. In earlier Cycles we carried out extensive HST observations of the 3CR sources in order to acquire a complete and quantitative inventory of the structure, contents and evolution of these important objects. Amongst the results, we discovered new optical jets, dust lanes, face-on disks with optical jets, and revealed point-like nuclei whose properties support FR-I/BL Lac unified schemes. Here, we propose to obtain NICMOS infrared images of 3CR sources with z0.3 as a major enhancement to an already superb dataset. We aim to deshroud dusty galaxies, study the underlying host galaxy free from the distorting effects of dust, locate hidden regions of star formation and establish the physical characteristics of the dust itself. We will measure frequency and spectral energy distributions of point-like nuclei, expected to be stronger and more prevalent in the IR, seek spectral turnovers in known synchrotron jets and find new jets. We will strongly test unified AGN schemes and merge these data with existing X-ray to radio observations. The resulting database will be an incredibly valuable resource to the astronomical community for years to come. ACS/WFC 10146 Solving the problem of the White Dwarf Cooling Sequence End in M4: an efficent approach The end of the white dwarf {WD} cooling sequence {WDCS} has never been observed, despite the importance that it has in providing an age estimate of old stellar systems, independent from the standard method of the main sequence turn off. The best targets for this investigation are the closest stellar clusters, and, among them, globular clusters are the most interesting ones. Being the oldest stellar aggregates, they allow to probe the advanced WD cooling phases, and the independent age estimate coming from the end of their WDCS has an important cosmological impact. M4 is the best target for this investigation. Despite huge observational efforts, we still miss the end of its WDCS. The ACS camera offers a unique opportunity to identify it. Coupled with already existing observations, we can finally reach it with only 10 HST orbits. The data we are requesting here, will also be used to complete other two programs of great astrophysical impact: the observational detection of the main sequence hydrogen burning limit, and the measurement of the geometrical distance of M4. ACS/HRC 10137 Cluster Archeology: The Origin of Ultra-compact Dwarf Galaxies Ultra-compact dwarf {UCD} galaxies are a new type of galaxy we have discovered in the central regions of the Fornax and Virgo galaxy clusters. Our most recent observations in the Fornax Cluster show that UCDs outnumber normal galaxies in the center of that cluster. Here we propose snapshot imaging of UCDs in the Fornax and Virgo clusters to test theories of how these fascinating objects formed. In particular we wish to image Virgo cluster UCDs for which we have ground-based Keck spectroscopy to test predictions that they formed more recently than the Fornax UCDs. 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. FGS 10110 Parallaxes of Extreme Halo Subgiants: Calibrating Globular Cluster Distances and the Ages of the Oldest Stars The ages of the oldest stars are a key constraint on the evolution of our Galaxy, the history of star formation, and cosmological models. These ages are usually determined from globular clusters. However, it is alternatively possible to determine ages of extreme Population II subgiants in the solar neighborhood based on trigonometric parallaxes, without any recourse to clusters. This approach completely avoids the vexing issues of cluster distances, reddenings, and chemical compositions. There are 3 known nearby, extremely metal-deficient Pop II subgiants with Hipparcos parallax errors of 6-11% which are available for such age determinations. At present, based on the latest isochrones, the derived ages of these stars {HD 84937, HD 132475, and HD 140283} are all close to 14 Gyr, uncomfortably close to or higher than current estimates of the age of the universe. However, the errors in the Hipparcos parallaxes imply uncertainties of at least 2 Gyr in the ages of the 3 stars. We propose to measure parallaxes of these three Pop II subgiants using HST's Fine Guidance Sensor 1R. We expect to reduce the Hipparcos parallax error bars by factors of 5-6, providing the most stringent test yet of current theoretical stellar models of Pop II stars and pushing the age uncertainties to below 0.5 Gyr. These data will also provide a major new constraint on the distance scale of globular clusters, with wide implications for stellar evolution and the calibration of Pop II standard candles. ACS/WFC 10098 Probing the nature of Type Ia SNe through HST astrometry Type Ia supernovae are of key importance in cosmology. Empirical relations allow their use as cosmological standard candles. The generally accepted picture is that the exploding star is a C+O white dwarf which accretes matter from a companion in a binary system. However, the nature of the companion is still unknown. It could either be another WD, or be a giant, subgiant, or main-sequence star. Calculations have shown that it is possible to distinguish among those possibilities by the effect that the supernova explosion has on the companion star. We propose to identify the companion star of the two historical well-known SNeIa through ACS imaging of the targets complemented by WFPC2 observations. A radial-velocity study of the stars in those two Galactic SNeIa has been done from ground-based facilities. To obtain the full motion vector of those stars, we plan to use ACS for high-resolution astrometry in two different epochs. That should allow to detect motion imparted during the explosion in the direction perpendicular to the line of sight, down to a level of a few milliarcsecs/yr. WFPC2 10080 Wavelength Stability of Narrow Band and Linear Ramp Filters Verify the mapping of wavelength as a function of CCD position on LRFs; check for changes in central wavelengths of narrow band filters. 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. 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 10055 ACS Polarization Calibration This proposal aims to address several specific issues for the polarization calibration: {1} variations in calibration with position on the detector {field dependence}, {2} dependence on telescope roll-angle relative to the target, {3} orientation of the polarizer axes, and {4} geometric distortion contributed by the polarizers. ACS/WFC 10006 Black Hole X-ray Novae in M31 During A01-3 we found 22 Black Hole X-ray Novae {BHXN} in M31 using Chandra, and with HST {WFPC2} found two optical counterparts. Our results suggest either a surprisingly high ratio of BH to NS binaries, or a surprisingly high duty cycle for BHXN. We propose to continue this program, with the goals of understanding the relative number of BH vs. NS X-ray binaries in the M31 bulge, and determining the orbital period distribution and duty cycles of these BHXN. Continued observations can determine the duty cycle. The new ACS will allow us to go 2 mags deeper than the WFPC2, and could triple the number of optical counterparts and therefore orbital period estimates. M31 is the only galaxy near enough to allow this extragalactic survey for BHXN. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) None COMPLETED OPS REQs: 17245-2 Battery 1 Capacity Test ( Complete) @ 226/1433z) 17251-0 GenSlew for Prop 10267 slot 14 @226/1458z 17252-0 GenSlew for Prop 9987 slot 1 @226/1459z 17253-0 GenSlew for Prop 9987 slot 2 @226/1501z 17254-0 GenSlew for Prop 9987 slot 3 @226/1502z OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 31 31 FGS REacq 22 22 FHST Update 46 46 LOSS of LOCK SIGNIFICANT EVENTS: Completed Battery 1 Capacity Test @ 226/14:33Z (OR 17245-2). Battery 1 had sufficiently recovered from its discharge to 15 Volts, Voltage, pressure, and loadshare were in family with the other batteries, placed Battery 1 back online in FSW 6-battery system @ 226/14:25Z. The new 6-battery BM SOC is 297 A-h. SOC 1 and SOC 2 safing test values also required updating, modified SOC 1 to 225 A-h and SOC 2 to 170 A-h for. Unmasked the K2 SPA Trim Relay and the proper optimization scheme was reinstated. The EPS is now back in its nominal configuration. The current integrated capacity for Battery 1, as measured through 5.1 Ohm resistor, is 55.3 A-h. Battery 1 was last tested in September 2003 and yielded a capacity of 60.7 A-h. |
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