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Daily Rpt #4414
Notice: Due to the conversion of some ACS WFC or HRC observations into
WFPC2, or NICMOS observations after the loss of ACS CCD science capability in January, there may be an occasional discrepancy between a proposal's listed (and correct) instrument usage and the abstract that follows it. HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science DAILY REPORT # 4414 PERIOD COVERED: UT July 27,28,29, 2007 (DOY 208,209,210) OBSERVATIONS SCHEDULED NIC1/NIC2/NIC3 8794 NICMOS Post-SAA calibration - CR Persistence Part 5 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 DARKs. 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. WFPC2 11314 Calibration of MARCI UV using WFPC2 Ultraviolet imaging is a major unique component of the MARCI experiment on MRO. Unfortunately the calibration of the UV, especially of the 260 nm filter, on MARCI is uncertain due to various unexpected problems during laboratory calibration. Two orbits of WFPC2 observations are requested to properly calibrate the UV using simultaneous MRO / HST observations in a favorable geometry where HST is "looking over the shoulder" of MRO. WFPC2 11307 Completing the ACS Nearby Galaxy Survey with WFPC2 We are requesting 25 orbits of Director's Discretionary Time to complete the primary science goals of our highly-ranked ACS Nearby Galaxy Survey Treasury program {ANGST}. Our program lost ~2/3 of its orbits due to the ACS failure. Roughly half of these were restored as a result of an appeal to the Telescope Time Review Board which re-scoped the program. The Board's response to our appeal was explicit in terms of which targets were to be observed and how. We were directed to request Director's discretionary time for the components of the appeal which were not granted by the Review Board, but which were vital to the success of the program. The observing strategy for ANGST is two-fold: to obtain one deep field per galaxy which enables derivation of an accurate ancient star formation history, and to obtain radial tilings sufficient for recovering the full star formation history. The Review Board granted WFPC2 observations for deep fields in 7 galaxies, but no time for radial tilings. However, recovering the full star formation history of a galaxy is not possible without additional radial coverage. We have searched the archives for observations which may be used in place of the tilings {conceding some of the Treasury goals, but providing significant constraints on the full star formation history}, and have identified suitable observations for all but two of the galaxies. Here we request DD time for radial tilings for those last two galaxies. NIC2 11219 Active Galactic Nuclei in nearby galaxies: a new view of the origin of the radio-loud radio-quiet dichotomy? Using archival HST and Chandra observations of 34 nearby early-type galaxies {drawn from a complete radio selected sample} we have found evidence that the radio-loud/radio-quiet dichotomy is directly connected to the structure of the inner regions of their host galaxies in the following sense: [1] Radio-loud AGN are associated with galaxies with shallow cores in their light profiles [2] Radio-quiet AGN are only hosted by galaxies with steep cusps. Since the brightness profile is determined by the galaxy's evolution, through its merger history, our results suggest that the same process sets the AGN flavor. This provides us with a novel tool to explore the co-evolution of galaxies and supermassive black holes, and it opens a new path to understand the origin of the radio-loud/radio-quiet AGN dichotomy. Currently our analysis is statistically incomplete as the brightness profile is not available for 82 of the 116 targets. Most galaxies were not observed with HST, while in some cases the study is obstructed by the presence of dust features. We here propose to perform an infrared NICMOS snapshot survey of these 82 galaxies. This will enable us to i} test the reality of the dichotomic behavior in a substantially larger sample; ii} extend the comparison between radio-loud and radio-quiet AGN to a larger range of luminosities. WFPC2 11202 The Structure of Early-type Galaxies: 0.1-100 Effective Radii The structure, formation and evolution of early-type galaxies is still largely an open problem in cosmology: how does the Universe evolve from large linear scales dominated by dark matter to the highly non-linear scales of galaxies, where baryons and dark matter both play important, interacting, roles? To understand the complex physical processes involved in their formation scenario, and why they have the tight scaling relations that we observe today {e.g. the Fundamental Plane}, it is critically important not only to understand their stellar structure, but also their dark-matter distribution from the smallest to the largest scales. Over the last three years the SLACS collaboration has developed a toolbox to tackle these issues in a unique and encompassing way by combining new non-parametric strong lensing techniques, stellar dynamics, and most recently weak gravitational lensing, with high-quality Hubble Space Telescope imaging and VLT/Keck spectroscopic data of early-type lens systems. This allows us to break degeneracies that are inherent to each of these techniques separately and probe the mass structure of early-type galaxies from 0.1 to 100 effective radii. The large dynamic range to which lensing is sensitive allows us both to probe the clumpy substructure of these galaxies, as well as their low-density outer haloes. These methods have convincingly been demonstrated, by our team, using smaller pilot-samples of SLACS lens systems with HST data. In this proposal, we request observing time with WFPC2 and NICMOS to observe 53 strong lens systems from SLACS, to obtain complete multi-color imaging for each system. This would bring the total number of SLACS lens systems to 87 with completed HST imaging and effectively doubles the known number of galaxy-scale strong lenses. The deep HST images enable us to fully exploit our new techniques, beat down low-number statistics, and probe the structure and evolution of early- type galaxies, not only with a uniform data-set an order of magnitude larger than what is available now, but also with a fully coherent and self-consistent methodological approach! WFPC2/NIC3 11188 First Resolved Imaging of Escaping Lyman Continuum The emission from star-forming galaxies appears to be responsible for reionization of the universe at z6. However, the models that attempt to describe the detailed impact of high- redshift galaxies on the surrounding inter-galactic medium {IGM} are strongly dependent upon several uncertain parameters. Perhaps the most uncertain is the fraction of HI-ionizing photons produced by young stars which escape into the IGM. Most attempts to measure this "escape fraction" {f_esc} have produced null results. Recently, a small subset of z~3 Lyman Break Galaxies {LBGs} has been found exhibiting large escape fractions. It remains unclear however, what differentiates them from other LBGs. Several models attempt to explain how such a large fraction of ionizing continuum can escape through the HI and dust in the ISM {eg. "chimneys" created by SNe winds, globular cluster formation, etc.}, each producing unique signatures which can be observed with resolved imaging of the escaping Lyman continuum. We propose a deep, high resolution WFPC2 image of the ionizing continuum {F336W} and the rest-frame 1500 Angstrom continuum {F606W} of five of the six known LBGs with large escape fractions. These LBGs all fit within a single WFPC2 pointing, yielding high observing efficiency. Additionally, they all have z~3.1 or higher, the optimal redshift range for probing the Lyman Continuum region with available WFPC2 filters. These factors make our proposed sample especially suitable for follow- up. With these data we will discern the mechanisms responsible for producing large escape fractions, and therefore gain insight into the process of reionization. WFPC2 11176 Location and the Origin of Short Gamma-Ray Bursts During the past decade extraordinary progress has been made in determining the origin of long- duration gamma-ray bursts. It has been conclusively shown that these objects derive from the deaths of massive stars. Nonetheless, the origin of their observational cousins, short-duration gamma-ray bursts {SGRBs} remains a mystery. While SGRBs are widely thought to result from the inspiral of compact binaries, this is a conjecture. A number of hosts of SGRBs have been identified, and have been used by some to argue that SGRBs derive primarily from an ancient population {~ 5 Gyr}; however, it is not known whether this conclusion more accurately reflects selection biases or astrophysics. Here we propose to employ a variant of a technique that we pioneered and used to great effect in elucidating the origins of long-duration bursts. We will examine the degree to which SGRB locations trace the red or blue light of their hosts, and thus old or young stellar populations. This approach will allow us to study the demographics of the SGRB population in a manner largely free of the distance dependent selection effects which have so far bedeviled this field, and should give direct insight into the age of the SGRB progenitor population. NIC2 11152 Probing the compact dust disk of a nearby Classical T Tauri Star BP Psc is a high Galactic latitude {b = -57}, bright, IRAS source that generally has been classified as a T Tauri star but little studied to date. We have carried out a multiwavelength ground-based study of this object and find that it is most likely a ~10 Myr classical T Tauri star surrounded by a gas and dust disk, and less than 100 pc from Earth, making it one of the oldest and closest such stars known. Near-IR AO images and IR photometry show it is surrounded by an compact {0.2"}, almost-edge-on, optically thick disk of dust with a wide range of temperatures. We propose a multiwavelength polarimetric study of the compact disk to support quantitative modeling to recover disk and dust parameters. We also propose coronagraphic imaging to search for larger- scale dust structures invisible in ground-based images, and narrowband imaging of an outflow jet and associated Herbig-Haro objects to study their structure and determine a kinematic distance of the system. A massive compact disk surrounding an isolated 10 Myr star is a unique environment for planet formation, and its proximity to Earth allows HST to study it in detail. WFPC2 11118 Investigating Near-Equinox Atmospheric Change on Uranus Uranus is approaching its 7 December 2007 equinox, when we will be able to observe the entire northern hemisphere for the first time with modern cameras. The large seasonal phase shift expected from its long radiative time constant implies that it should now exhibit nearly maximal hemispheric contrast, and should be in the process of reversing. Many changes already observed, such as the development of the first visible-wavelength dark spot, discovered in Cycle 15, and the fading of the south polar cap may be indicative of the expected reversal. We propose a detailed characterization of Uranus' current seasonal response with a 7-orbit program consisting of 1 orbit of NICMOS imaging of cloud bands and 6 orbits of WFPC2 imaging using both broadband and narrow-band filters capable of tracking dark and bright discrete cloud features. Filters between 0.467 and 1.87 microns will provide vertical sensing depths scanning through the pressure range where the putative methane and deeper H2S clouds might plausibly exist and provide strong constraints on their contributions and parent gas mixing ratios. These observations have unique combinations of spectral range and resolution with needed temporal and spatial resolution not available from groundbased observations. Only HST is capable of investigating the Uranus dark spot. WFPC2 11100 Two new `bullets' for MOND: revealing the properties of dark matter in massive merging clusters The principal objective of this proposal is to study the physical nature of dark matter by using two, massive, newly-identified merging clusters of galaxies. As shown by the pioneering example of the ``bullet cluster'' {1E0657-56}, such systems are ideal laboratories for detecting dark matter and distinguishing between cold dark matter {CDM} and other scenarios {e.g. self- interacting dark matter}. Our limit on the self-interaction cross-section of dark matter relies on the assumption of a normal pre-merger mass-to-light ratios, and a small impact parameter during the collision of the two clusters. In order to mitigate any possible systematic effects, it is vital to extend this work to other, similar systems. With detailed observations of new systems, the systematic uncertainties in the dark matter cross section calculations can be improved substantially, allowing us to move from rough order of magnitude estimates to measurements with quantifiable uncertainties that can be compared usefully with the predictions from numerical simulations. Our targets are two extraordinary, high-redshift, merging galaxy clusters recently discovered by the Massive Cluster Survey {MACS}. This survey is by far the best matched to this study, since it selects medium redshift {optimal for gravitational lensing studies} and X-ray luminous {hence massive} objects. We have selected the best candidates with clear evidence for considerable offsets between the hot X-ray emitting gas and optically luminous stellar material. The two most striking examples are the targets of this proposal. To pin down the position of the dark matter component we require high resolution, absolutely calibrated mass maps. The combination of weak and strong lensing measurements is needed to attain this goal. This can only be achieved with the excellent resolving power of the HST {in combination with wide-field, multicolor Subaru data already in hand}. We therefore request multicolor HST/WFPC2 observations of the two merging clusters. The combination of constraints from multiply lensed images {identified via morphology and color information} and high-resolution weak lensing data will allow us to construct, self-consistently, their mass distribution from the very centers to the outskirts. Gravitational lensing thus provides a unique tool transforming these clusters into dark matter laboratories. They will supply us with answers as to the nature and properties of dark matter, and how it shapes galaxies and galaxy clusters and their evolution through cosmic time. WFPC2 11079 Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys We propose to use WFPC2 to image the most interesting star-forming regions in the Local Group galaxies, to resolve their young stellar populations. We will use a set of filters including F170W, which is critical to detect and characterize the most massive stars, to whose hot temperatures colors at longer wavelengths are not sensitive. WFPC2's field of view ideally matches the typical size of the star-forming regions, and its spatial resolution allows us to measure individual stars, given the proximity of these galaxies. The resulting H-R diagrams will enable studies of star- formation properties in these regions, which cover largely differing metallicities {a factor of 17, compared to the factor of 4 explored so far} and characteristics. The results will further our understanding of the star-formation process, of the interplay between massive stars and environment, the properties of dust, and will provide the key to interpret integrated measurements of star-formation indicators {UV, IR, Halpha} available for several hundreds more distant galaxies. Our recent deep surveys of these galaxies with GALEX {FUV, NUV} and ground-based imaging {UBVRI, Halpha, [OIII] and [SII]} provided the identification of the most relevant SF sites. In addition to our scientific analysis, we will provide catalogs of HST photometry in 6 bands, matched corollary ground-based data, and UV, Halpha and IR integrated measurements of the associations, for comparison of integrated star-formation indices to the resolved populations. We envisage an EPO component. WFPC2 11033 Full Moon Earth Flats Closeout Flat field exposures will be obtained by observing the moonlit Earth with the broadband WFPC2 filters F606W and F814W, which saturate in the minimum exposure time on the sunlit Earth. These observations will be used to improve the flats currently in the pipeline and are part of the WFPC2 closeout operations. Because CTE effects are large for star flats and small for full field illumination, Earth flats are the superior technique. WFPC2 10583 Resolving the LMC Microlensing Puzzle: Where Are the Lensing Objects ? We are requesting 32 HST orbits to help ascertain the nature of the population that gives rise to the observed set of microlensing events towards the LMC. The SuperMACHO project is an ongoing ground-based survey on the CTIO 4m that has demonstrated the ability to detect LMC microlensing events in real-time via frame subtraction. The improvement in angular resolution and photometric accuracy available from HST will allow us to 1} confirm that the detected flux excursions arise from LMC source stars rather than extended objects {such as for background supernovae or AGN}, and 2} obtain reliable baseline flux measurements for the objects in their unlensed state. The latter measurement is important to resolve degeneracies between the event timescale and baseline flux, which will yield a tighter constraint on the microlensing optical depth. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: #10918 REacq(1,2,1) failed to RGA Control (Gyro Control). REacq(1,2,1) scheduled at 209/13:56:20 - 14:04:25 failed to RGA Hold due to (QF1STOPF) stop flag indication on FGS-1. Pre-acq OBADs showed (RSS) attitude correction values of 888.95 and 17.77 arcseconds. Prior GSAcq(1,2,1) of 209/12:40:12 was successful. Post-acq OBAD/MAP had (RSS) value of 10.04 arcseconds. REacq(1,2,1) at 209/15:33:00 was successful. Upon acquisition of signal at 209/17:23:59, HST was in Gyro Control with QF1STOPF and STOP flags set. REacq(1,2,1) at 209/17:08:53 failed to RGA Hold. #10919 GSAcq(1,3,3) results in fine lock backup (1,0,1). Upon acquisition of signal at 209/19:08:11, the GSAcq(1,3,3) scheduled at 209/18:49:46 - 18:57:51 had resulted in fine lock backup (1,0,1) using FGS-1 due to (QF3STOPF) stop flag indication on the secondary FGS-3. Pre-acq OBADs (RSS) attitude correction values not available due to LOS. Post-acq OBAD/MAP showed (RSS) value of 13.60 arcseconds. Subsequent REacq(1,3,3) scheduled at 209/20:24:07 resulted in fine lock backup (1,0,1) using FGS-1 due to QF3STOPF stop flag indication on FGS-3. Pre-acq OBADs were successful. #10920 GSAcq (1,2,1) failed to RGA Hold (Gyro Control) AT AOS 209/22:27:15 GSAcq (1,2,1) had failed to RGA Hold (Gyro Control) with stop flags "QSTOP & QF1STOPF". OBAD #1 & 2 data unavailable until engineering data dump is accomplished. OBAD MAP: v1 6.30, V2 -0.41, V3 1.11, RSS 6.41. At AOS 210/01:04:16 REAcq (1,2,1) scheduled from 209/23:32:20-23:39:50 had failed to RGA Hold (Gyro Control) with stop flags "QSTOP & QF1STOPF". OBAD data unavailable due to LOS. REAcq (1,2,1) scheduled from 210/01:08:14-01:15:44 failed to RGA Hold (Gyro Control) with stop flags "QSTOP & QF1STOPF". FGS 1 reached a PMT count high of 6393.00244. OBAD #1: V1 -71.68, V2 -770.33, V3 -15.23, RSS 773.81 OBAD #2: V1 2.32, V2 0.99, V3 -12.84, RSS 13.08 OBAD MAP: not scheduled Note: The same guide star pair used in HSTAR 10918 COMPLETED OPS REQUEST: (None) **************************** SCHEDULED SUCCESSFUL FGS GSacq******************* 22******** 21 FGS REacq******************* 20******** 16 OBAD with Maneuver***** 84******** 84 COMPLETED OPS NOTES: (None) SIGNIFICANT EVENTS: (None) |
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