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Daily Report #4153
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4153 PERIOD COVERED: UT July 11, 2006 (DOY 192) OBSERVATIONS SCHEDULED ACS/HRC 10512 Search for Binaries Among Faint Jupiter Trojan Asteroids We propose an ambitious SNAPSHOT program to survey faint Jupiter Trojan asteroids for binary companions. We target 150 objects, with the expectation of acquiring data on about 50%. These objects span Vmag = 17.5-19.5, a range inaccessible with ground-based adaptive optics. We now have a significant sample from our survey of brighter Trojans to suggest that the binary fraction is similar to that which we find among brighter main-belt asteroids, roughly 2%. However, our observations suggest a higher binary fraction for smaller main-belt asteroids, probably the result of a different formation mechanism {evident also from the physical characteristics of the binaries}. Because the collision environment among the Trojans is similar to that of the Main Belt, while the composition is likely to be very different, sampling the binary fraction among the fainter Trojans should help us understand the collisional and binary formation mechanisms at work in various populations, including the Kuiper Belt, and help us evaluate theories for the origin of the Trojans. Calibration of and constraints on models of binary production and collisional evolution can only be done using these large-scale, real-life physical systems that we are beginning now to find and utilize. ACS/HRC 10627 A Snapshot Survey of Post-AGB Objects and Proto-Planetary Nebulae We propose an ACS/HRC snapshot survey of 50 post-AGB sources, objects which have evolved from the AGB but may or may not become planetary nebulae {PNe}. This survey will complement existing HST images of proto-planetary nebulae {PPNe} and PNe in addressing circumstellar envelope morphology as a function of: 1} the progenitor star mass; 2} the chemical composition; and 3} evolutionary stage. We will connect the observed diversity of nebualar shapes with the main physical and chemical conditions characterizing post-AGB objects, to identify the mechanism that breaks the symmetry of AGB mass loss. To our knowledge, no previous HST projects have been specifically designed to address this issue. From our database of 360 post-AGB candidates, we have selected approximately 50 targets, none of which have been or are being observed with HST, to sample different central star masses, chemical compositions, and evolutionary stages, uniformly across the sky. These new data will also provide important constraints to a quantitative analysis of Spitzer Space Telescope {SST} observations planned for a similar sample of objects. We will model the HST images and SST spectra using our axisymmetric dust code 2-Dust, to derive dust density distributions, pole to equator density ratios, dust shell masses, inclination angles as well as dust composition. ACS/HRC 10598 ACS Imaging of Fomalhaut: A Rosetta Stone for Debris Disks Sculpted by Planets The Sun and roughly 15% of stars are surrounded by dust disks collisionally replenished by asteroids and comets. Disk structure can be directly tied to the dynamical influence of more massive bodies such as planets. For example, planetary perturbations offset the center of our zodiacal dust disk ~0.01 AU away from the Sun and also maintain a ~40 AU radius inner edge to our Kuiper Belt. Here we propose follow-up observation to the first optical detection of reflected light from dust grains surrounding the nearby star Fomalhaut using HST/ACS. We find a belt of material between 133 and 158 AU radius that has a center position offset ~15 AU from the stellar position, and with a sharp inner edge. A tenuous dust component interior to the belt is also detected in the southeast. Given Fomalhaut's proximity to the Sun {7.7 pc}, these images represent the closest and highest angular resolution view of an extrasolar analog to our Kuiper Belt. The center of symmetry offset and the sharp inner edge of Fomalhaut's belt are evidence for planet-mass objects orbiting the star as predicted by dynamical theory and simulations. We propose comprehensive follow-up ACS imaging to fully exploit this discovery and map the disk around its entire circumference with higher signal-to-noise and at multiple wavelengths. HST/ACS is certainly the only facility capable of performing this relatively wide field optical study at high contrast ratios and diffraction-limited resolution. The Cycle 14 data will provide key measurements of belt width as a function of azimuth, the scattered light color of the belt versus the inner dust component, and the azimuthal structure of the belt. These data will be used to constrain dynamical models of resonances and shepherding that ultimately elucidate the dynamical properties of planet-mass objects in the system. ACS/WFC 10503 The Star Formation Histories of Early Type Dwarf Galaxies in Low Density Environments: Clues from the Sculptor Group We seek HST ACS/WFC time to conduct a detailed study of the stellar populations of 5 early-type {dE, dE/dIrr} dwarf galaxies in the nearby {~1.5 to 4 Mpc} Sculptor group. Four of these systems have been recently found to contain modest amounts of HI, and existing ground-based and HST snapshot data point to the potential presence of small populations of young {blue} stars in at least three of these systems. Consequently, they resemble the Local Group 'transition' objects Phoenix and LGS3. The relative number of such transition systems is thus substantially larger in the low density environment of the Scl group than for the Local Group. Detailed stellar populations studies will allow estimation of the star formation histories, via stellar population modelling of the color- magnitude diagrams, of the target dwarfs, which in turn will connect to gas consumption and retention rates. For the two nearer dwarfs we aim to reach below the horizontal branch {a first for any system beyond the Local Group} equivalent to a main sequence turnoff age of ~1 Gyr. The observations of these two systems will also allow detection of RR Lyrae variables and thus direct confirmation of the presence of old populations. For the other three dwarfs will we cover the first 2.5 mags of the red giant branch, equivalent to the main sequence termination for a ~300 Myr population. The results will have implications for theories of galaxy formation and evolution, particularly with regard to the evolutionary relation between low luminosity dEs and dwarf irregulars. ACS/WFC 10551 Gamma-Ray Bursts from Start to Finish: A Legacy Approach The progenitors of long-duration GRBs are now known to be massive stars. This result lends credence to the collapsar model, where a rotating massive star ends its life leaving a black hole or a highly magnetized neutron star, and confirms its essential aspects. The focus of attention now is on the black hole or magnetar engines that power the bursts. Somehow these engines create the most highly relativistic and highly collimated outflows that we know of, through mechanisms that no current theory can explain. These astrophysical laboratories challenge our understanding of relativistic shocks, of mechanisms for extracting energy from a black hole, and of how physics works in extreme conditions. The launch of Swift is bringing us into a new era, where we can make broadband observations that will enable us to study these fascinating physical processes. We propose here an ambitious, comprehensive program to obtain the datasets that will become the standard that any successful model for the central engine must explain. This programs leverages the HST observations to the maximum extent by our commitment of Swift observations, a Large program at the VLA, and extensive ground-based optical resources. By studying the engines and searching for jets in a variety of events, this program will investigate the conditions necessary for the engine and jet formation itself. ACS/WFC 10753 An Astrometric Calibration Field Near the Ecliptic Pole This program will obtain deep ACS astrometry of a Large Magellanic Cloud star field lying within the planned continuous viewing zone of the James Webb Space Telescope, which extends to a 5 degree radius from the Ecliptic pole. To allow a full astrometric solution to be calculated, controlling for distortions within ACS that may be time variable over periods of months to years, we will observe our target field at two distinct roll angles separated by approximately 90 degrees. To help control for large scale distortions, we will "chop" the observations in at least one roll angle, using offsets of order one third the ACS field of view. FGS 10912 Trigonometric Calibration of the Distance Scale for Classical Novae The distance scale for classical novae is important for understanding the stellar physics of their thermonuclear runaways, their contribution to Galactic nucleosynthesis, and their use as extragalactic standard candles. Although it is known that there is a relationship between their absolute magnitudes at maximum light and their subsequent rates of decline--the well-known maximum-magnitude rate-of-decline {MMRD} relation--it is difficult to set the zero-point for the MMRD because of the very uncertain distances of Galactic novae. We propose to measure precise trigonometric parallaxes for the quiescent remnants of the four nearest classical novae. We will use the Fine Guidance Sensors, which are proven to be capable of measuring parallaxes with errors of ~0.2 mas, well below what is possible from the ground. FGS 10931 Dynamical Masses and Radii of Four White Dwarf Stars No Abstract added NIC1/NC2/NC3 10723 Cycle 14 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 14. This proposal is a slightly modified version of proposal 10380 of cycle 13 and 9993 of cycle12 that we cut down some exposure time to make the observation fit within 24 orbits. NIC2 10906 The Fundamental Plane of Massive Gas-Rich Mergers: II. The QUEST QSOs We propose deep NICMOS H-band imaging of a carefully selected sample of 23 local QSOs. This program is the last critical element of a comprehensive investigation of the most luminous mergers in the nearby universe, the ultraluminous infrared galaxies {ULIRGs} and the quasars. This effort is called QUEST: Quasar / ULIRG Evolutionary STudy. The high-resolution HST images of the QUEST QSOs will complement an identical set of images on the ULIRG sample obtained during Cycle 12, an extensive set of ground-based data that include long-slit NIR spectra from a Large VLT Program, and a large set of mid-infrared spectra from a Cycle 1 medium-size program with Spitzer. This unique dataset will allow us to derive with unprecedented precision structual, kinematic, and activity parameters for a large unbiased sample of objects spanning the entire ULIRG/QSO luminosity function. These data will refine the fundamental plane of massive gas-rich mergers and enable us to answer the following quesitons: {1} Do ultraluminous mergers form elliptical galaxies, and in particular, giant ellipticals? {2} Do ULIRGs evolve into optical bright QSOs? The results from this detailed study of massive mergers in the local universe will be relevant to understanding the basic physical processes involved in creating massive early-type host on the one hand, and growing/feeding embedded massive black holes on the other, in major galaxy mergers. This is an important question since 50% of cosmic star formation at high-z and most of the big BHs appear to be formed in this process. WFPC2 10745 WFPC2 CYCLE 14 INTERNAL MONITOR This calibration proposal is the Cycle 14 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 {both gain 7 and gain 15 -- to test stability of gains and bias levels}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. These also provide raw data for generating annual super-bias reference files for the calibration pipeline. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: #10358 GSACQ(2,1,2) failed, Search Radius Limit Exceeded on FGS 2 @ 192/2203z GSACQ(2,1,2) at 192/21:58:32 failed due to Search Radius Limit Exceeded on FGS 2 at 22:03:11. One 486 status buffer message A05 (FGS Coarse Track failed- Search Radius Limit exceeded) was received. OBAD at 21:53:22 prior to GSACQ had total RSS attitude error correction of 18.09 arcseconds. Observations affected: ACS 84 to 86. COMPLETED OPS REQUEST: #17820-0 Dump ACS Error Log @ 192/1403z #17821-0 Genslew for proposal 10598 - slot 1 @ 192/1908z #17822-0 Genslew for proposal 10598 - slot 2 @ 192/1910z #17823-0 Genslew for proposal 10598 - slot 3 @ 192/1911z #17824-0 Genslew for proposal 10598 - slot 4 @ 192/1912z #17825-0 Genslew for proposal 10598 - slot 5 @ 192/1913z #17826-0 Genslew for proposal 10598 - slot 6 @ 192/1914z #17827-0 Genslew for proposal 10598 - slot 7 @ 192/1915z #17828-0 Genslew for proposal 10598 - slot 8 @ 192/1916z #17818-0 Battery 3 Capacity Test Script & 5 Battery Pressure Limit COP (thru step 18) @ 192/2134z COMPLETED OPS NOTES: #1504-0 Change JERRCNT Limit @ 192/1406z SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 5 4 192/2158z (HSTAR 10358) FGS REacq 7 7 OBAD with Maneuver 20 20 SIGNIFICANT EVENTS: Battery 3 Capacity Test Flash Report #1 Commanding for the Battery 3 Capacity Test started as scheduled on DOY 192/1205 GMT (07/11 at 8:05 am) with setting the Battery Pressure Test for a 5-battery system. Battery 3 was taken off-line and discharged on the first opportunity at 1228 GMT (07/11 at 8:28 am). Following completion of the discharge, Battery 3 will be placed back on-line in hardware during orbit night. Following its recovery period, Battery 3 will be placed back on-line in FSW on 195/1400 GMT (07/14 at 10:00 am). Battery 3 Capacity Test Flash Report #2 The battery 3 high-rate discharge terminated 192/2134 GMT (07/11 at 5:34 pm). The low rate discharge is now in progress and is expected to terminate at approximately 194/1200 (Thursday, 7/13 at 8am). |
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