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Daily Report #4348
Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument usage. This is due to the conversion of previously approved ACS WFC or HRC observations into WFPC2, or NICMOS observations subsequent to the loss of ACS CCD science capability in late January. HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science DAILY REPORT # 4348 PERIOD COVERED: UT April 24, 2007 (DOY 114) OBSERVATIONS SCHEDULED ACS/SBC 10862 Comprehensive Auroral Imaging of Jupiter and Saturn during the International Heliophysical Year A comprehensive set of observations of the auroral emissions from Jupiter and Saturn is proposed for the International Heliophysical Year in 2007, a unique period of especially concentrated measurements of space physics phenomena throughout the solar system. We propose to determine the physical relationship of the various auroral processes at Jupiter and Saturn with conditions in the solar wind at each planet. This can be accomplished with campaigns of observations, with a sampling interval not to exceed one day, covering at least one solar rotation. The solar wind plasma density approaching Jupiter will be measured by the New Horizons spacecraft, and a separate campaign near opposition in May 2007 will determine the effect of large-scale variations in the interplanetary magnetic field {IMF} on the Jovian aurora by extrapolation from near-Earth solar wind measurements. A similar Saturn campaign near opposition in Jan. 2007 will combine extrapolated solar wind data with measurements from a wide range of locations within the Saturn magnetosphere by Cassini. In the course of making these observations, it will be possible to fully map the auroral footprints of Io and the other satellites to determine both the local magnetic field geometry and the controlling factors in the electromagnetic interaction of each satellite with the corotating magnetic field and plasma density. Also in the course of making these observations, the auroral emission properties will be compared with the properties of the near-IR ionospheric emissions {from ground-based observations} and non thermal radio emissions, from ground-based observations for Jupiter?s decametric radiation and Cassini plasma wave measurements of the Saturn Kilometric Radiation {SKR}. ACS/SBC 11074 ACS/SBC Darks in Support of Specific SBC Science Observations This program provides SBC DARK visits to be scheduled in conjuction with certain specific science observations which require the SBC to be turned on in the orbit preceeding the science observation. WFPC2 10917 Afterglows and Environments of Short-Hard Gamma-Ray Bursts Discovery of the first afterglows of short-hard bursts {SHBs} has led to a revolution in our understanding of these events, strongly suggesting that they originate in the mergers of compact-object binaries. Capitalizing on this progress, we propose to pursue the next generation of SHB observations with HST, tracking the decay of all accessible SHB afterglows to late times and pinpointing the location of several more within the context of their host galaxies. These observations will allow quantitative analysis of progenitor lifetimes and short burst environments, enable direct confrontation with population synthesis models, and provide updated event rate estimates for the LIGO and VIRGO gravitational-wave detectors that are now coming on-line. WFPC2 10884 The Dynamical Structure of Ellipticals in the Coma and Abell 262 Clusters We propose to obtain images of 13 relatively luminous early type galaxies in the Coma cluster and Abell 262 for which we have already collected ground based major and minor axis spectra and images. The higher resolution HST images will enable us to study the central regions of these galaxies which is crucial to our dynamical modelling. The complete data set will allow us to perform a full dynamical analysis and to derive the dark matter content and distribution, the stellar orbital structure, and the stellar population properties of these objects, probing the predictions of galaxy formation models. The dynamical analysis will be performed using an up-to-date axi-symmetric orbit superposition code. WFPC2 10890 Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies The formative phase of the most massive galaxies may be extremely luminous, characterized by intense star- and AGN-formation. Till now, few such galaxies have been unambiguously identified at high redshift, restricting us to the study of low-redshift ultraluminous infrared galaxies as possible analogs. We have recently discovered a sample of objects which may indeed represent this early phase in galaxy formation, and are undertaking an extensive multiwavelength study of this population. These objects are bright at mid-IR wavelengths {F[24um]0.8mJy}, but deep ground based imaging suggests extremely faint {and in some cases extended} optical counterparts {R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5, suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain deep ACS F814W and NIC2 F160W images of these sources and their environs in order to determine kpc-scale morphologies and surface photometry for these galaxies. The proposed observations will help us determine whether these extreme objects are merging systems, massive obscured starbursts {with obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted by intrinsically low-luminosity galaxies. WFPC2 11083 The Structure, Formation and Evolution of Galactic Cores and Nuclei A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS}, a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100 early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e., 0.1"-1"}, the HST brightness profiles vary systematically from the brightest giants {which have nearly constant surface brightness cores} to the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the fraction of galaxy mass contributed by the nuclei in the faint galaxies is identical to that contributed by supermassive black holes in the bright galaxies {0.2%}. These findings strongly suggest that a single mechanism is responsible for both types of Central Massive Object: most likely internally or externally modulated gas inflows that feed central black holes or lead to the formation of "nuclear star clusters". Understanding the history of gas accretion, star formation and chemical enrichment on subarcsecond scales has thus emerged as the single most pressing question in the study of nearby galactic nuclei, either active or quiescent. We propose an ambitious HST program {199 orbits} that constitutes the next, obvious step forward: high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging for the complete ACSVCS sample. By capitalizing on HST's unique ability to provide high-resolution images with a sharp and stable PSF at UV and IR wavelengths, we will leverage the existing optical HST data to obtain the most complete picture currently possible for the history of star formation and chemical enrichment on these small scales. Equally important, this program will lead to a significant improvement in the measured structural parameters and density distributions for the stellar nuclei and the underlying galaxies, and provide a sensitive measure of "frosting" by young stars in the galaxy cores. By virtue of its superb image quality and stable PSF, NICMOS is the sole instrument capable of the IR observations proposed here. In the case of the WFPC2 observations, high-resolution UV imaging { 0.1"} is a capability unique to HST, yet one that could be lost at any any time. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: (None) COMPLETED OPS REQUEST: (None) COMPLETED OPS NOTES: (None) SCHEDULED SUCCESSFUL FGS GSacq 09 09 FGS REacq 05 05 OBAD with Maneuver 28 28 SIGNIFICANT EVENTS: Evaluation of Universal Kalman Filter performance continued. Multiple text segments were executed. Details follow. The Kalman Filter (KF) was restarted at 114/11:41 (OR 18045-0) during orbit day, during a vehicle maneuver and during an M2G guiding interval. The filter was activated with the MSS and CSS sensor inputs enabled. All UKF parameters showed nominal operation. The test was an MSS/CSS Initialization Test Case with the vehicle in maneuver and during a fast changing B-field (M_C_IVF, Test #5). Test #9 (M_C_IVP) planned for 114/13:55 was not executed as the forward link could not be scheduled. This test will be rescheduled. The Gyro-1 sensor input was added to the KF at 114/14:30 (OR 18048-2) just after EOD during an F2G guiding interval. The filter was running with the MSS and CSS sensor inputs enabled and converged. All UKF parameters showed nominal operation. The test was an MSS/CSS/Gyro1 test case with the Gyro1 sensor input removed at 114/14:59 with the filter running. The Gyro1 input was removed during an F2G guiding interval, during orbit day and during a fast changing B-field and with no vehicle maneuver (MC_G1_HNF, Test #33). The response to the removal of the gyro input was nominal and the filter remained converged. The removal of the gyro input restored the default MSS/CSS configuration of the filter. Test #10 (M_C_INP) was not executed at 114/18:43 as it was previously and successfully executed at 113/18:44. The execution of Test #16 (MC_G1_IVS) replaced Test #6 (M_C_IVS) at 114/20:00 since Test #6 had been previously and successfully executed at 109/23:34. The KF was restarted at 114/20:00 (OR 18046-0) during orbit day, during a vehicle maneuver and during an M2G guiding interval. The filter was activated with the MSS, CSS and Gyro1 sensor inputs enabled. All UKF parameters showed nominal operation and convergence. The test was an MSS/CSS/Gyro1 Initialization test case during a vehicle maneuver and during a slow changing B-field. The filter was halted, the gyro input selection removed and the filter was restarted at 114/20:22 in the default MSS/CSS configuration. At 114/20:31 the gyro input was added to the KF (OR 18048-2) during orbit night and a T2G guiding interval. The filter was running with the MSS and CSS sensor inputs enabled and with the filter converged. All UKF parameters showed nominal operation. The test was an MSS/CSS/Gyro1 test case with the Gyro1 sensor input removed at 114/21:44 with the filter running. The Gyro1 input was removed during an T2G guiding interval, during orbit day and during a slow changing B-field (MC_G1_HNS, Test #34). The response to the removal of the gyro input was nominal and the filter remained converged. The removal of the gyro input restored the default MSS/CSS configuration of the filter. The Kalman Filter was restarted at 114/23:33 (OR 18045-0) during orbit night, during a vehicle slew and during an M2G guiding interval. The filter was activated with the MSS and CSS sensor inputs enabled, however no CSS signal was present due to orbit night. All UKF parameters showed nominal convergence and steady-state operation. The test was an MSS Only Initialization Test Case with a vehicle maneuver and during a slow changing B-field (M_0_IVS, Test #2). The test above completed testing for the day and left the KF configured in the default MSS/CSS mode. |
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