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Daily Report #4579
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4579 PERIOD COVERED: UT March 31, 2008 (DOY 091) OBSERVATIONS SCHEDULED WFPC2 11024 WFPC2 CYCLE 15 INTERNAL MONITOR This calibration proposal is the Cycle 15 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. FGS 11298 Calibrating Cosmological Chronometers: White Dwarf Masses We propose to use HST/FGS1R to determine White Dwarf {WD} masses. The unmatched resolving power of HST/FGS1R will be utilized to follow up four selected WD binary pairs. This high precision obtained with HST/FGS1R simply cannot be equaled by any ground based technique. This proposed effort complements that done by CoI Nelan in which a sample of WDs is being observed with HST/FGS1R. This proposal will dramatically increase the number of WDs for which dynamical mass measurements are possible, enabling a better calibration of the WD mass-radius relation, cooling curves, initial to final mass relations, and ultimately giving important clues to the star formation history of our Galaxy and the age of its disk as well as in other galaxies. {This project is part of Subasavage's PhD thesis work at Georgia State University.} NIC1/NIC2/NIC3 11330 NICMOS Cycle 16 Extended Dark This takes a series of Darks in parallel to other instruments. NIC1/NIC2/NIC3 8795 NICMOS Post-SAA calibration - CR Persistence Part 6 A new proceedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and everytime 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. NIC3 11120 A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center The Galactic center (GC) is a unique site for a detailed study of a multitude of complex astrophysical phenomena, which may be common to nuclear regions of many galaxies. Observable at resolutions unapproachable in other galaxies, the GC provides an unparalleled opportunity to improve our understanding of the interrelationships of massive stars, young stellar clusters, warm and hot ionized gases, molecular clouds, large scale magnetic fields, and black holes. We propose the first large-scale hydrogen Paschen alpha line survey of the GC using NICMOS on the Hubble Space Telescope. This survey will lead to a high resolution and high sensitivity map of the Paschen alpha line emission in addition to a map of foreground extinction, made by comparing Paschen alpha to radio emission. This survey of the inner 75 pc of the Galaxy will provide an unprecedented and complete search for sites of massive star formation. In particular, we will be able to (1) uncover the distribution of young massive stars in this region, (2) locate the surfaces of adjacent molecular clouds, (3) determine important physical parameters of the ionized gas, (4) identify compact and ultra-compact HII regions throughout the GC. When combined with existing Chandra and Spitzer surveys as well as a wealth of other multi-wavelength observations, the results will allow us to address such questions as where and how massive stars form, how stellar clusters are disrupted, how massive stars shape and heat the surrounding medium, and how various phases of this medium are interspersed. NIC3 11153 The Physical Nature and Age of Lyman Alpha Galaxies In the simplest scenario, strong Lyman alpha emission from high redshift galaxies would indicate that stellar populations younger than 10 Myrs dominate the UV. This does not, however, constrain the stellar populations older than 100 Myrs, which do not contribute to UV light. Also, the Lyman alpha line can be boosted if the interstellar medium is both clumpy and dusty. Different studies with small samples have reached different conclusions about the presence of dust and old stellar populations in Lyman alpha emitters. We propose HST- NICMOS and Spitzer-IRAC photometry of 35 Lyman-alpha galaxies at redshift 4.5z6.5, in order to determine their spectral energy distribution {SED} extending through rest-frame optical. This will allow us to measure accurately {1} The total stellar mass in these objects, including old stars which may have formed at redshifts {z 8} not easily probed by any other means. {2} The dust extinction in the rest-frame UV, and therefore a correction to their present star-formation rates. Taken together, these two quantities will yield the star-formation histories of Lyman alpha galaxies, which form fully half of the known galaxies at z=4-6. They will tell us whether these are young or old galaxies by straddling the 4000A break. Data from NICMOS is essential for these compact and faint {i=25-26th magnitude AB} high redshift galaxies, which are too faint for good near-IR photometry from the ground. WFPC2 11070 WFPC2 CYCLE 15 Standard Darks - part II This dark calibration program obtains dark frames every week in order to provide data for the ongoing calibration of the CCD dark current rate, and to monitor and characterize the evolution of hot pixels. Over an extended period these data will also provide a monitor of radiation damage to the CCDs. 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 time. WFPC2 11128 Time Scales Of Bulge Formation In Nearby Galaxies Traditionally, bulges are thought to fit well into galaxy formation models of hierarchical merging. However, it is now becoming well established that many bulges formed through internal, secular evolution of the disk rather than through mergers. We call these objects pseudobulges. Much is still unknown about pseudobulges, the most pressing questions being: How, exactly, do they build up their mass? How long does it take? And, how many exist? We are after an answer to these questions. If pseudobulges form and evolve over longer periods than the time between mergers, then a significant population of pseudobulges is hard to explain within current galaxy formation theories. A pseudobulge indicates that a galaxy has most likely not undergone a major merger since the formation of the disk. The ages of pseudobulges give us an estimate for the time scale of this quiescent evolution. We propose to use 24 orbits of HST time to complete UBVIH imaging on a sample of 33 nearby galaxies that we have observed with Spitzer in the mid-IR. These data will be used to measure spatially resolved stellar population parameters {mean stellar age, metallicity, and star formation history}; comparing ages to star formation rates allows us to accurately constrain the time scale of pseudobulge formation. Our sample of bulges includes both pseudo- and classical bulges, and evenly samples barred and unbarred galaxies. Most of our sample is imaged, 13 have complete UBVIH coverage; we merely ask to complete missing observations so that we may construct a uniform sample for studying bulge formation. We also wish to compare the stellar population parameters to a variety of bulge and global galaxy properties including star formation rates, dynamics, internal bulge morphology, structure from bulge-disk decompositions, and gas content. Much of this data set is already or is being assembled. This will allow us to derive methods of pseudobulge identification that can be used to accurately count pseudobulges in large surveys. Aside from our own science goals, we will present this broad set of data to the community. Thus, we waive proprietary periods for all observations. WFPC2 11198 Pure Parallel Imaging in the NDWFS Bootes Field The NOAO Deep-Wide Field Survey {NDWFS} Bootes field is the target of one of the most extensive multiwavelength campaigns in astronomy. In addition to ground-based optical and near-infrared imaging, deep radio mapping, and extensive spectroscopy, this entire region has been imaged by the Chandra, Spitzer {IRAC and MIPS}, and GALEX missions. Robust photometric redshifts {calibrated using over 20,000 spectroscopic redshifts} exist for all sources brighter than R=24.5 or than 13 uJy at 4.5 microns. To enhance the value of this data set, we propose pure parallel observations for all approved Cycle 16 programs in this region that lack coordinated parallel observations. The primary aim of this program will be to provide a database useful for the broad range of science programs underway in this region. WFPC2 11229 SEEDS: The Search for Evolution of Emission from Dust in Supernovae with HST and Spitzer The role that massive stars play in the dust content of the Universe is extremely uncertain. It has long been hypothesized that dust can condense within the ejecta of supernovae {SNe}, however there is a frustrating discrepancy between the amounts of dust found in the early Universe, or predicted by nucleation theory, and inferred from SN observations. Our SEEDS collaboration has been carefully revisiting the observational case for dust formation by core- collapse SNe, in order to quantify their role as dust contributors in the early Universe. As dust condenses in expanding SN ejecta, it will increase in optical depth, producing three simultaneously observable phenomena: {1} increasing optical extinction; {2} infrared {IR} excesses; and {3} asymmetric blue-shifted emission lines. Our SEEDS collaboration recently reported all three phenomena occurring in SN2003gd, demonstrating the success of our observing strategy, and permitting us to derive a dust mass of up to 0.02 solar masses created in the SN. To advance our understanding of the origin and evolution of the interstellar dust in galaxies, we propose to use HST's WFPC2 and NICMOS instruments plus Spitzer's photometric instruments to monitor ten recent core-collapse SNe for dust formation and, as a bonus, detect light echoes that can affect the dust mass estimates. These space-borne observations will be supplemented by ground-based spectroscopic monitoring of their optical emission line profiles. These observations would continue our 2-year HST and Spitzer monitoring of this phenomena in order to address two key questions: Do all SNe produce dust? and How much dust do they produce? As all the SN are within 15 Mpc, each SN stands an excellent chance of detection with HST and Spitzer and of resolving potential light echoes. WFPC2 11326 Polarizers Closeout (Internal Observations) Verify stability of polarization calibration. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 11238 - GSAcq(1,3,1) failed to RGA Hold (Gyro Control) GSAcq(1,3,1) scheduled at 091/09:09:04 - 09:17:09 failed to RGA Hold due to (QF1STOPF) stop flag indication on FGS-1. Pre-acquisition OBAD1 (RSS) attitude correction value unavailable due to LOS. OBAD2 had (RSS) value of 9.19arcseconds. Post-acq OBAD/MAP scheduled at 091/10:06:54 had (RSS) value of 2546.26 arcseconds. REACQ(1,3,1) at 10:40:07 was successful. COMPLETED OPS REQUEST: (None) COMPLETED OPS NOTES: (None) SCHEDULED SUCCESSFUL FGS GSacq 10 09 FGS REacq 05 05 OBAD with Maneuver 30 30 SIGNIFICANT EVENTS: (None) |
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