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Daily Report #4946
HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY REPORT #4946 PERIOD COVERED: 5am October 6 - 5am October 7, 2009 (DOY 279/09:00z-280/09:00z) OBSERVATIONS SCHEDULED COS/FUV 11592 Testing the Origin(s) of the Highly Ionized High-Velocity Clouds: A Survey of Galactic Halo Stars at z3 kpc Cosmological simulation predicts that highly ionized gas plays an important role in the formation and evolution of galaxies and their interplay with the intergalactic medium. The NASA HST and FUSE missions have revealed high-velocity CIV and OVI absorption along extragalactic sightlines through the Galactic halo. These highly ionized high-velocity clouds (HVCs) could cover 85% of the sky and have a detection rate higher than the HI HVCs. Two competing, equally exciting, theories may explain the origin of these highly ionized HVCs: 1) the "Galactic" theory, where the HVCs are the result of feedback processes and trace the disk-halo mass exchange, perhaps including the accretion of matter condensing from an extended corona; 2) the "Local Group" theory, where they are part of the local warm-hot intergalactic medium, representing some of the missing baryonic matter of the Universe. Only direct distance determinations can discriminate between these models. Our group has found that some of these highly ionized HVCs have a Galactic origin, based on STIS observations of one star at z5.3 kpc. We propose an HST FUV spectral survey to search for and characterize the high velocity NV, CIV, and SiIV interstellar absorption toward 24 stars at much larger distances than any previous searches (4d21 kpc, 3|z|13 kpc). COS will provide atomic to highly ionized species (e.g., OI, CII, CIV, SiIV) that can be observed at sufficient resolution (R~22, 000) to not only detect these highly ionized HVCs but also to model their properties and understand their physics and origins. This survey is only possible because of the high sensitivity of COS in the FUV spectral range. COS/FUV/ACS/WFC/WFC3/UV/ 11632 NUV The Gaseous Corona of M31 We propose to obtain ultraviolet spectroscopy of the halo of M31, to probe for a hot corona on scales of 30-40 pc from the galaxy. We seek to obtain absorption line spectra of O I, Mg II, Si II, C IV, and Si IV toward bright QSOs located behind the galaxy. One of the sightlines falls on the projection of Ibata's giant stream. All background sources have been vetted with GALEX photometry and are therefore bright enough for observation. If hot gas is detected with this initial study, we will endeavor to use a grid of background sources to map the structure and kinematics of this gas in detail. M31 is the nearest major spiral galaxy for which such a study can be undertaken, other than our own Milky Way. Recent studies find a substantial population of HI high velocity clouds at distances form M31 of up to 50 kpc, and there is well documented evidence of disrupted satellites and tidal streams. These observations will shed light on the hot gaseous halo of M31, but also will help in interpreting QSO sightlines at high redshift. NIC 11413 NICMOS Mode-2 Coronagraphic Target Acquisition Test NICMOS coronagraphy is extremely sensitive to small centering errors which can result from imperfections in the target acquisition (TA) process. During HST Cycle 7 the on-board (TA) process was augmented which resulted in post-acquisition dispersions of target placements w.r.t. the fiducial position in the occulting system with 1-sigma RSX (a) dispersions of 0.08 mas (or ~ 1/10 pixel) between targets and (b) repeatability of 0.04 mas for identically executed target acquisitions of the same target. This levels of acquisition precision and accuracy are required to enable high-contrast imaging near occulted targets of which the system is capable. This proposal corresponds to SMOV activity NIC-10. NIC1 11205 The Effects of Multiplicity on the Evolution of Young Stellar Objects: A NICMOS Imaging Study We propose to use NICMOS to investigate the multiplicity of young stellar objects (YSOs) in the Orion B molecular cloud. Previous observations with the Spitzer Space Telescope have revealed a remarkable star forming filament near the NGC 2068 reflection nebula. The population of YSOs associated with the filament exhibit a surprisingly wide range of circumstellar evolutionary states, from deeply embedded protostars to T Tauri accretion disks. Many of the circumstellar disks themselves show evidence for significant dust evolution, including grain growth and settling and cleared inner holes, apparently in spite of the very young age of these stars. We will estimate the binary fraction of a representative sample of objects in these various stages of evolution in order to test whether companions may play a significant role in that evolution. NIC1/NIC2/NIC3 11947 Extended Dark Monitoring This program takes a series of darks to obtain darks (including amplifier glow, dark current, and shading profiles) for all three cameras in the read-out sequences used in Cycle 17. A set of 12 orbits will be observed every two months for a total of 72 orbits for a 12 month Cycle 17. This is a continuation of Cycle 16 program 11330 scaled down by ~80%. The first orbit (Visit A0) should be scheduled in the NICMOS SMOV after the DC Transfer Test (11406) and at least 36h before the Filter Wheel Test (11407). Data download using fast track. The following 28 orbits (visit A1-N2) should be scheduled AFTER the SMOV Proposal 11407 (Filter Wheel Test). This is done in order to monitor the dark current following an adjustment of the NCS set-point. These visits should be executed until the final temperature is reached during SMOV. NIC1/NIC2/NIC3 8795 NICMOS Post-SAA Calibration - CR Persistence Part 6 This is 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 'Use After' 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. NIC2/WFC3/IR 11548 Infrared Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation We propose NICMOS and WFC3/IR observations of a sample of 252 protostars identified in the Orion A cloud with the Spitzer Space Telescope. These observations will image the scattered light escaping the protostellar envelopes, providing information on the shapes of outflow cavities, the inclinations of the protostars, and the overall morphologies of the envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron spectra of 75 of the protostars. Combining these new data with existing 3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured with the Spitzer Space Telescope, we will determine the physical properties of the protostars such as envelope density, luminosity, infall rate, and outflow cavity opening angle. By examining how these properties vary with stellar density (i.e. clusters vs. groups vs. isolation) and the properties of the surrounding molecular cloud; we can directly measure how the surrounding environment influences protostellar evolution, and consequently, the formation of stars and planetary systems. Ultimately, this data will guide the development of a theory of protostellar evolution. STIS/CCD 11844 CCD Dark Monitor Part 1 The purpose of this proposal is to monitor the darks for the STIS CCD. STIS/CCD 11846 CCD Bias Monitor-Part 1 The purpose of this proposal is to monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns. STIS/CCD 11849 STIS CCD Hot Pixel Annealing This purpose of this activity is to repair radiation induced hot pixel damage to the STIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation-damaged pixels. Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near -83 deg. C to the ambient instrument temperature (~ +5 deg. C) for several hours. The number of hot pixels repaired is a function of annealing temperature. The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects. WFC3/IR/S/C 11929 IR Dark Current Monitor Analyses of ground test data showed that dark current signals are more reliably removed from science data using darks taken with the same exposure sequences as the science data, than with a single dark current image scaled by desired exposure time. Therefore, dark current images must be collected using all sample sequences that will be used in science observations. These observations will be used to monitor changes in the dark current of the WFC3-IR channel on a day-to-day basis, and to build calibration dark current ramps for each of the sample sequences to be used by GOs in Cycle 17. For each sample sequence/array size combination, a median ramp will be created and delivered to the calibration database system (CDBS). WFC3/UVI/IR 11557 The Nature of Low-Ionization BAL QSOs The rare subclass of optically-selected QSOs known as low-ionization broad absorption line (LoBAL) QSOs show signs of high-velocity gas outflows and reddened continua indicative of dust obscuration. Recent studies show that galaxies hosting LoBAL QSOs tend to be ultraluminous infrared systems that are undergoing mergers, and that have dominant young ( 100 Myr) stellar populations. Such studies support the idea that LoBAL QSOs represent a short- lived phase early in the life of QSOs, when powerful AGN-driven winds are blowing away the dust and gas surrounding the QSO. If so, understanding LoBALs would be critical in the study of phenomena regulating black hole and galaxy evolution, such as AGN feedback and the early stages of nuclear accretion. These results, however, come from very small samples that may have serious selection biases. We are therefore taking a more aggressive approach by conducting a systematic multiwavelength study of a volume limited sample of LoBAL QSOs at 0.5 z 0.6 drawn from SDSS. We propose to image their host galaxies in two bands using WFC3/UVIS and WFC3/IR to study the morphologies for signs of recent tidal interactions and to map their interaction and star forming histories. We will thus determine whether LoBAL QSOs are truly exclusively found in young merging systems that are likely to be in the early stages of nuclear accretion. WFC3/UVIS 11905 WFC3 UVIS CCD Daily Monitor The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS). WFC3/UVIS 11908 Cycle 17: UVIS Bowtie Monitor Ground testing revealed an intermittent hysteresis type effect in the UVIS detector (both CCDs) at the level of ~1%, lasting hours to days. Initially found via an unexpected bowtie-shaped feature in flatfield ratios, subsequent lab tests on similar e2v devices have since shown that it is also present as simply an overall offset across the entire CCD, i.e., a QE offset without any discernable pattern. These lab tests have further revealed that overexposing the detector to count levels several times full well fills the traps and effectively neutralizes the bowtie. Each visit in this proposal acquires a set of three 3x3 binned internal flatfields: the first unsaturated image will be used to detect any bowtie, the second, highly exposed image will neutralize the bowtie if it is present, and the final image will allow for verification that the bowtie is gone. 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 7 7 FGS REAcq 7 7 OBAD with Maneuver 5 5 SIGNIFICANT EVENTS: (None) |
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