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Daily Report #4400
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 # 4400 PERIOD COVERED: UT July 9, 2007 (DOY 190) OBSERVATIONS SCHEDULED ACS/SBC 10872 Lyman Continuum Emission in Galaxies at z=1.2 Lyman continuum photons produced in massive starbursts may have played a dominant role in the reionization of the Universe. Starbursts are important contributors to the ionizing metagalactic background at lower redshifts as well. However, their contribution to the background depends upon the fraction of ionizing radiation that escapes from the intrinsic opacity of galaxies below the Lyman limit. Current surveys suggest escape fractions of a few percent, up to 10%, with very few detections {as opposed to upper limits} having been reported. No detections have been reported in the epochs between z=0.1 and z=2. We propose to measure the fraction of escaping Lyman continuum radiation from 15 luminous z~1.2 galaxies in the GOODS fields. Using the tremendous sensitivity of the ACS Solar-blind Channel, we will reach AB=30 mag., allowing us to detect an escape fraction of 1%. We will correlate the amount of escaping radiation with the photometric and morphological properties of the galaxies. A non-detection in all sources would imply that QSOs provide the overwhelming majority of ionizing radiation at z=1.3, and it would strongly indicate that the properties of galaxies at higher redshift have to be significantly different for galaxies to dominate reionization. The deep FUV images will also be useful for extending the FUV study of other galaxies in the GOODS fields. 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. ACS/SBC 10920 High-Resolution Imaging of Nearby Lyman Break Galaxy Analogs in the GALEX All-Sky Survey We have used the ultraviolet all-sky imaging survey currently being conducted by the Galaxy Evolution Explorer {GALEX} to identify for the first time a rare population of low-redshift starbursts with properties remarkably similar to high-redshift Lyman Break Galaxies. These compact UV luminous galaxies {UVLGs} resemble Lyman Break Galaxies in terms of size, UV luminosity, star-formation rate, surface brightness, mass, metallicity, kinematics, dust content, and color. They have characteristic ``ages'' {stellar mass/SFR} of only a few hundred Myr. This population of galaxies is thus worthy of study in its own right and as a sample of local analogs of Lyman Break Galaxies. We propose to image a sample of the 9 nearest and brightest compact UVLGs in the near-ultraviolet, near-infrared, and H-alpha using ACS. With these images we will 1} characterize their structure and morphology, 2} look for signs of interactions and mergers, 3} investigate the distribution and propagation of star formation over varying time scales, and 4} quantify the stellar populations and star formation history, in order to determine whether a previous generation of stars formed long before the current burst. These data will perfectly complement our existing Spitzer, GALEX, and SDSS data, and will provide important information on star-formation in the present-day universe as well as shed light on the earliest major episodes of star formation in high-redshift galaxies. NICMOS 8791 NICMOS Post-SAA calibration - CR Persistence Part 2 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 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. WFPC2 11023 WFPC2 CYCLE 15 Standard Darks - part 1 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 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 11113 Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution The discovery of binaries in the Kuiper Belt and related small body populations is powering a revolutionary step forward in the study of this remote region. Three quarters of the known binaries in the Kuiper Belt have been discovered with HST, most by our snapshot surveys. The statistics derived from this work are beginning to yield surprising and unexpected results. We have found a strong concentration of binaries among low-inclination Classicals, a possible size cutoff to binaries among the Centaurs, an apparent preference for nearly equal mass binaries, and a strong increase in the number of binaries at small separations. We propose to continue this successful program in Cycle 16; we expect to discover at least 13 new binary systems, targeted to subgroups where these discoveries can have the greatest impact. WFPC2 11178 Probing Solar System History with Orbits, Masses, and Colors of Transneptunian Binaries The recent discovery of numerous transneptunian binaries {TNBs} opens a window into dynamical conditions in the protoplanetary disk where they formed as well as the history of subsequent events which sculpted the outer Solar System and emplaced them onto their present day heliocentric orbits. To date, at least 47 TNBs have been discovered, but only about a dozen have had their mutual orbits and separate colors determined, frustrating their use to investigate numerous important scientific questions. The current shortage of data especially cripples scientific investigations requiring statistical comparisons among the ensemble characteristics. We propose to obtain sufficient astrometry and photometry of 23 TNBs to compute their mutual orbits and system masses and to determine separate primary and secondary colors, roughly tripling the sample for which this information is known, as well as extending it to include systems of two near-equal size bodies. To make the most efficient possible use of HST, we will use a Monte Carlo technique to optimally schedule our observations. 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. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: #10884 GSAcq(2,1,2) failed to RGA Hold (Gyro Control). Upon acquisition of signal (AOS) at 190/15:59:30, the GSAcq(2,1,2) scheduled at 190/15:51:38 - 15:59:43 had failed to RGA Hold due to a Search Radius Limit Exceeded Error on FGS-2. Pre-acquisition OBAD1 attitude correction value not available due to LOS. OBAD2 had (RSS) value of 122.17 arcseconds. Post-acq OBAD/MAP (without maneuver) not scheduled. COMPLETED OPS REQUEST: (None) ********************************* SCHEDULED SUCCESSFUL FGS GSacq************************ 8***************** 7 FGS REacq************************ 6***************** 6 OBAD with Maneuver********* *** * 28*************** 28 COMPLETED OPS NOTES: (None) SIGNIFICANT EVENTS: (None) |
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