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Daily 3496
HUBBLE SPACE TELESCOPE
DAILY REPORT # 3496 PERIOD COVERED: DOY 328 OBSERVATIONS SCHEDULED ACS 9984 Cosmic Shear With ACS Pure Parallels Small distortions in the shapes of background galaxies by foreground mass provide a powerful method of directly measuring the amount and distribution of dark matter. Several groups have recently detected this weak lensing by large-scale structure, also called cosmic shear. The high resolution and sensitivity of HST/ACS provide a unique opportunity to measure cosmic shear accurately on small scales. Using 260 parallel orbits in Sloan textiti {F775W} we will measure for the first time: beginlistosetlength sep0cm setlengthemsep0cm setlength opsep0cm em the cosmic shear variance on scales 0.7 arcmin, em the skewness of the shear distribution, and em the magnification effect. endlist Our measurements will determine the amplitude of the mass power spectrum sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20, and the mass density Omega_m with s/n=4. They will be done at small angular scales where non-linear effects dominate the power spectrum, providing a test of the gravitational instability paradigm for structure formation. Measurements on these scales are not possible from the ground, because of the systematic effects induced by PSF smearing from seeing. Having many independent lines of sight reduces the uncertainty due to cosmic variance, making parallel observations ideal. ACS/HRC 10050 ACS Earth Flats High signal sky flats will be obtained by observing the bright Earth with the HRC and WFC. These observations will be used to verify the accuracy of the flats currently used by the pipeline and will provide a comparison with flats derived via other techniques: L-flats from stellar observations, sky flats from stacked GO observations, and internal flats using the calibration lamps. Weekly coronographic monitoring is required to assess the changing position of the spots. ACS/HRC/WFC 10042 CCD Daily Monitor This program consists of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. This programme will be executed once a day for the entire lifetime of ACS. ACS/HRC/WFC 9764 Elliptical galaxies in z~1.5 clusters Giant elliptical galaxies offer can some of the tightest constraints on models of galaxy formation. Recent observations have shown significant inconsistencies between their properties and the predictions of the currently popular hierarchical clustering models. Many outstanding questions about the nature and evolution of these objects can best {or only} be addressed by extending studies of cluster ellipticals out to z1. Recently we have identified large overdensities of red galaxies, strongly clustered around powerful radio sources at z~1.5. We propose to image our two richest fields, of Abell Class 0-1 richness, using the F814W and F606W filters on the ACS/WFC. Our goals are to investigate: {1} Galaxy morphologies: we will determine the bulge fractions of the red cluster galaxies, to confirm that they are early-types, and measure their characteristic radii to investigate their evolutionary status. {2} Colour gradients: we will search for colour gradients indicative of recent star formation {particularly blue cores}, or inhomogeneities in the internal colours which might be indicative of recent assembly. {3} Cluster membership: with two additional colours we will obtain accurate photometric redshift estimates for all galaxies. Combined with studies of nearby clusters and of field ellipticals, our results will place very tight constraints on the formation of the most massive galaxies. FGS 9329 The Masses and Luminosities of Population II Stars Very little is currently known concerning the mass-luminosity relation {MLR} of Population II stars. However, with the advent of the Hipparcos Catalogue, improved distances to many spectroscopic binaries known to be Pop II systems are now available. After surveying the literature and making reasonable estimates of the secondary masses, we find 13 systems whose minimum separation should be larger than the resolution limit of FGS1. Because of the expected magnitude differences and separations, it is not possible to resolve the systems from the ground. We therefore propose FGS observations of the sample. In combination with the known spectroscopic orbits and Hipparcos distances, these observations will yield up to 26 precise stellar mass determinations of metal-poor stars, if all systems are resolved and the relative orbits are determined. A combination of FGS data and ground-based observations will lead to component luminosities and effective temperatures. This program will allow for a significantly better understanding of the Pop II main sequence, which in turn will lead to better ages and distances of the galactic globular clusters, and a Pop II MLR will be constructed for the first time. NIC/NIC3 9865 The NICMOS Parallel Observing Program We propose to continue managing the NICMOS pure parallel program. Based on our experience, we are well prepared to make optimal use of the parallel opportunities. The improved sensitivity and efficiency of our observations will substantially increase the number of line-emitting galaxies detected. As our previous work has demonstrated, the most frequently detected line is Halpha at 0.7z1.9, which provides an excellent measure of current star formation rate. We will also detect star-forming and active galaxies in other redshift ranges using other emission lines. The grism observations will produce by far the best available Halpha luminosity functions over the crucial--but poorly observed--redshift range where galaxies appear to have assembled most of their stellar mass. This key process of galaxy evolution needs to be studied with IR data; we found that observations at shorter wavelengths appear to have missed a large fraction of the star-formation in galaxies, due to dust reddening. We will also obtain deep F110W and F160W images, to examine the space densities and morphologies of faint red galaxies. In addition to carrying out the public parallels, we will make the fully reduced and calibrated images and spectra available on-line, with some ground-based data for the deepest parallel fields included. NICMOS 8790 NICMOS Post-SAA calibration - CR Persistence Part 1. 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. STIS/CCD 10017 CCD Dark Monitor-Part 1 Monitor the darks for the STIS CCD. STIS/CCD 10019 CCD Bias Monitor - Part 1 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 10022 STIS CCD Hot Pixel Annealing Cycle 12 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. In addition CTE performance is examined by looking for traps in a low signal level flat. Follows on from proposal 9612. STIS/CCD/MA1 10081 Is the exoplanet HD209458b's exosphere in a blowoff state ? Using HST Lyman alpha observations, we have detected an extended tail shaped upper atmosphere around the extra-solar planet HD209458b. The Cycle 10 STIS G140M observations revealed an absorption of 15+/-4% of the stellar Lyman alpha emission line during the planetary transit in front of the star {Vidal-Madjar, et al. 2003}. This showed that HI evaporation is taking place within a highly extended upper atmosphere. Very recent studies on the evaporation mechanism are now indicating that instead of ``Jeans escape'' a more probable mechanism is complete atmospheric ``blowoff'' as suffered by the telluric planets in the early solar system. This mecanism could be directly tested with HST by searching for the escape of species slightly heavier than HI. It is easy to show that neither oxygen nor carbon would be detected with HST if only ``Jeans escape'' takes place while both species, under ``blowoff'' conditions, should reach the Roche limit of the planet and escape as hydrogen. If this is the case an absorption during transit of about 15% should be observed for both. Twelve orbits with the STIS G140L spectrograph will allow us to detect the presence of these species during three transits with a better than 5% accuracy, needed to detect an object of the size of the planetary Roche lobe. Simultaneously these observations will confirm and give more precision about the extention of the HI cometary like tail expected to occult the star well after the end of the visible transit. This proposed investigation is a unique opportunity to further study hot giant planets upper atmospheres, reveal the precise evaporation mechanism and give new constraints on the ``hot Jupiters'' lifetime. This could explain the lack of planets discovered so far at less than 0.04~AU from their star. We ask for HST observations under Director Discretionnary time to have access to the coming transits observable in the early fall of 2003. STIS/CCD/MA1 9759 Confirmation of New Candidates for the Study of Intergalactic Helium The reionization of intergalactic helium is believed to take place between redshift 3 and 4. The study of HeII Lyman-alpha absorption in four quasars at 2.7z3.3 demonstrates the great potential of such an intergalactic-medium {IGM} probe and suggests that the reionization epoch is at higher redshifts. Clean quasar sightlines may be found only from massive pre-selection processes in the optical and UV, because of random, severe absorption by intervening Lyman-limit systems. The SDSS has discovered approximately 36000 quasars, and we propose to verify the UV detectability in 70 top candidates for helium studies extending to even higher redshift. Our proposed approach has already proven successful, and additional positive confirmations will allow follow-up observations, with STIS or COS, to pinpoint the epoch of reionization of the IGM, and the evolution of its properties near that period. WFPC2 10068 WFPC2 CYCLE 12 Standard Darks 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 10069 WFPC2 CYCLE 12 Supplemental Darks, Part 1/3 This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels. WFPC2 10072 WFPC2 CYCLE 12 INTERNAL MONITOR This calibration proposal is the Cycle 12 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 {gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. WFPC2 10075 WFPC2 CYCLE 12 Intflat and Viflat Sweeps and Filter Rotation Anomaly Monitor Using intflat observations, this WFPC2 proposal is designed to monitor the pixel-to-pixel flatfield response and provide a linearity check. The intflat sequences, to be done once during the year, are similar to those from the Cycle 11 program 9597. The images will provide a backup database in the event of complete failure of the visflat lamp as well as allow monitoring of the gain ratios. The sweep is a complete set of internal flats, cycling through both shutter blades and both gains. The linearity test consists of a series of intflats in F555W, in each gain and each shutter. As in Cycle 11, we plan to continue to take extra visflat, intflat, and earthflat exposures to test the repeatability of filter wheel motions. WFPC2 10082 POMS Test Proposal: WFII backup parallel archive proposal This is a POMS test proposal designed to simulate scientific plans WFPC2 9709 POMS Test Proposal: WFII parallel archive proposal This is the generic target version of the WFPC2 Archival Pure Parallel program. The program will be used to take parallel images of random areas of the sky, following the recommendations of the 2002 Parallels Working Group. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) None COMPLETED OPS REQs: None OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 08 08 FGS REacq 13 13 FHST Update 12 12 LOSS of LOCK SIGNIFICANT EVENTS: Autonomous FGS ITS on-board testing (Proposal 04974) FGS 1 @ 329/12:30Z - 12:38Z (Visit 11) and FGS 3 @ 329/12:48Z - 12:56Z (Visit 12). |
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