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Daily 3392
HUBBLE SPACE TELESCOPE DAILY REPORT******* # 3392 PERIOD COVERED: DOY 176 OBSERVATIONS SCHEDULED 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. 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. STIS/CCD/MA1 9357 Towards a global understanding of accretion physics --, Clues from an UV spectroscopic survey of cataclysmic variables Accretion inflows and outflows are fundamental phenomena in a wide variety of astrophysical environments, such as Young Stellar Objects, galactic binaries, and AGN. Observationally, cataclysmic variables {CVs} are particularly well suited for the study of accretion processes. We propose to carry out a STIS UV spectroscopic snapshot survey of CVs that fully exploits the diagnostic potential of these objects for our understanding of accretion physics. This survey will provide an homogenous database of accretion disc and wind outflow spectra covering a wide range of mass transfer rates and binary inclinations. We will analyze these spectra with state-of-the-art accretion disc model spectra {SYNDISK}, testing our current knowledge of the accretion disc structure, and, thereby, providing new insight into the so far not well understood process of viscous dissipation. We will use our parameterized wind model PYTHON for the analysis of the radiation driven accretion disc wind spectra, assessing the fundamental question whether the mass loss rate correlates with the disc luminosity. In addition, our survey data will identify a number of systems in which the white dwarf significantly contributes to the UV flux, permitting an analysis of the impact of mass accretion on the evolution of these compact stars. This survey will at least double, if not triple, the number of high-quality accretion disc / wind outflow / accreting white dwarf spectra, and we waive our proprietary rights to permit a timely use of this database. NICMOS 9386 Infrared Photometry of a Statistically Significant Sample of KBOs While the discovery rate of Kuiper Belt objects is accelerating, the physical study of this new region of the solar system has been slowed by a lack of basic astrophysical data. Photometric observations of the majority of the more than 400 known KBOs and Centaurs are rudimentary and incomplete, particularly in the infrared. The multicolor optical-infrared photometry that exists for a small subset of KBOs often shows significant discrepancies between observations by different observers. Their intrinsic faintness puts them at the practical limits of ground-based systems. In July 2001 we began what will be the largest uniform sample of optical photometry of KBOs with a WFPC2 SNAPSHOT program that will perform accurate photometry at V, R, and I on a sample of up to 150 targets. We seek to greatly enhance the value of this survey by obtaining J and H photometry on the same sample using NICMOS. Combined optical and infrared broad band photometry is a far more powerful tool for physical studies than is either alone. Our sample includes objects that will be observed at thermal infrared wavelengths by SIRTF and will be used with those data to derive the first accurate diameters, albedos, and surface properties for a large sample of KBOs. STIS 9431 Composition and history of Beta Pictoris- like circumstellar gaseous disks The gaseous parts of dust disks surrounding main sequence stars have been the subject of intense investigations since 1985. The origin of the gas content was a puzzle around such evolved stars. But the spectral signatures of Beta Pictoris led to the explanation that the gas is probably produced by the evaporation of many small bodies {see Lecavelier et al., 2001, Nature 412, 706}. It is thus believed that BetaPic-like disks are young planetary systems in the clearing-out phase. Our previous HST observations confirmed the presence of gas disks similar to the Beta Pic one. Here we propose new STIS observations of four stars with known circumstellar gas. Four main objectives can be achieved with STIS observations: the determination of the composition of the gas, the investigation of the puzzling high ionization species, the determination of the CO and CI history and monitoring of spectral variability. The analysis of these issues will provide valuable clues to the origin of these gas disks and the subsequent evolution of young planetary systems. In particular, from abundance studies it will be possible to show if the gas is produced by evaporation of bodies like extra-solar comets. STIS 9447 Characterizing the Atmosphere of an Extrasolar Planet HD 209458 b is the first extrasolar planet known to transit the disk of its parent star. Precise measurement of both the photometric transit curve and the radial velocity orbit has allowed for an accurate estimation of the mass, radius, average density, and surface gravity. Numerous theoretical investigations of the planetary atmospheres have been presented in the literature, but no data capable of addressing these has yet been published. We propose to use the method of transmission spectroscopy to constrain greatly models of the planetary atmosphere. We will use STIS to disperse the stellar flux over a large number of detector pixels. The photometric signal is produced by summing the counts over a desired band. For each of twelve bands spanning the UV to the near-IR, we will obtain sufficient precision to detect variations in the transit depth greater than 5 X 10^-5. We have already made a detection of the sodium absorption signature in the planetary atmosphere. With these new data, we will be able to detect, if present, absorption due to Rayleigh scattering, water bands, and/or strong alkali metal lines. These observations will allow us to determine the broad characteristics of the planetary atmosphere. For example, we will be able to distinguish between models with a high cloud deck, and those with no clouds but reduced chemical abundances. ACS 9468 ACS Grism Parallel Survey of Emission- line Galaxies at Redshift z pl 7 We propose an ACS grism parallel survey to search for emission-line galaxies toward 50 random lines of sight over the redshift interval 0 zpl 7. We request ACS parallel observations of duration more than one orbit at high galactic latitude to identify ~ 300 HAlpha emission-line galaxies at 0.2pl zpl 0.5, ~ 720 O IILambda3727 emission-line galaxies at 0.3pl zpl 1.68, and pg 1000 Ly-alpha emission-line galaxies at 3pl zpl 7 with total emission line flux fpg 2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain direct images with the F814W and F606W filters and dispersed images with the WFC/G800L grism at each position. The direct images will serve to provide a zeroth order model both for wavelength calibration of the extracted 1D spectra and for determining extraction apertures of the corresponding dispersed images. The primary scientific objectives are as follows: {1} We will establish a uniform sample of HAlpha and O II emission-line galaxies at z1.7 in order to obtain accurate measurements of co-moving star formation rate density versus redshift over this redshift range. {2} We will study the spatial and statistical distribution of star formation rate intensity in individual galaxies using the spatially resolved emission-line morphology in the grism images. And {3} we will study high-redshift universe using Ly-alpha emitting galaxies identified at z pl 7 in the survey. The data will be available to the community immediately as they are obtained. WFPC2 9595 WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt3/3 This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels. STIS 9606 CCD Dark Monitor-Part 2 Monitor the darks for the STIS CCD. STIS 9608 CCD Bias Monitor - Part 2 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. ACS 9674 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/WFC 9684 The Ultraluminous X-Ray Source in Holmberg II We propose to a program of Chandra and HST observations to test the recent suggestion that the bright X-ray source in Holmberg II is surrounded by a photoionization nebula powered by a central object with a luminosity of order 10^40 erg/s. STIS 9708 STIS Pure Parallel Imaging Program: Cycle 11 This is the default archival pure parallel program for STIS during cycle 11. 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. STIS 9783 The Ages of Nuclear Star Clusters in Early-type Spiral Galaxies We propose to obtain STIS G430L spectra of the previously identified nuclear star cluster in a sample of 16 spiral galaxies of early to intermediate Hubble type. HST's spatial resolution is required to separate the nuclear cluster from the underlying galaxy bulge. Analysis of the spectra with population synthesis methods will reveal the cluster ages. We will use the age distribution to constrain the duty cycle of nuclear cluster formation. Comparison of the results to those for a larger sample of nuclear clusters in late-type, bulgeless galaxies will allow us to investigate possible differences between the formation mechanisms of nuclear clusters in early and late Hubble types. Such differences might be expected because galaxy bulges show a dichotomy: in late Hubble types, the surface brightness profiles are best described by an exponential, while they follow a de Vaucouleurs law in earlier types. Although the reason for this dichotomy is still unknown, it is plausible that galaxy bulges have different formation mechanisms at the two ends of the Hubble sequence. We know that {1} nuclear cluster formation is linked to the funneling of gas towards the nucleus via gravitational torques from stellar bars, {2} a nuclear mass concentration can make bars unstable, and {3} unstable bars can form bulges. Therefore, the age distribution of nuclear star clusters contains important clues to the evolution of galaxy centers and promises new insight into the origin of the Hubble sequence. 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. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTAR 9061:* FGS 1 search exceeded limits (QF1SRLEX and QF1STOPF) @ 176/19:58:36Z and ********************** (QSRCHEXC and QSTOPF) @ 176/19:58:40Z.* There was no acquisition or FGS guiding ********************** scheduled, in gyro hold and in an SAA Level 1 (19:51:29Z).* Prior to event, most ********************** recent GS Acquisition 176/18:36:24Z which was successful with Astrometry on FGS 1. ********************** The term exp occurred @ 176/10:32:35Z.* GS Acquisition preceding the limits event ********************** was successful as well. Under investigation. COMPLETED OPS REQs: NONE OPS NOTES EXECUTED: 1115-0* CCC IP CONFIG Connections @ 176/11:06z ************************ SCHEDULED**** SUCCESSFUL*** FAILURE TIMES FGS GSacq************ 07*********************** 07 FGS REacq************ 09*********************** 09 FHST Update********** 15*********************** 15 LOSS of LOCK SIGNIFICANT EVENTS: None |
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