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Daily 3716
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3716 PERIOD COVERED: DOY 288 OBSERVATIONS SCHEDULED ACS/HRC 10182 Towards a Comprehensive Understanding of Type Ia Supernovae: The Necessity of UV Observations Type Ia supernovae {SNe Ia} are very important to many diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology which led to the discovery of dark energy and the accelerating Universe. However, the utility of SNe Ia as cosmological probes depends on the degree of our understanding of SN Ia physics, and various systematic effects such as cosmic chemical evolution. At present, the progenitors of SNe Ia and the exact explosion mechanisms are still poorly understood, as are evolutionary effects on SN Ia peak luminosities. Since early-time UV spectra and light curves of nearby SNe Ia can directly address these questions, we propose an approach consisting of two observational components: {1} Detailed studies of two very bright, young, nearby SNe Ia with HST UV spectroscopy at 13 epochs within the first 1.5 months after discovery; and {2} studies of correlations with luminosity for five somewhat more distant Hubble-flow SNe Ia, for which relative luminosities can be determined with precision, using 8 epochs of HST UV spectroscopy and/or broad-band imaging. The HST data, along with extensive ground-based optical to near-IR observations, will be analyzed with state-of-the-art models to probe SN Ia explosion physics and constrain the nature of the progenitors. The results will form the basis for the next phase of precision cosmology measurements using SNe Ia, allowing us to more fully capitalize on the substantial past {and future} investments of time made with HST in observations of high-redshift SNe Ia. ACS/HRC 9792 Uncovering the CV population in M15: a deep, time-resolved, far-UV survey of the cluster core We propose to carry out a deep, far-ultraviolet {FUV}, time-resolved for faint cataclysmic variables {CVs} and other dynamically-formed objects in the globular cluster {GC} M15. We will use the ACS/SBC to carry out 6 epochs of FUV imaging of this cluster in a single filter, and will use two additional visits to obtain images in other FUV and NUV filters. Since crowding is not a problem in the FUV, this will yield time-resolved FUV photometry of all blue objects in the cluster core. Our CV census will be both deep enough to be essentially complete and ``broad'' enough to involve all of the following CV characteristics: {1} UV brightness; {2} blue FUV spectral shape; {3} strong CIV and HeII emission; {4} short time-scale {$sim$ minutes} variability {flickering, WD spin}; {6} intermediate time-scale {$sim$ hours} variability {orbital variations}; {7} long time-scale {$sim$ weeks} variability {dwarf nova eruptions}. We will thus find the CV population in M15, if it exists. In addition, our survey will detect numerous blue stragglers and hot white dwarfs, as well as any other blue objects near the core. Finally, our photometry will yield high-quality FUV light curves of the two low-mass x-ray binaries in M15. ACS/WFC/WFPC2 10092 The COSMOS 2-Degree ACS Survey We will undertake a 2 square degree imaging survey {Cosmic Evolution Survey -- COSMOS} with ACS in the I {F814W} band of the VIMOS equatorial field. This wide field survey is essential to understand the interplay between Large Scale Structure {LSS} evolution and the formation of galaxies, dark matter and AGNs and is the one region of parameter space completely unexplored at present by HST. The equatorial field was selected for its accessibility to all ground-based telescopes and low IR background and because it will eventually contain ~100, 000 galaxy spectra from the VLT-VIMOS instrument. The imaging will detect over 2 million objects with I 27 mag {AB, 10 sigma}, over 35, 000 Lyman Break Galaxies {LBGs} and extremely red galaxies out to z ~ 5. COSMOS is the only HST project specifically designed to probe the formation and evolution of structures ranging from galaxies up to Coma-size clusters in the epoch of peak galaxy, AGN, star and cluster formation {z ~0.5 to 3}. The size of the largest structures necessitate the 2 degree field. Our team is committed to the assembly of several public ancillary datasets including the optical spectra, deep XMM and VLA imaging, ground-based optical/IR imaging, UV imaging from GALEX and IR data from SIRTF. Combining the full-spectrum multiwavelength imaging and spectroscopic coverage with ACS sub-kpc resolution, COSMOS will be Hubble's ultimate legacy for understanding the evolution of both the visible and dark universe. NIC/NIC3 10226 The NICMOS Grism Parallel Survey 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. NIC1/NIC2/NIC3 8793 NICMOS Post-SAA calibration - CR Persistence Part 4 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. NIC2 10160 The nuclear scattering geometry of Seyfert galaxies Orientation-based unification schemes are now well-established as the basis for understanding the relationships between different classes of AGN. However, our recent study of the optical polarization properties of Seyfert 1 galaxies indicates that scattered light emerging from these objects often follows a different path to that in Seyfert 2's, indicating that the simplest unification geometry is incomplete. We have developed a generic scattering model for Seyfert nuclei which includes a compact, equatorial scattering region located within the circum-nuclear torus and the 'classic' polar scattering region outside it. We propose to test this model by using NICMOS to make NIR imaging observations that will allow us to isolate the two scattering regions within individual objects. NIC3 10337 The COSMOS 2-Degree ACS Survey NICMOS Parallels The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a companion to program 10092. WFPC2 10170 Atmospheric Variability on Uranus and Neptune We propose Snapshot observations of Uranus and Neptune to monitor changes in their atmospheres on time scales of weeks, months, and years. Uranus is rapidly approaching equinox in 2007, with another 4 degrees of latitude becoming visible every year. Recent HST observations during this epoch {including 6818: Hammel, Lockwood, and Rages; 7885: Hammel, Karkoschka, and Marley; 8680: Hammel, Rages, Lockwood, and Marley; and 8634: Rages, Hammel, Lockwood, Marley, and McKay} have revealed strongly wavelength-dependent latitudinal structure and the presence of numerous visible-wavelength cloud features in the northern hemisphere. Long-term ground-based observations {Lockwood and Thompson 1999} show seasonal brightness changes whose origins are not well understood. Recent near-IR images of Neptune obtained using adaptive optics on the Keck Telescope together with images from our Cycle 9 Snapshot program {8634} show a general increase in activity at south temperate latitudes as well as the possible development of another Great Dark Spot. Further Snapshot observations of these two dynamic planets will elucidate the nature of long-term changes in their zonal atmospheric bands and clarify the processes of formation, evolution, and dissipation of discrete albedo features. 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 12 12 FGS Reacq 02 02 FHST Update 15 15 LOSS of LOCK SIGNIFICANT EVENTS: Set-up and execution of HST PSS development testing. The purpose of this testing is to verify the PSS Simulator version xx (intentionally removed) can support Comm Module and SI FSW dumps. |
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