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DAILY REPORT #3907
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT #3907 PERIOD COVERED: UT July 21, 2005 (DOY 202) OBSERVATIONS SCHEDULED ACS/HRC/NIC3 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/WFC 10411 Catching optical emission from the first discovered double-pulsar system: J0737-3039 This proposal is aimed to detect optical emission from one of the most intriguing astronomical object ever found in the sky: the newly discovered binary system harbouring two pulsar {PSR J0737-3039A and PSR J0737-3039B}. This is the first double- pulsar system ever detected {Burgay et al. 2003; Lyne et al. 2004} and it provides a wonderful laboratory for the study of relativistic gravity and gravitational radiation. Moreover, for the first time, it offers the opportunity to probe the magnetosphere and the local environment of a neutron star. There is indeed evidence of strong interactions between the energy released by one pulsar and the magnetosphere of the other. Our team is now carrying out a multi-wavelength project to understand the nature of the occurring interactions and the energy budget of the system. In particular, while radio observations will continue to survey the object, X-ray observations with Chandra have been already allocated. Here we ask for deep ACS-HR observations to catch the optical emission from the system. These observations will firstly estimate the optical nonthermal flux, and, once combined with radio and X-ray fluxes, will give us unique insights into the physics of the relativistic wind interactions within the system. ACS/HRC/WFC/NIC2 10399 Accurate and Robust Calibration of the Extragalactic Distance Scale with the Maser Galaxy NGC4258 II The extragalactic distance scale {EDS} is defined by a comparison of Cepheid Period- Luminosity {PL} relations for nearby galaxies and the LMC, whose uncertain distance is thereby the SOLE anchor. Studies of masers orbiting the central black hole in NGC4258 have provided the most accurate extragalactic distance ever {7.2+/-0.5 Mpc}, and new radio data and analysis techniques will reduce the uncertainty to 3.5% {0.07 mag} by 2005. Since this distance is well determined and based on geometric arguments, NGC4258 can provide a much needed new anchor for the EDS. Ultimately, the combination of an independent measurement of H0 and measurements of CMB fluctuations {e.g., WMAP} can be used to directly constrain cosmological parameters including the equation of state of dark energy. In our Cycle 12 proposal, we defined a program spanning two cycles. The Cycle 12 portion was accepted. We have acquired WFC images and are constructing well sampled PL relations in 3 colors {BVI}. The purpose of the Cycle 13 observations is to address systematic sources of error and is crucial for the success of the entire program. To disentangle the effects of reddening and metallicity, and to characterize the effects of blending, we require 50 orbits to obtain H-band photometry {NICMOS/NIC2} and high resolution images {ACS/HRC}. ACS/WFC/WFPC2 10394 Deep imaging of newly discovered globular clusters in the outer halo of M31 Globular clusters {GCs} are fossil relics with which we can investigate the processes of galaxy formation and growth. We have recently discovered a sample of GCs, as part of a very wide area CCD survey of M31. These clusters span a range in projected galactocentric distance of 20 - 80 kpc, more than double the radii of the previous most remote known GC. Here we apply for deep ACS images of 13 GCs, which will allow us to study their stellar populations, line-of-sight distances and structural parameters. These will be used to: a} Investigate the merger history of M31, through an examination of variations in the RGB and HB morphologies, particularly to obtain metallicities and check for the presence of any second parameter effect in the HB. d} Determine, in conjuction with ground-based spectroscopy, the dynamical mass of M31 at large radius, providing a direct probe of the mass distribution of its dark halo. 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. 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: 1357-0 HST486 Full EEPROM Memory Dump @ 202/16:35z 1356-0 HST486 Full RAM Memory Dump @ 202/22:56z SCHEDULED SUCCESSFUL FGS Gsacq 06 06 FGS Reacq 11 11 FHST Update 07 07 |
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