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Daily 3873
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science DAILY REPORT # 3873 PERIOD COVERED: DOY 153 OBSERVATIONS SCHEDULED ACS/HRC 10431 A Search for Faint Companions of Altair We propose to use the innovative new technique of spectral deconvolution {Sparks & Ford 2002} to search for very faint companions, possibly extrasolar planets shining by reflected light, around Altair, the nearest bright, single star to the Sun. The technique offers a Poisson-limited detection capability that brings Jovian-class planets into the realm of feasibility for a select few stars. We turn the wavelength dependence of the coronagraphic PSF to advantage and use it to eliminate stray light from the host star. As part of the detection process, we obtain a spectrum over the wavelength range, 750 nm to 1 micron, with 9% resolution. The search will be orders of magnitude more sensitive than all previous efforts and should take us to within about an order of magnitude of the Jovian luminosity flux limit. ACS/HRC/WFC 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 10258 Tracing the Emergence of the Hubble Sequence Among the Most Luminous and Massive Galaxies There is mounting evidence that the redshift range 1 z 2 was an important era when massive galaxies assembled their stellar content and assumed their present-- day morphologies. Despite extensive HST imaging surveys, however, there is very little data in the optical rest frame {i.e., observed near--infrared} on the morphologies of the most luminous galaxies at these redshifts. We propose to image a carefully selected set of 20 of the most luminous, K--band selected GOODS galaxies at 1.3 z 2, using NICMOS camera 2. This offers diffraction-- limited, critically sampled imaging at 1.6 microns to ensure the best angular resolution for comparison to ACS. The galaxies are chosen to span a simple 4--fold parameter space of morphological and spectral type, in order to provide the most information about the variety of massive galaxy properties in this redshift range. We will investigate the emergence of large scale--length disks, stable spiral structure, mature bulges with red stellar populations, central bar structures, the incidence of disturbed morphology, the existence {or lack thereof} of blue ellipticals, and other questions that concern the evolution and maturation of the brightest, largest, and most massive ordinary galaxies in this critical redshift range. NIC3/WFPC2/ACS/WFC 10131 Determining the Origin of Virgo's Intracluster Stars Intracluster stars constitute about 20% of the total stellar population of a typical galaxy cluster, and their existence provides a vital clue for our understanding of cluster formation and evolution. However, to exploit their probative value, we need to know their origins: are they the remnants of dwarf galaxies, long since destroyed by the cluster potential, or have the stars been harassed from their parent galaxies at recent epochs? To answer this question, we propose to use the Wide-Field Channel of ACS to make an I, {V-I} color-magnitude diagram of Virgo's intracluster stars. From the position and morphology of the population's red giant branch, we will be able to determine the metallicity distribution function of the stars, and thereby determine their likely origin and ejection mechanisms. Only HST with the ACS has the sensitivity and resolution to perform this fundamental measurement. This program has two options. Option one uses conventional methods of cluster photometry and requires 37 orbits of exposure time. Option two involves a novel analysis technique, which promises to achieve most of the same science in two- thirds the time {23 orbits}. We describe this alternative method of analysis and demonstrate its use via simulations. 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. 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: (None) SCHEDULED SUCCESSFUL FAILURE TIMES FGS Gsacq 05 05 FGS Reacq 09 09 FHST Update 08 08 LOSS of LOCK SIGNIFICANT EVENTS: (None) |
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