NASA Hubble Space Telescope Daily Report #3974
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT # 3974
PERIOD COVERED: UT October 25, 2005 (DOY 298)
OBSERVATIONS SCHEDULED
ACS/HRC 10114
Lyman_alpha FUV observations of the Sun in time and effects on planetary atmospheres
The chromospheric H I Ly_alpha 1215.6 feature is the dominant source of short-wave emission in the Sun and solar-type stars, contributing about 80-90% of the total FUV flux and 30-60% of the total flux between 1 and 1500 A. Also, this important chromospheric line is the major cooling channel for cool star atmospheres. Accurate Ly_alpha fluxes are the only missing element of our ongoing “Sun in Time” program. This program studies a sample of single G0-5 V stars with well-known physical properties that serve as proxies for the Sun {and solar-mass stars} over their main sequence lifetimes. One of the major goals of the program is the determination of the spectral irradiance of the early Sun. Our analyses indicate that the strong XUV emissions of the young Sun have played a crucial role in the developing planetary system. In particular, the expected strong Ly_alpha line flux may have greatly influenced the photoionization, photochemical evolution and possible erosion of planetary atmospheres, as well as played a role in the origin and development of life on Earth. The “Sun in Time” data can also be applied to investigate the atmospheric loss of exoplanets around solar-type stars resulting from XUV heating, which can eventually lead to the evaporation of “hot Jupiters”. We propose to determine accurate FUV and Ly-alpha fluxes and irradiances for 4 representative solar proxies with ages from 130 Myr to 6.7 Gyr. The proposed study is of capital importance in reconstructing the evolutionary histories of exoplanets already known and additional planets that missions such as COROT, Kepler, SIM, and Darwin/TPF will discover in the coming years.
ACS/SBC 10739
Internal Flat Field Stability
The stability of the CCD flat fields will be monitored using the calibration lamps and a sub-sample of the filter set. For the SBC imaging filters, differences in the low-frequency flat field structure with wavelength will be assessed. New high signal P-flats will be obtained for the SBC prisms.
ACS/WFC 10491
A Snapshot Survey of the most massive clusters of galaxies
We propose a snapshot survey of a sample of 124 high X-ray luminosity clusters in the redshift range 0.3-0.7. Similarly luminous clusters at these redshifts frequently exhibit strong gravitational lensing. The proposed observations will provide important constraints on the nature of the cluster mass distributions and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. We acknowledge the broad community interest in this sample and waive our data rights for these observations.
ACS/WFC 10493
A Survey for Supernovae in Massive High-Redshift Clusters
We propose to measure, to an unprecedented 30% accuracy, the SN-Ia rate in a sample of massive z=0.5-0.9 galaxy clusters. The SN-Ia rate is a poorly known observable, especially at high z, and in cluster environments. The SN rate and its redshift dependence can serve as powerful discrimiminants for a number of key issues in astrophysics and cosmology. Our observations will: 1. Put clear constraints on the characteristic SN-Ia “delay time, ” the typical time between the formation of a stellar population and the explosion of some of its members as SNe-Ia. Such constraints can exclude entire categories of SN-Ia progenitor models, since different models predict different delays. 2. Help resolve the question of the dominant source of the high metallicity in the intracluster medium {ICM} – SNe-Ia, or core-collapse SNe from an early stellar population with a top-heavy IMF, perhaps those population III stars responsible for the early re-ionization of the Universe. Since clusters are excellent laboratories for studying enrichment {they generally have a simple star-formation history, and matter cannot leave their deep potentials}, the results will be relevant for understanding metal enrichment in general, and the possible role of first generation stars in early Universal enrichment. 3. Reveal, via nuclear variability, the AGN fraction in clusters at this redshift, to be compared with the field AGN fraction. This will be valuable input for understanding black-hole demographics, AGN evolution, and ICM energetics. 4. Potentially discover intergalactic cluster SNe, which can trace the stripped stellar population at high z.
ACS/WFC 10496
Decelerating and Dustfree: Efficient Dark Energy Studies with Supernovae and Clusters
We propose a novel HST approach to obtain a dramatically more useful “dust free” Type Ia supernovae {SNe Ia} dataset than available with the previous GOODS searches. Moreover, this approach provides a strikingly more efficient search-and-follow-up that is primarily pre- scheduled. The resulting dark energy measurements do not share the major systematic uncertainty at these redshifts, that of the extinction correction with a prior. By targeting massive galaxy clusters at z > 1 we obtain a five-times higher efficiency in detection of Type Ia supernovae in ellipticals, providing a well-understood host galaxy environment. These same deep cluster images then also yield fundamental calibrations required for future weak lensing and Sunyaev-Zel’dovich measurements of dark energy, as well as an entire program of cluster studies. The data will make possible a factor of two improvement on supernova constraints on dark energy time variation, and much larger improvement in systematic uncertainty. They will provide both a cluster dataset and a SN Ia dataset that will be a longstanding scientific resource.
ACS/WFC/NIC3 10632
Searching for galaxies at z>6.5 in the Hubble Ultra Deep Field
We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the area of the original Hubble Ultra Deep Field NICMOS parallel fields and – through simultaneous parallel observations – deep NICMOS {F110W, F160W} imaging of the ACS UDF area. Matching the extreme imaging depth in the optical and near-IR bands will result in seven fields with sufficiently sensitive multiband data to detect the expected typical galaxies at z=7 and 8. Presently no such a field exist. Our combined optical and near-IR ultradeep fields will be in three areas separated by about 20 comoving Mpc at z=7. This will allow us to give a first assessment of the degree of cosmic variance. If reionization is a process extending over a large redshift interval and the luminosity function doesn’t evolve strongly beyond z=6, these data will allow us to identify of the order of a dozen galaxies at 6.5
FGS 10610
Astrometric Masses of Extrasolar Planets and Brown Dwarfs
We propose observations with HST/FGS to estimate the astrometric elements {perturbation orbit semi-major axis and inclination} of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information {McArthur et al. 2004}, allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.
FGS 10757
Monitoring FGS1r’s Interferometric Response as a Function of Spectral Color
This proposal obtains reference point source Transfer Functions {S-Curves} for FGS1r through the F583W filter and the F5ND attenuator at the center position of the FGS1r FOV for a variety of stars of different spectral types. These Transfer Functions are needed to support the analysis of GO science data for the study of close and wide binary star systems and for determining the angular size and shape of extended sources. This proposal observes stars that have been observed in previous cycles to monitor the long term evolution of the FGS1r S-curves. This proposal also {1} monitors the FGS1r Lateral Color response {using stars Latcol-A and Latcol-B}, {2} calibrates the “Pos/Trans” bias of a star’s position as determined from Transfer mode and Position mode observations, and {3} calibrates the shift of a star’s centroid when observed with F5ND relative to that when observed with F583W.
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.
WFPC2 10360
WFPC2 CYCLE 13 INTERNAL MONITOR
This calibration proposal is the Cycle 13 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 10745
WFPC2 CYCLE 14 INTERNAL MONITOR
This calibration proposal is the Cycle 14 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 {both gain 7 and gain 15 — to test stability of gains and bias levels}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. These also provide raw data for generating annual super-bias reference files for the calibration pipeline.
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
FGS
Gsacq 13 13
FGS Reacq 01 01
OBAD with Maneuver 28 28
SIGNIFICANT EVENTS: (None)
