#1
|
|||
|
|||
Daily 3922
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3922 PERIOD COVERED: UT August 11, 2005 (DOY 223) OBSERVATIONS SCHEDULED ACS/HRC 10557 Probing Asteroid Families for Evidence of Ultraviolet Space Weathering Effects We propose six HST orbits to obtain UV reflectance spectra covering 200-460 nm of two Vesta asteroid family members, asteroid 832 Karin, and two Karin family members. These observations extend work done under a Cycle 13 AR grant, where we analyzed all of the existing IUE and HST S-class asteroids in the MAST database to investigate the effects of space weathering at UV wavelengths. Our hypothesis is that the manifestation of space weathering at UV wavelengths is a spectral bluing, in contrast with a spectral reddening at visible-NIR wavelengths, and that UV wavelengths can be more sensitive to relatively small amounts of weathering than longer wavelengths. The proposed observations will address two objectives: {1} Measure the UV-visible spectra of 832 Karin and two members of the young Karin family {absolute age of 5.8 My}, in order to determine whether intermediate space weathering is observable in objects likely pristine when they originated from the interior of Karin's pa rent body. {2} Measure the UV-visible spectra of two members of the Vesta family to compare with our analysis of IUE Vesta spectra. These observations will probe Vesta's interior, and test our hypothesis by contrasting the apparent amount of alteration on the surfaces of Vestoids with excavated material on Vesta. ACS/HRC/WFC 10370 CCD Hot Pixel Annealing Hot pixel annealing will continue to be performed once every 4 weeks. The CCD TECs will be turned off and heaters will be activated to bring the detector temperatures to about +20C. This state will be held for approximately 12 hours, after which the heaters are turned off, the TECs turned on, and the CCDs returned to normal operating condition. To assess the effectiveness of the annealing, a bias and four dark images will be taken before and after the annealing procedure for both WFC and HRC. The HRC darks are taken in parallel with the WFC darks. The charge transfer efficiency {CTE} of the ACS CCD detectors declines as damage due to on-orbit radiation exposure accumulates. This degradation has been closely monitored at regular intervals, because it is likely to determine the useful lifetime of the CCDs. We will now combine the annealling activity with the charge transfer efficiency monitoring and also merge into the routine dark image collection. To this end, the CTE monitoring exposures have been moved into this proposal . All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} and First Pixel Response {FPR} data will be obtained over a range of signal levels for both the Wide Field Channel {WFC}, and the High Resolution Channel {HRC}. ACS/HRC/WFC 10389 ACS CCDs daily monitor - Cycle 13 - Part 2 This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This program will be for the entire lifetime of ACS. ACS/SBC 10502 ACS Imaging of the Uranus Aurora and Hydrogen Corona ACS SBC UV observations of Uranus are proposed with dual purposes that can be achieved with a single set of observations. First, we propose to observe the very unusual auroral of Uranus for the first time since IUE and Voyager in the 1980's. The Uranus aurora are centered on the magnetic poles, corresponding to the 60 deg. tilted magnetic moment, closer to the equator than the rotational poles. The brighter auroral emission appears around the weaker magnetic pole. The auroral emissions are highly variable, as recorded with IUE, and the rotational phase of Uranus is not known. The observations will therefore cover the extent of a Uranus rotation {17.29 hours}, and will be repeated one-half solar rotation later to allow for variations in the solar wind at Uranus. The high sensitivity of the ACS SBC at long wavelengths will increase the sensitivity to auroral H2 emissions, and observations in cycle 14 near solar minimum will limit the sky background and reflected solar emissions from the Uranus disc. Secondly, these images will measure the extended hydrogen corona of Uranus, first seen by the Voyager 2 UVS. We propose to model the distribution of the hydrogen corona to determine the source processes in the Uranus upper atmosphere, by comparison with model runs from an exospheric code. ACS/WFC/NIC3 10405 Probing the establishment of galaxy morphologies in the best-studied high-redshift structure We propose deep ACS I-band imaging of arguably the best-studied high-redshift proto-cluster environment, a high-contrast structure in the SSA22 field at z=3.1. Our on-going study of this region has identified over 400 probable members of this structure across a 16-arcmin-square field, selected through narrow-band Lyman-alpha emission, Lyman-break photometric criteria and far-infrared/radio emission. Our proposed high-resolution imaging of galaxies in the z=3.1 structure and in the nearby field, will provide morphological information on galaxies over nearly two-orders of magnitude in local density at this early epoch. This will allow us for the first time to test whether galaxy morphology is defined at the formation of a galaxy or reflects processes acting on it during its lifetime. ACS/WFC/NIC3/WFPC2 10530 Probing Evolution And Reionization Spectroscopically {PEARS} While imaging with HST has gone deep enough to probe the highest redshifts, e.g. the GOODS survey and the Ultra Deep Field, spectroscopic identifications have not kept up. We propose an ACS grism survey to get slitless spectra of all sources in a wide survey region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field in the HUDF reaching sources up to z =28 magnitude. The PEARS survey will: {1} Find and spectrocopically confirm all galaxies between z=4-7. {2} Probe the reionization epoch by robustly determining the luminosity function of galaxies and low luminosity AGNs at z = 4 - 6. With known redshifts, we can get a local measure of star formation and ionization rate in case reionization is inhomogeneous. {3} Study galaxy formation and evolution by finding galaxies in a contiguous redshift range between 4 z 7, and black hole evolution through a census of low-luminosity AGNs. {4} Get a robust census of galaxies with old stellar populations at 1 z 2.5, invaluable for checking consistency with heirarchical models of galaxy formation. Fitting these galaxies' spectra will yield age and metallicity estimates. {5} Study star-formation and galaxy assembly at its peak at 1 z 2 by identifying emission lines in star-forming galaxies, old populations showing the 4000A break, and any combination of the two. {6} Constrain faint white dwarfs in the Galactic halo and thus measure their contribution to the dark matter halo. {7} Derive spectro-photometric redshifts by using the grism spectra along with broadband data. This will be the deepest unbiased spectroscopy yet, and will enhance the value of the multiwavelength data in UDF and the GOODS fields to the astronomical community. To this end we will deliver reduced spectra to the HST archives. FGS 10478 Dynamical Masses and Radii of Four White Dwarf Stars The cool white dwarf stars WD1639+153 and WD1818+126 were recently resolved by HST FGS1r to be double degenerate binary systems with projected separations of 112 mas and 174 mas respectively. At a distance of less than 50 pc they may both have periods shorter than about 20 years, making them ideal candidates for follow up studies for dynamical mass determinations. This will increase the number of white dwarfs with dynamical mass measurements from the current 4 up to 8. Continued observations of these white dwarfs along with nearby field stars with the FGS will accuractely determine the orbital elements and parallax of each system. The mass and radius of all four white dwarfs can be determined to an unprecedented 1%, making it possible to test and calibrate the theoretical white dwarf mass radius relation at the cool end of the cooling curve for the DA and DC subclasses. Since the components of the binary are coeval, once the mass and radius, and hence the cooling age of each star is known, it will be possible to estimate the relation between the initial mass and final mass for all four white dwarfs. We are requesting a total of 4 HST orbits per year for the next three cycles to initiate the process that will result in a determination of the mass and radius of the four white dwarfs. NIC1/NIC2/NIC3 10721 NICMOS dark current tests for newly implemented SPARS sequences On June 12, 2005, 4 new NICMOS multiaccum sequences {SPARS4, SPARS16, SPARS32, SPARS128} were implemented. The purpose of this observation is to measure the dark currents for these new multiaccum sequences for all three NICMOS detectors. 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 10510 Morphology of massive early-type galaxies at z1.2: constraining galaxy formation models We ask for NICMOS-NIC2 H-band imaging of a sample of 10 massive early-type galaxies spectroscopically identified at 1.2z1.7. Our aim is to look for possible relics of merging events of their formation/evolution in their morphology. The requested observations, sampling their rest- frame at lambda6500A, would map the mass distribution of the bulk of their stellar content. The targets have been revealed by our group on the basis of near-IR spectroscopy obtained in the framework of a spectroscopic survey of a complete sample of bright EROs {Ks18.5}. Optical and near-IR photometry is available for all the targets, and low resolution near-IR spectra have allowed their identification and redshift measurement. Spectroscopic and photometric data in our hands show that they have already assembled stellar masses greater than 3 10^11 solar masses, and that the mean age of their stellar population is estimated older than 2-3 Gyr for 6 of them and about 1 Gyr for the other 4 galaxies. Thus, they are among the most luminous and massive evolved galaxies detected so far at z1. Other data are needed to infer how they have assembled such high stellar masses, i.e. to trace back their evolution. The requested observations would allow us to reveal signs of past interaction/merger event. A smooth r^{1/m} profile, coupled with no other signs of interaction/merger {disturbed morphology}, would place the possible merger event of formation 1-2 Gyr before their redshift z pprox 1.5, i.e. at z 2-3. On the other hand, if signs of recent merger events will be found, the last merger event forming the local massive spheroids will be constrained at 1.5 z 2. Thus, the requested HST observations will allow for the first time to see how massive early-type galaxies at z pprox 1.5 look like, constraining in any case the redshift of the possible merging event of their formation. WFPC2 10534 Active Atmospheres 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; 8680: Hammel, Rages, Lockwood, and Marley; 8634: Rages, Hammel, Lockwood, Marley, and McKay; and 10170: Rages, Hammel, Lockwood, and Marley} 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 Telesccope 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.) HSTARS: (None) COMPLETED OPS REQUEST: 17495-0 - Null Genslew for Proposal 10431-0 - Slot#8 @ 223/1915z 17496-0 - Null Genslews for Proposal 10431-0 - Slot#9,10,11,14 @ 223/1916z SCHEDULED SUCCESSFUL FGS Gsacq 12 12 FGS Reacq 5 5 FHST Update 18 18 LOSS of LOCK COMPLETED OPS NOTES: (None) |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
BILLY MEIER RIGHT ON TARGET- Extraterrestrials - UFOs - Space - Mt. Everest | Ed Conrad | Astronomy Misc | 2 | August 4th 05 11:43 PM |
Ed Conrad's NEW Letter to Prof. Michael Behe | Ed Conrad | Astronomy Misc | 0 | June 21st 05 10:50 AM |
MYSTERIOUS ARTIFACTS, FOSSILS - Exhibit Now in Berlin -- Smallest Woman (5 in. or 14 cm) - Petrified Human Bones Found in Coal Seams & MORE | Ed Conrad | Astronomy Misc | 0 | June 9th 05 01:00 AM |
PENNY PINCHER -- The Buck Stops Here. | Ed Conrad | Astronomy Misc | 0 | June 7th 05 11:26 PM |
EVOLUTION DEAD AT AGE 126 -- R.I.P. | Ed Conrad | Astronomy Misc | 4 | August 21st 04 12:01 AM |