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Daily 3661
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3661 PERIOD COVERED: DOYs 205-207 OBSERVATIONS SCHEDULED STIS/CCD/MA1 9841 Ultraviolet Observations of a Very Young Brown Dwarf We propose to obtain an ultraviolet spectrum of a 25 Jupiter mass, 10 million-year old brown dwarf in the TW Hya association. 2MASSW J1207334-393254 shows extremely strong H alpha emission, making it the brightest and closest member of a rare class of active young brown dwarfs.The UV observations will characterize the hot gas that is deduced to surround this brown dwarf. Very little about brown dwarf activity is understood, but X-ray, optical, and radio studies have shown that brown dwarf activity is quite different from cool star activity. Observations are needed to understand the source of the observed optical emission lines. The proposed observations will supplement existing optical and scheduled Chandra X-ray data. STIS/CCD 9839 Recombination Lines and Temperature Structure in Planetary Nebulae A high-spatial resolution study of recombination lines {RLs} in bright compact planetary nebulae {PNs} is proposed. Many PNs show a large discrepancy between abundances derived from O II RLs and those derived from [O III]. Others show little or no discrepancy. The PNs with small discrepancies are more compact and high surface brightness. This program seeks to understand why PNs show such differences by studying the RLs at high spatial resolution in the compact PNs NGC 6572 and NGC 6790, which show no discrepancy between O II and [O III], to compare with ground-based studies of the larger PNs NGC 6153 and NGC 6720. The goal is to determine if the distribution of RL emission in NGC 6572 and NGC 6790 is more consistent with radiative recombination than in NGC 6720, where the RL emission is more centrally peaked than [O III]. This will allow us to demonstrate whether or not it is the RLs that are preferentially enhanced in the nebulae with large discrepancies. The Cat's Eye nebula NGC 6543 will also be observed, to determine if the enhanced RL emission is connected to the presence of X-ray emitting gas, as might be expected if the enhanced RLs are a result of high temperature dielectronic recombination. NIC1 9833 T Dwarf Companions: Searching for the Coldest Brown Dwarfs Faint companions to known stars have historically led to the discovery of new classes of stellar and substellar objects. Because these discoveries are typically limited by the flux ratio of the components in the system, the intrinsically faintest companions are most effectively identified around the intrinsically faintest primaries. We propose to use NICMOS to image a sample of 22 of the coolest known {T-type} brown dwarfs in the Solar Neighborhood in order to search for fainter and cooler brown dwarf companions. The high spatial resolution of the NIC 1 detector enables us to distinguish binary systems with apparent separations greater than 0"08, or physical separations greater than 1.2 AU at the nominal distances of the objects in our sample. Furthermore, the substantial sensitivity of NICMOS imaging allows us to probe companion masses of 5-50 Jupiter masses and companion effective temperatures of 250-1300 K in a maximally efficient manner. Based on work to date, we expect that roughly 20% of the objects in our sample will be binary, and that one or two of these will likely harbor a significantly fainter secondary. Hence, we expect to find a companion cooler than any currently known brown dwarf, a potential prototype for the next spectral class. In addition, our investigation will add substantially to the sample of known binary brown dwarfs, allowing improved statistical analyses of the binary fraction, separation distribution, and mass ratio distribution of these systems, key quantities for probing brown dwarf formation. We will also identify optimal substellar systems for astrometric mass measurements, a critical check for theoretical models of brown dwarfs and extrasolar planets. WFPC2 9816 Proper motion kinematics in Galactic bulge/bar fields With this proposal we continue a successful programme to measure proper motions in fields in the galactic bulge. We are able to reach accuracies of ca 10km/s in transverse motion at a distance of 8kpc, for thousands of stars per WFPC2 field. In combination with VLT spectroscopic radial velocities and metallicity indices, we will be able to construct a full dynamical and stellar-population model for our Bulge. Previous fields in this programme were on the minor axis; the fields proposed here {using first epoch observations from 1995-1998 from the archive} lie in the first quadrant, on the near side of the Galactic bar. We also wish to establish first-epoch observations in the 4th quadrant, where no suitable data exist so far. ACS/HRC 9782 Measuring Black Hole Masses in Double Peaked Broad Lined AGNs To date there have been few black hole {BH} mass estimates for luminous broad line AGN, including those derived from reverberation mapping. In this context, objects with "double-peaked" broad lines are particularly important because the line emission is believed to arise in a relativistically rotating accretion disk. If this model is correct, then the BH mass can be determined directly from periodic variations in the line-profile shape. In two cases {Arp 102B and NGC 1097} such variations have been claimed. The goal of this proposal is to confront the relativistic disk model for the double-peaked Balmer lines with independent limits on the central masses for 5 of the nearest and brightest "double-peaked emitters" {NGC 1097, Arp 102B, Pictor A, 3C390.3, 3C332}, determined by using STIS long-slit spectroscopy to map the velocity field of circum-nuclear ionized gas. These observations will critically test the idea that the line emission in these objects comes from an accretion disk and thus provide unique insights into the physical processes operating in both the BLR and the "central engine". ACS/WFC 9744 HST Imaging of Gravitational Lenses Gravitational lenses offer unique opportunities to study cosmology, dark matter, galactic structure, galaxy evolution and quasar host galaxies. They are also the only sample of galaxies selected based on their mass rather than their luminosity or surface brightness. While gravitational lenses can be discovered with ground-based optical and radio observations, converting them into astrophysical tools requires HST. We will obtain ACS/WFC V and I images and NICMOS H images of 21 new lenses never observed by HST and NICMOS H images of 16 lenses never observed by HST in the IR. As in previous cycles, we request that the data be made public immediately. ACS/WFC 9727 Exploration of the SN Ia Hubble Diagram at z 1.2 In the spirit of a Treasury proposal, we propose to organize, and deliver to the astronomical community, non-proprietary follow-up observations of ~10 Type Ia supernovae at 1z1.7 that are expected to be discovered in a Cycle 12 Treasury proposal. Together with the currently available sample, this would provide a Hubble diagram with over 20 SNe Ia in this redshift range, where it is possible to test the current cosmological model in the epoch of deceleration: If z ~ 0.5 SNe Ia are fainter due to evolution rather than an accelerating expansion, they should continue to get fainter at even higher redshifts. This size sample will show trends and outliers, and permit a more rigorous treatment of the asymmetric amplification distribution from gravitational lensing. This is a key redshift range for the studies of dark energy that will be done with future surveys; this dataset will lay the ground-work for these studies by establishing the simple properties of the supernovae in this redshift range, including magnitudes, colors, and timescales. If considered more appropriate, this proposal could be treated as a part of a Treasury or Director's Discretionary program, since the data would be available to everybody immediately, and we would welcome others who would want to work with us on it. 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. ACS/HRC 10330 Coronagraphic search for disks around nearby stars We will use the coronagraphic and imaging modes of the High Resolution camera to study of the role of circumstellar disks in planetary system formation over timescales of ~1-1000 Myr. Our targets comprise pre Main-Sequence {MS} and MS stars, selected by infrared excess, and targets selected from SIRTF surveys. Some targets, like Beta Pictoris have debris disks that have been detected at optical or near-IR wavelengths, while others have disks inferred from mid-IR or ISO observations. We will obtain multicolor images of each target's circumstellar environment for the purpose of {1} detecting and characterizing disk morphologies over all scales {including warps and regions of enhanced or depleted density}, and {2} seeking evidence of embedded planets. Direct and occulted images will be recorded for studying the disks within 2 arcseconds of these targets; the coronagraph will be used to image the outer regions of the disks. Together with existing infrared observations, we will provide constraints on the sizes, distribution, and composition of dust grains. Unconfirmed disks will first be imaged in F606W, and if they exist we may later observe them in F435W and F814W. ACS/WFC/STIS/CCD 10263 SAINTS - Supernova 1987A Intensive Survey SAINTS is a program to observe SN 1987A, the brightest supernova in 383 years, as it transforms into supernova remnant {SNR} 1987A, the youngest supernova remnant. HST is the unique and perfect match in scale and in field for spatially-resolved observations of SN 1987A. Rapid changes are taking place in a violent encounter between the fastest-moving debris and the circumstellar ring. This one-time-only event, leading to suddenly appearing hotspots and new emission that can reveal previously hidden gas, is powered by shocks that can be studied simultaneously with HST and with Chandra to great advantage. Both the optical and X-ray flux from the ring are rising rapidly so prompt observations are needed in Cycle 13. Our previous observations reveal a remarkable reverse shock moving upstream through the expanding debris. The reverse shock provides a powerful tool for dissecting the radial structure of the vanished star. The debris from the explosion itself, still excited by radioactivity, is now well resolved by ACS and seen to be aspherical, providing direct clues to the mechanism of the explosion. Many questions about SN 1987A remain unanswered. SAINTS is a comprehensive attempt to use HST to establish the facts of SN 1987A, help to answer interesting questions, and to observe the birth of SNR 1987A. ACS/HRC 10255 A Never Before Explored Phase Space: Resolving Close White Dwarf / Red Dwarf Binaries We propose an ACS Snapshot imaging survey to resolve a well-defined sample of highly probable white dwarf plus red dwarf close binaries. These candidates were selected from a search for white dwarfs with infrared excess from the 2MASS database. They represent unresolved systems {separations less than approximately 2" in the 2MASS images} and are distributed over the whole sky. Our HST+ACS observations will be sensitive to a separation range {1-20 AU} never before probed by any means. The proposed study will be the first empirical test of binary star parameters in the post-AGB phase, and cannot be accomplished from the ground. By resolving as few as 20 of our ~100 targets with HST, we will be able to characterize the distribution of orbital semi-major axes and secondary star masses. ACS/HRC 10240 Stars versus Gas: A Direct Comparison of Black Hole Mass Measurement Techniques Hundreds of orbits of HST time have been devoted to measurements of the masses of black holes in the centers of nearby galaxies, using the kinematics of either stars or ionized gas disks. Gas-dynamical measurements are far simpler in terms of observations and analysis, but are subject to systematic uncertainties since the gas disks may not be rotating at the local circular velocity. Cross-checks between the two methods are critically important, but to date there has not been any direct test of the two methods to determine whether they would give consistent results for the same galaxy. We propose to compare stellar-dynamical and gas-dynamical measurements of the black hole masses in two S0 galaxies, NGC 3245 and NGC 1380, that we have selected as excellent candidates for both techniques. This direct comparison will help to clarify the amount of intrinsic scatter in the black hole mass vs. stellar velocity dispersion correlation and improve our understanding of local black hole demographics. For NGC 3245 we have already performed the gas-dynamical measurement. NIC2 10228 Multi-color HST imaging of the GJ 803 debris disk We propose to conduct a comprehensive high angular resolution study of the newly discovered debris disk around GJ 803. This nearby, young star has an estimated age of 8-20 Myr, a critical epoch in disk evolution and planet formation. By virtue of its proximity {10 pc} and nearly edge-on orientation, GJ 803's disk has an exceptional surface brightness and angular size relative to other disks resolved in scattered light thus far. Hence, this system offers an exciting new opportunity to study debris disks. Our proposed ACS and NICMOS imaging will elucidate the disk morphology, ascertain the grain properties as a function of radius, and search for fine dynamical structure indicative of the presence of planets. ACS WFC and NICMOS coronagraphic imaging will explore the inner disk, which includes the ~17 AU inner disk hole inferred from the star's spectral energy distribution. Complementary ACS WFC imaging will probe the outer disk {70 AU}; at such large distances around GJ 803, dust evolutionary timescales are longer than the stellar age, and hence we can study the composition of primordial circumstellar material. The combined dataset will provide the most comprehensive study to date of a debris disk from ~7 AU to ~200 AU radius. 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. STIS/CCD 10222 The Next Generation Spectral Library We propose to complete our snapshot program to produce a Next Generation Spectral Library of 600 stars for use in modeling the integrated light of galaxies and clusters. This program is using the low dispersion UV and optical gratings of STIS. The library will be roughly equally divided among four metallicities, very low {[Fe/H] -1.5}, low {-1.5 [Fe/H] -0.5}, near-solar {-0.3 [Fe/H] 0.1}, and super-solar {[Fe/H] 0.2}, well-sampling the entire HR-diagram in each bin. Such a library will surpass all extant compilations and have lasting archival value, well into the Next Generation Space Telescope era. Because of the universal utility and community-broad nature of this venture, we waive the entire proprietary period. ACS/WFC 10181 ACS/NICMOS Imaging of Bright Lyman Break Galaxy Candidates from SDSS The recent surprising discovery of six unusually bright {r~20 mag} Lyman break galaxy {LBG} candidates with z=2.45-2.80 in the Sloan Digital Sky Survey {SDSS} raises a number of questions that only HST can address. Specifically, what is the true nature of these objects, and what role if any is played by gravitational lensing? We propose to use the superior resolution and sensitivity of ACS and NICMOS to obtain deep images of these objects and their environments. Compared to SDSS images, HST will allow us to determine their morphologies {extended, point-source, or lensed}, the appearance of their environments {rich or poor}, and to detect any faint foreground groups or clusters that might be responsible for lensing these objects. All outcomes would be intriguing. If the objects are lensed, it increases from 1 {MS1512-cB58} to 7 the number of normal LBGs bright enough to study individually. If they are instead unlensed point sources, they will represent a new class of previously unidentified absorption-line quasars. Finally, if they are unlensed and extended star-forming galaxies, they are at least 4mag brighter than L_* LBGs, thus making them the most luminous star-forming objects yet seen, representing a heretofore unknown extreme population of objects. NIC2 10176 Coronagraphic Survey for Giant Planets Around Nearby Young Stars A systematic imaging search for extra-solar Jovian planets is now possible thanks to recent progress in identifying "young stars near Earth". For most of the proposed young {~ 30 Myrs} and nearby {~ 60 pc} targets, we can detect a few Jupiter-mass planets as close as a few tens of AUs from the primary stars. This represents the first time that potential analogs of our solar system - that is planetary systems with giant planets having semi-major axes comparable to those of the four giant planets of the Solar System - come within the grasp of existing instrumentation. Our proposed targets have not been observed for planets with the Hubble Space Telescope previously. Considering the very successful earlier NICMOS observations of low mass brown dwarfs and planetary disks among members of the TW Hydrae Association, a fair fraction of our targets should also turn out to posses low mass brown dwarfs, giant planets, or dusty planetary disks because our targets are similar to {or even better than} the TW Hydrae stars in terms of youth and proximity to Earth. Should HST time be awarded and planetary mass candidates be found, proper motion follow-up of candidate planets will be done with ground-based AOs. ACS/WFC 10158 ACS Observations of the Gravitational Lens B1608+656: Characterizing the Einstein Ring We request time to obtain ACS deep images of the B1608+656 gravitational lens system to fully characterize its enclosing Einstein ring with high signal-to-noise ratio {SNR}. These data will allow us to determine the gravitational potential of the lens, locally, to several percent accuracy and, combined with the three independent time delays, measure H_0 to much better than 10% precision. For this goal, we have developed powerful new lens modeling codes that make use of the full brightness distribution of the Einstein ring in lens systems. The B1608+656 system is ideal for our new code. It has precisely measured time delays, a well-determined stellar velocity dispersion, and an Einstein ring that is not dominated by the lensed nuclear emission of the background source. When combined with high-SNR images of Einstein rings, the new modeling codes provide qualitatively different and much improved analysis of the ring emission than was previously possible. The proposed ACS observations will reach the SNR at which the new modeling code can be fully exploited {SNR=5 per pixel}. Our simulations show that these new data will allow us to reduce the total uncertainties in H_0 derived from the system by at least a factor of two, to the 5-7% level for this system. ACS/WFC 10146 Solving the problem of the White Dwarf Cooling Sequence End in M4: an efficient approach The end of the white dwarf {WD} cooling sequence {WDCS} has never been observed, despite the importance that it has in providing an age estimate of old stellar systems, independent from the standard method of the main sequence turn off. The best targets for this investigation are the closest stellar clusters, and, among them, globular clusters are the most interesting ones. Being the oldest stellar aggregates, they allow to probe the advanced WD cooling phases, and the independent age estimate coming from the end of their WDCS has an important cosmological impact. M4 is the best target for this investigation. Despite huge observational efforts, we still miss the end of its WDCS. The ACS camera offers a unique opportunity to identify it. Coupled with already existing observations, we here prove that we can finally reach it with only 10 HST orbits. This is probably the last opportunity we have for a large number of years. The data we are requesting here, will also be used to complete other two programs of great astrophysical impact: the observational detection of the main sequence hydrogen burning limit, and the measurement of the geometrical distance of M4. WFPC2 10071 WFPC2 CYCLE 12 Supplemental Darks Part 3/3 This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels. ACS/HRC/WFC 10061 CCD Daily Monitor This program consists of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. This programme will be executed once a day for the entire lifetime of ACS. STIS/CCD 10020 CCD Bias Monitor - Part 2 Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns. STIS/CCD 10018 CCD Dark Monitor-Part 2 Monitor the darks for the STIS CCD. WFPC2/ACS/HRC/WFC 10013 Focus Monitor The focus of HST is measured from WFPC2/PC and ACS/HRC images of stars. Multiple exposures are taken in parallel over an orbit to determine the influence of breathing on the derived mean focus. Observations are taken of clusters with suitable orientations to ensure stars appear in all fields. 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: 1115-0 CCC IPCONFIG Connections @ 205/14:11z 1252-0 Change Limits MAMA2 Threshold Voltage @ 205/22:10z 1246-0 Battery 5 Capacity Test Ground Limits @ 206/20:11z 1246-0 Battery 5 Capacity Test Ground Limits @ 206/22:11z SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 32 32 FGS REacq 17 17 FHST Update 49 49 LOSS of LOCK SIGNIFICANT EVENTS: None |
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