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Daily 3869
The Next Daily Report will be issued on May 31
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science DAILY REPORT # 3869 PERIOD COVERED: DOY 146 OBSERVATIONS SCHEDULED ACS/HRC 10145 Physical parameters of the upper atmosphere of the extrasolar planet HD209458b Every 3.5 days, the transits of the gaseous planet orbiting HD209458 offer the unique opportunity to investigate the spectral features of an extra-solar planetary atmosphere. Using HST, we first discovered the extended upper atmosphere of HD209458b through the detection of a 15% HI Lyman alpha absorption. We concluded that the hydrogen must be escaping the planet with a lower limit rate of 10^10 g/s {Vidal-Madjar et al. 2003}. Additional observations, subsequently allowed to detect OI and CII in the upper atmosphere implying that this atmosphere is hydrodynamically escaping {in "blow off", Vidal-Madjar et al. 2004}. Here we propose to further study this upper atmosphere to better constrain the "blow off" state by directly estimating the physical conditions and the flow characteristics. In particular we will determine the temperature and density at the base of the upper atmosphere {the thermosphere}, and the density distribution and ionization state just below that level. Comparison between the optical and ultraviolet occultation light curves will provide useful information on the molecular/haze content of the lower atmosphere. The observation of six HD209458b transits with HRC and SBC settings will allow the detection of many lines adressing these issues. The proposed observations will give us for the first time a detailed probe of the atmosphere of an "evaporating" extra-solar planet.With species as abundant as FeII or MgII, the damping wings in the strongest lines will start to form at levels around 1.9% absorption. Due to either the strength of the MgII doublet lines around 280 nm or the packing of FeII lines, strong absorptions arising from the accumulated damping wings should show up clearly in FeII and MgII. All these signatures should be easily detected even with the 40 to 100 Angstrom resolution of the PR200L prism in these spectral regions. In addition to these goals, any signature of molecules {e.g CO below 154 nm}, dust or haze should also show up as broad band absorption in both PR110L and PR200L settings. The estimate of the planet radius at different wavelengths in the UV would become possible for all efficient absorbers in this spectral range. The achievement of 0.1% precision in the occultation curves thus provides sensitivity high enough to potentially lead to important discoveries. ACS/WFC 10412 The host galaxies of dust-reddened quasars We have used the 2MASS near-infrared and FIRST radio surveys, together with the Palomar Observatory Sky Survey plates to select a sample of dust-reddened, radio- intermediate quasars. We wish to use ACS to study the host galaxies of these quasars. The dust reddening of the quasars makes it possible to study the hosts at rest-frame optical-UV wavelengths much more easily than the hosts of normal quasars of similar bolometric luminosity. Our study will compare the hosts of our dust-reddened quasars to those of normal quasars from the HST archive to test the hypothesis that dust-reddened quasars are young objects, whose hosts still show morphological evidence of recent merger events which triggered the quasar. ACS/WFC/NIC3 10195 Probing the Surroundings of a Highly Luminous Redshift 6.5 Galaxy We propose deep images of a recently discovered galaxy at z=6.535, which is among the most luminous Lyman-alpha emitting galaxies known at high redshift. The brightness and rarity of this source imply that it is associated with a high peak in the matter density distribution. {It is the brightest Lyman alpha source in 2e5 comoving Mpc3, with a luminosity of 6 L*.} Further objects in this peak are expected to be visible with HST's sensitivity. The Lyman alpha line has a large rest frame equivalent width, with a lower bound 100 Angstroms. Such a large equivalent width would be impossible for objects embedded in neutral gas, and instead requires either that {a} the universe was reionized before z=6.5 or {b} the galaxy resides in a local ionized bubble, in which case an additional contribution to the ionizing photon budget from presently undetected neighbors is required. With 19 orbits of ACS and NICMOS imaging, we will measure this object's morphology and spectral energy distribution, thus searching for either active nuclei or old stellar populations. We will also search for possible neighbors, which could establish the first known galaxy group at z6, and may provide sufficient ionizing flux to allow the escape of the observed Lyman alpha photons in a neutral universe. If neighbors are not found, it will lead to an upper bound on the neutral fraction in the general IGM at z=6.5. FGS 10432 Precise Distances to Nearby Planetary Nebulae We propose to carry out astrometry with the FGS to obtain accurate and precise distances to four nearby planetary nebulae. In 1992, Cahn et al. noted that ``The distances to Galactic planetary nebulae remain a serious, if not THE most serious, problem in the field, despite decades of study.'' Twelve years later, the same statement still applies. Because the distances to planetary nebulae are so uncertain, our understanding of their masses, luminosities, scale height, birth rate, and evolutionary state is severely limited. To help remedy this problem, HST astrometry can guarantee parallaxes with half the error of any other available approach. These data, when combined with parallax measurements from the USNO, will improve distance measurements by more than a factor of two, producing more accurate distances with uncertainties that are of the order of ~6%. Lastly, most planetary nebula distance scales in the literature are statistical. They require several anchor points of known distance in order to calibrate their zero point. Our program will provide "gold standard" anchor points by the end of 2006, a decade before any anticipated results from future space astrometry missions. NIC2 10169 Star Formation in Luminous Infrared Galaxies: giant HII Regions and Super Star Clusters Luminous Infrared Galaxies {LIRGs, LIR = 10^11-10^12Lsol} and Ultraluminous Infrared Galaxies {LIR10^12Lsol} account for approximately 75% of all the galaxies detected in the mid-infrared in the redshift range z=0-1.5. In the local universe it is found that LIRGs are predominantly powered by intense star formation {SF}. However, the physical conditions and processes governing such dramatic activity over scales of tens to a few hundred parsecs are poorly known. In the last decade HST has been playing a significant role, mainly with the discovery of super star clusters {SSCs}, and more recently, giant HII regions. Based on observations of a few LIRGs, we found that these giant HII regions and associated SSCs appear to be more common in LIRGs than in normal galaxies, and may dominate the star formation activity in LIRGs. A larger sample is required to address fundamental questions. We propose an HST/NICMOS targeted campaign of a volume limited sample {v5200km/s} of 24 LIRGs. This proposal will probe the role of giant HII regions in the overall energetics of the current star formation, their relation to SSCs, and the dependence of star formation properties on other parameters of LIRGs. Such detailed knowledge of the SF properties of LIRGs in the local universe is essential for understanding galaxies at high redshift. NICMOS 8790 NICMOS Post-SAA calibration - CR Persistence Part 1. 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. S/C 10700 Guide Star Test for the Deep Impact Encounter This proposal is to perform guide star tests on the critical HST science visits circum- encounter of the Deep Impact mission with comet 9P/Tempel 1. WFPC2/ACS/WFC 10397 The Ghosts of Galaxies: Tidal Debris and the Formation of Clusters Intergalactic stellar populations and tidal debris are now recognized as important components of galaxy clusters. This project examines the interrelated processes of galaxy destruction, recycling of tidal debris, and creation of dwarf galaxies and intergalactic star clusters, all of which are part of the grand scheme of cluster formation. We propose deep multicolor imaging of two examples of newly created tidal debris, the spectacular plumes in the Centaurus and Coma clusters. The Centaurus observations will extend our earlier work, which demonstrated the existence of tidal debris dwarf galaxies and star cluster in the body of the Centaurus plume. Deep ACS/WFC observations can determine rough ages and cluster membership, better characterizing the new debris. The Coma observations will reproduce this work for a second plume feature, in the quintessential rich cluster of galaxies. Parallel WFPC2 observations will investigate the central intracluster spaces at the bottom of the each cluster's potential, where older debris is thickest. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 9834 - The GSacq(2,1,2) scheduled during ZOE at 146/08:51:31 -08:59:33 failed to RGA control at AOS 146/09:00:27 (TDW). Three 486 ESB messages A0E(hex) were also observed at AOS when telemetry was reacquired, indicating FGS Sequential Attitude update failed because roll error was too large to correct. Prior FM Updates at 146/08:35:03, 146/08:37:48 showed good attitude error vector. COMPLETED OPS REQUEST: (None) COMPLETED OPS NOTES: (None) SCHEDULED SUCCESSFUL FAILURE TIMES FGS Gsacq 05 04 Hstar # 9834 FGS Reacq 10 07 Hstar # 9834 FHST Update 09 09 LOSS of LOCK SIGNIFICANT EVENTS: (None) |
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