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Daily Report #4518
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT***** # 4518 PERIOD COVERED: UT January 02, 2008 (DOY 002) OBSERVATIONS SCHEDULED ACS/SBC 11145 Probing the Planet Forming Region of T Tauri Stars in Chamaeleon By studying the inner, planet-forming regions of circumstellar disks around low-mass pre- main sequence stars we can refine theories of giant planet formation and develop timescales for the evolution of disks and their planets. Spitzer infrared observations of T Tauri stars in the Chamaeleon star-forming region have given us an unprecedented look at dust evolution in young objects. However, despite this ground breaking progress in studying the dust in young disks, the gas properties of the inner disk remain essentially unknown. Using ACS on HST, we propose to measure the H_2 emission originating in the innermost disk regions of classical T Tauri stars in different stages of evolution with the objective of revealing the timescales of gas dissipation and its relationship to dust evolution. This proposal is part of a comprehensive effort with approved programs on Spitzer, Gemini, and Magellan that aim to characterize the state of gas and dust in disks where planets may already have formed. ACS/SBC 11309 Chemical Composition of an Exo-Neptune The recent discovery that the Neptune-like exoplanet GJ 436 b transits its host star has presented us the first chance to observationally study ice giant formation beyond our solar system {Gillon et al. 2007}. Using Directors Discretionary time, we propose to obtain a high-precision light curve of the GJ 436 b transit with the FGS in order to improve the current radius determination for this planet. Measuring a precise radius for GJ 436 b will allow us to ascertain whether the planet has a pure water vapor or H/He envelope like Uranus and Neptune. Knowing this will constrain its formation and evolution and help place our own solar system ice giants in a broader context. Additionally, a precise radius for GJ 436 b will be a necessity for interpreting the certain follow-up observations of this unique system. FGS 11212 Filling the Period Gap for Massive Binaries The current census of binaries among the massive O-type stars is seriously incomplete for systems in the period range from years to millennia because the radial velocity variations are too small and the angular separations too close for easy detection. Here we propose to discover binaries in this observational gap through a Faint Guidance Sensor SNAP survey of relatively bright targets listed in the Galactic O Star Catalog. Our primary goal is to determine the binary frequency among those in the cluster/association, field, and runaway groups. The results will help us assess the role of binaries in massive star formation and in the processes that lead to the ejection of massive stars from their natal clusters. The program will also lead to the identification of new, close binaries that will be targets of long term spectroscopic and high angular resolution observations to determine their masses and distances. The results will also be important for the interpretation of the spectra of suspected and newly identified binary and multiple systems. FGS 11213 Distances to Eclipsing M Dwarf Binaries We propose HST FGS observations to measure accurate distances of 5 nearby M dwarf eclipsing binary systems, from which model-independent luminosities can be calculated. These objects have either poor or no existing parallax measurements. FGS parallax determinations for these systems, with their existing dynamic masses determined to better than 0.5%, would serve as model-independent anchor points for the low-mass end of the mass-luminosity diagram. NIC1/NIC2/NIC3 8794 NICMOS Post-SAA calibration - CR Persistence Part 5 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 DARKs. 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 11166 The Mass-dependent Evolution of the Black Hole-Bulge Relations In the local universe, the masses of giant black holes are correlated with the luminosities, masses and velocity dispersions of their host galaxy bulges. This indicates a surprisingly close connection between the evolution of galactic nuclei (on parsec scales) and of stars on kpc scales. A key observational test of proposed explanations for these correlations is to measure how they have evolved over cosmic time. Our ACS imaging of 20 Seyfert 1 galaxies at z=0.37 showed them to have smaller bulges (by a factor of 3) for a given central black hole mass than is found in galaxies in the present-day universe. However, since all our sample galaxies had black hole masses in the range 10^8.0--8.5 Msun, we could only measure the OFFSET in black hole mass to bulge luminosity ratios from the present epoch. By extending this study to black hole masses another factor of 10 lower, we propose to determine the full CORRELATION of black hole mass with host galaxy properties at a lookback time of 4 Gyrs and to test mass-dependency of the evolution. We have selected 14 Seyfert galaxies from SDSS DR5 whose narrow Hbeta emission lines (and estimated nuclear luminosities) imply that they have black hole masses around 10^7 Msuns. We will soon complete our Keck spectroscopic measures of their bulge velocity dispersions. We need a 1-orbit NICMOS image of each galaxy to separate its nonstellar luminosity from its bulge and disk. This will allow us to make the first determination of the full black hole/bulge relations at z=0.37 (e.g. M- and M-sigma), as well as a test of whether active galaxies obey the Fundamental Plane relation at that epoch. NIC3 11080 Exploring the Scaling Laws of Star Formation As a variety of surveys of the local and distant Universe are approaching a full census of galaxy populations, our attention needs to turn towards understanding and quantifying the physical mechanisms that trigger and regulate the large-scale star formation rates {SFRs} in galaxies. NIC3 11334 NICMOS Cycle 16 Spectrophotometry Observation of the three primary WD flux standards must be repeated to refine the NICMOS absolute calibration and monitor for sensitivity degradation. So far, NICMOS grism spectrophotometry is available for only ~16 stars with good STIS spectra at shorter wavelengths. There are more in the HST CALSPEC standard star data base with good STIS spectra that would also become precise IR standards with NICMOS absolute SED measurements. Monitoring the crucial three very red stars (M, L, T) for variability and better S/N in the IR. Apparent variability was discovered at shorter wavelengths during the ACS cross-calibration work that revealed a ~2% discrepancy of the cool star fluxes with respect to the hot primary WD standards. About a third of these stars are bright enough to do in one orbit, the rest require 2 orbits. 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************** 09**************** 09 FGS REacq************** 05**************** 05 OBAD with Maneuver **** 28**************** 28 SIGNIFICANT EVENTS: (None) |
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