NASA Hubble Space Telescope Daily Report #5074
HUBBLE SPACE TELESCOPE DAILY REPORT #5074
PERIOD COVERED: 5am April 13 – 5am April 14, 2010 (DOY 103/09:00z-104/09:00z)
OBSERVATIONS SCHEDULED
ACS/WFC3 11882
CCD Hot Pixel Annealing
This program continues the monthly anneal that has taken place every four weeks for the last three cycles. We now obtain WFC biases and darks before and after the anneal in the same sequence as is done for the ACS daily monitor (now done 4 times per week). So the anneal observation supplements the monitor observation sets during the appropriate week. Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data will be obtained over a range of signal levels for the Wide Field Channel (WFC). 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. The High Resolution Channel (HRC) visits have been removed since it could not be repaired during SM4.
This program also assesses the read noise, bias structure, and amplifier cross-talk of ACS/WFC using the GAIN=1.4 A/D conversion setting. This investigation serves as a precursor to a more comprehensive study of WFC performance using GAIN=1.4.
COS/NUV/FUV/WFC3/UVIS/IR 11520
COS-GTO: QSO Absorbers, Galaxies and Large-Scale Structures in the Local Universe
This is a program to probe the large scale structure of baryons in the universe, including addressing questions of baryon fraction, physical conditions and relationships between absorbers and large-scale structures of galaxies. Besides these specific goals, this proposed GTO program also probes a large enough total path length in Ly alpha and OVI to add significantly to what STIS/FUSE has already observed. Several Galactic High Velocity Cloud Complexes also are probed by these sightlines, particularly the M Complex. The total path length of this proposed program for Ly alpha large-scale structure surveys is delta_z~5.5.
We have selected a variety of targets to address these questions, under the following subcategories:
1. Target 8 bright BL Lac objects to search for low contrast Ly alpha absorbers from the warm- hot interstellar medium (WHIM).
2. Ly alpha cloud sizes: The targets are a bright AGN pair which yield tangential distance separations of 100–500 kpc at z=0.01–0.05, where galaxy surveys are excellent. This pair has two filaments and two voids in this distance range.
3. Probes of starburst outflows: The targets are bright AGN, <= 100 kpc in projection out of the minor axis of nearby starburst galaxies. 4. A large galaxy’s gaseous halo: Three probes of the kinematics and metallicity of a single L* galaxy halo. These observations includes G130M, G160M exposures at SNR~20 and G285M at 2850A and SNR~10 for MgII. The 2L* galaxy, ESO 157-G049 (cz=1678 km/s), being probed by these sightlines has an available H I 21cm map from ATCA, H alpha imaging from CTIO and long- slit spectra from MSSSO. 5. Dwarf galaxy winds: These targets probe the kinematics and metallicities of outflows from active and inactive (in terms of star formation) dwarfs. FGS 11792 Extrasolar Planet XO-2b We propose observations of the newly discovered extrasolar planet XO-2b and its twin star XO-2. When combined with the transit light curve, the FGS-derived parallax will constrain the stellar mass of the host star XO-2. From the high signal-to-noise near-IR time series resulting from NICMOS grism spectroscopy, we will refine the system parameters, in particular radii of the star and planet. From the same data, we will search for evidence of water vapor in the atmosphere via transmission spectroscopy. Differential observations with NICMOS in the spectroscopic mode will be used to search for the small spectral changes that occur during planetary transits resulting from absorption of stellar light as it passes through the planetary atmosphere. Water is an important constituent, the detection of which would provide information on Oxygen, and it has a convenient strong band well-positioned for NICMOS. NIC2/WFC3/IR 11548 Infrared Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation We propose NICMOS and WFC3/IR observations of a sample of 252 protostars identified in the Orion A cloud with the Spitzer Space Telescope. These observations will image the scattered light escaping the protostellar envelopes, providing information on the shapes of outflow cavities, the inclinations of the protostars, and the overall morphologies of the envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron spectra of 75 of the protostars. Combining these new data with existing 3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured with the Spitzer Space Telescope, we will determine the physical properties of the protostars such as envelope density, luminosity, infall rate, and outflow cavity opening angle. By examining how these properties vary with stellar density (i.e. clusters vs. groups vs. isolation) and the properties of the surrounding molecular cloud; we can directly measure how the surrounding environment influences protostellar evolution, and consequently, the formation of stars and planetary systems. Ultimately, this data will guide the development of a theory of protostellar evolution. STIS/CC 11845 CCD Dark Monitor Part 2 Monitor the darks for the STIS CCD. STIS/CC 11847 CCD Bias Monitor-Part 2 Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns. WFC3/ACS/UVIS 11603 A Comprehensive Study of Dust Formation in Type II Supernovae with HST, Spitzer, and Gemini The recent discovery of three extremely bright Type II SNe, (2007it, 2007oc, 2007od) gives us a unique opportunity to combine observations with HST, Spitzer, and Gemini to study the little understood dust formation process in Type II Sne. Priority 1 Spitzer Cycle 5 and band 1 Gemini 2008A time has already been approved for this project. Since late-time Type II Sne are faint and tend to be in crowded fields, we need the high sensitivity and high spatial resolution of ACS and NICMOS/NIC2 for these observations. This project is motivated by the recent detection of large amounts of dust in high redshift galaxies. The dust in these high-z galaxies must come from young, massive stars so Type II Sne could be potential sources. The mechanism and the efficiency of dust condensation in Type II SN ejecta are not well understood, largely due to the lack of observational data. We plan to produce a unique dataset, combining spectroscopy and imaging in the visible, near- and mid-IR covering the key phase, 400-700 days after maximum when dust is known to form in the SN ejecta. Therefore, we are proposing for coordinated HST/NOAO observations (HST ACS, NICMOS/NIC2 & Gemini/GMOS and TReCS) which will be combined with our Spitzer Cycle 5 data to study these new bright Sne. The results of this program will place strong constraints on the formation of dust seen in young high redshift (z>5) galaxies.
WFC3/IR 11666
Chilly Pairs: A Search for the Latest-type Brown Dwarf Binaries and the Prototype Y Dwarf
We propose to use HST/NICMOS to image a sample of 27 of the nearest (< 20 pc) and lowest luminosity T-type brown dwarfs in order to identify and characterize new very low mass binary systems. Only 3 late-type T dwarf binaries have been found to date, despite that fact that these systems are critical benchmarks for evolutionary and atmospheric models at the lowest masses. They are also the most likely systems to harbor Y dwarf companions, an as yet unpopulated putative class of very cold (T < 600 K) brown dwarfs. Our proposed program will more than double the number of T5-T9 dwarfs imaged at high resolution, with an anticipated yield of ~5 new binaries with initial characterization of component spectral types. We will be able to probe separations sufficient to identify systems suitable for astrometric orbit and dynamical mass measurements. We also expect one of our discoveries to contain the first Y-type brown dwarf. Our proposed program complements and augments ongoing ground-based adaptive optics surveys and provides pathway science for JWST. WFC3/IR/S/C 11929 IR Dark Current Monitor Analyses of ground test data showed that dark current signals are more reliably removed from science data using darks taken with the same exposure sequences as the science data, than with a single dark current image scaled by desired exposure time. Therefore, dark current images must be collected using all sample sequences that will be used in science observations. These observations will be used to monitor changes in the dark current of the WFC3-IR channel on a day-to-day basis, and to build calibration dark current ramps for each of the sample sequences to be used by Gos in Cycle 17. For each sample sequence/array size combination, a median ramp will be created and delivered to the calibration database system (CDBS). WFC3/UVIS 11595 Turning Out the Light: A WFC3 Program to Image z>2 Damped Lyman Alpha Systems
We propose to directly image the star-forming regions of z>2 damped Lya systems (DLAs) using the WFC3/UVIS camera on the Hubble Space Telescope. In contrast to all previous attempts to detect the galaxies giving rise to high redshift DLAs, we will use a novel technique that completely removes the glare of the background quasar. Specifically, we will target quasar sightlines with multiple DLAs and use the higher redshift DLA as a “blocking filter” (via Lyman limit absorption) to eliminate all FUV emission from the quasar. This will allow us to carry out a deep search for FUV emission from the lower redshift DLA, shortward of the Lyman limit of the higher redshift absorber. The unique filter set and high spatial resolution afforded by WFC3/UVIS will then enable us to directly image the lower redshift DLA and thus estimate its size, star- formation rate and impact parameter from the QSO sightline. We propose to observe a sample of 20 sightlines, selected primarily from the SDSS database, requiring a total of 40 HST orbits. The observations will allow us to determine the first FUV luminosity function of high redshift DLA galaxies and to correlate the DLA galaxy properties with the ISM characteristics inferred from standard absorption-line analysis to significantly improve our understanding of the general DLA population.
WFC3/UVIS 11714
Snapshot Survey for Planetary Nebulae in Local Group Globular Clusters
Planetary nebulae (PNe) in globular clusters (GCs) raise a number of interesting issues related to stellar and galactic evolution. The number of PNe known in Milky Way GCs, four, is surprisingly low if one assumes that all stars pass through a PN stage. However, it is likely that the remnants of stars now evolving in galactic GCs leave the AGB so slowly that any ejected nebula dissipates long before the star becomes hot enough to ionize it. Thus there should not be ANY PNe in Milky Way GCs–but there are four! It has been suggested that these Pne are the result of mergers of binary stars within GCs, i.e., that they are descendants of blue stragglers. The frequency of occurrence of PNe in external galaxies poses more questions, because it shows a range of almost an order of magnitude.
I propose a SNAPshot survey aimed at discovering PNe in the GC systems of Local Group galaxies outside the Milky Way. These clusters, some of which may be much younger than their counterparts in our galaxy, might contain many more PNe than those of our own galaxy. I will use the standard technique of emission-line and continuum imaging, which easily discloses PNe. This proposal continues a WFPC2 program started in Cycle 16, but with the more powerful WFC3. As a by-product, the survey will also produce color-magnitude diagrams for numerous clusters for the first time, reaching down to the horizontal branch.
WFC3/UVIS 11905
WFC3 UVIS CCD Daily Monitor
The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS).
WFC3/UVIS 11908
Cycle 17: UVIS Bowtie Monitor
Ground testing revealed an intermittent hysteresis type effect in the UVIS detector (both CCDs) at the level of ~1%, lasting hours to days. Initially found via an unexpected bowtie-shaped feature in flatfield ratios, subsequent lab tests on similar e2v devices have since shown that it is also present as simply an overall offset across the entire CCD, i.e., a QE offset without any discernable pattern. These lab tests have further revealed that overexposing the detector to count levels several times full well fills the traps and effectively neutralizes the bowtie. Each visit in this proposal acquires a set of three 3×3 binned internal flatfields: the first unsaturated image will be used to detect any bowtie, the second, highly exposed image will neutralize the bowtie if it is present, and the final image will allow for verification that the bowtie is gone.
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 6 6
FGS REAcq 8 8
OBAD with Maneuver 4 4
SIGNIFICANT EVENTS: (None)
