Status Report

NASA Hubble Space Telescope Daily Report #5113

By SpaceRef Editor
June 10, 2010
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Continuing to Collect World Class Science

PERIOD COVERED: 5am June 8 – 5am June 9, 2010 (DOY 159/09:00z-160/09:00z)


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)


12298 – GSAcq(2,1,1) at 159/19:19:42z resulted in fine lock back-up on FGS1 due to scan step limit exceeded on FGS2.

Observations possibly affected: COS 37- 41, Proposal ID#11687.



FGS GSAcq 10 10
FGS REAcq 6 6
OBAD with Maneuver 7 7



ACS/WFC 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.

ACS/WFC 11995

CCD Daily Monitor (Part 2)

This program comprises basic tests for measuring the read noise and dark current of the ACS WFC and for tracking the growth of hot pixels. The recorded frames are used to create bias and dark reference images for science data reduction and calibration. This program will be executed four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To facilitate scheduling, this program is split into three proposals. This proposal covers 320 orbits (20 weeks) from 1 February 2010 to 20 June 2010.


Formation and Evolution of Massive Galaxies in the Richest Environments at 1.5 < z < 2.0 We propose to image seven 1.5< z<2 clusters and groups from the IRAC Shallow Cluster Survey with WFC3 and ACS in order to study the formation and evolution of massive galaxies in the richest environments in the Universe in this important redshift range. We will measure the evolution of the sizes and morphologies of massive cluster galaxies, as a function of redshift, richness, radius and local density. In combination with allocated Keck spectroscopy, we will directly measure the dry merger fraction in these clusters, as well as the evolution of Brightest Cluster Galaxies (BCGs) over this redshift range where clear model predictions can be confronted. Finally we will measure both the epoch of formation of the stellar populations and the assembly history of that stellar mass, the two key parameters in the modern galaxy formation paradigm. ACS/WFC/WFC3/UVI 11613 GHOSTS: Stellar Outskirts of Massive Spiral Galaxies We propose to continue our highly successful GHOSTS HST survey of the resolved stellar populations of nearby, massive disk galaxies using SNAPs. These observations provide star counts and color-magnitude diagrams 2-3 magnitudes below the tip of the Red Giant Branch of the outer disk and halo of each galaxy. We will measure the metallicity distribution functions and stellar density profiles from star counts down to very low average surface brightnesses, equivalent to ~32 V-mag per square arcsec. This proposal will substantially improve our unique sampling of galaxy outskirts. Our targets cover a range in galaxy mass, luminosity, inclination, and morphology. As function of these galaxy properties this survey provides: – the most extensive, systematic measurement of radial light profiles and axial ratios of the diffuse stellar halos and outer disks of spiral galaxies; – a comprehensive analysis of halo metallicity distributions as function of galaxy type and position within the galaxy; – an unprecedented study of the stellar metallicity and age distribution in the outer disk regions where the disk truncations occur; – the first comparative study of globular clusters and their field stellar populations. We will use these fossil records of the galaxy assembly process to test halo formation models within the hierarchical galaxy formation scheme. COS/FUV 11687 SNAPing Coronal Iron This is a Snapshot Survey to explore two forbidden lines of highly ionized iron in late-type coronal sources. Fe XII 1349 (T~ 2 MK) and Fe XXI 1354 (T~ 10 MK) — well known to Solar Physics — have been detected in about a dozen cool stars, mainly with HST/STIS. The UV coronal forbidden lines are important because they can be observed with velocity resolution of better than 15 km/s, whereas even the state-of-the-art X-ray spectrometers on Chandra can manage only 300 km/s in the kilovolt band where lines of highly ionized iron more commonly are found. The kinematic properties of hot coronal plasmas, which are of great interest to theorists and modelers, thus only are accessible in the UV at present. The bad news is that the UV coronal forbidden lines are faint, and were captured only in very deep observations with STIS. The good news is that 3rd-generation Cosmic Origins Spectrograph, slated for installation in HST by SM4, in a mere 25 minute exposure with its G130M mode can duplicate the sensitivity of a landmark 25-orbit STIS E140M observation of AD Leo, easily the deepest such exposure of a late-type star so far. Our goal is to build up understanding of the properties of Fe XII and Fe XXI in additional objects beyond the current limited sample: how the lineshapes depend on activity, whether large scale velocity shifts can be detected, and whether the dynamical content of the lines can be inverted to map the spatial morphology of the stellar corona (as in “Doppler Imaging”). In other words, we want to bring to bear in the coronal venue all the powerful tricks of spectroscopic remote sensing, well in advance of the time that this will be possible exploiting the corona’s native X-ray radiation. The 1290-1430 band captured by side A of G130M also contains a wide range of key plasma diagnostics that form at temperatures from below 10, 000 K (neutral lines of CNO), to above 200, 000 K (semi-permitted O V 1371), including the important bright multiplets of C II at 1335 and Si IV at 1400; yielding a diagnostic gold mine for the subcoronal atmosphere. Because of the broad value of the SNAP spectra, beyond the coronal iron project, we waive the normal proprietary rights. COS/NUV 11705 Physical Properties of Quasar Outflows: From BALs to mini-BALs Accretion disk outflows are important components of quasar environments. They might play a major role in facilitating accretion, regulating star formation in the host galaxies and distributing metals to the surrounding gas. They reveal themselves most conspicuously via broad absorption lines (BALs), but they appear even more frequently in other guises such as the weaker and narrower “mini-BALs.” How are these diverse outflow features related? Are mini-BALs really just “mini” versions of the BALs, or do they represent a fundamentally different type of outflow, with different degrees of ionization, column densities, mass loss rates, physical origins, etc.? We propose HST-COS spectroscopy to make the first quantitative assessment of the outflow physical conditions across the full range of weak/narrow mini-BALs to strong/broad BALs. Our strategy is to measure key diagnostic lines (SVI, OVI, CIII, SIV, PV, etc.) at 930A – 1130A (rest-frame) in a sample of 7 outflow quasars with known mini-BALs through weak BALs. We will then 1) combine the COS data with ground-based spectra of the same quasars to include more lines (CIV, SiIV) at longer wavelengths, and 2) include in our analysis a nearly identical UV/optical dataset obtained previously for a sample of quasars with strong BALs. Our study of this combined dataset will be an essential next step toward a more global understanding of quasar outflows. STIS/CCD 11845 CCD Dark Monitor Part 2 Monitor the darks for the STIS CCD. STIS/CCD 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/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 11696 Infrared Survey of Star Formation Across Cosmic Time We propose to use the unique power of WFC3 slitless spectroscopy to measure the evolution of cosmic star formation from the end of the reionization epoch at z>6 to the close of the galaxy-building era at z~0.3.Pure parallel observations with the grisms have proven to be efficient for identifying line emission from galaxies across a broad range of redshifts. The G102 grism on WFC3 was designed to extend this capability to search for Ly-alpha emission from the first galaxies. Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will observe about 40 deep (4-5 orbit) fields with the combination of G102 and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.

Our primary science goals at the highest redshifts are: (1) Detect Lya in ~100 galaxies with z>5.6 and measure the evolution of the Lya luminosity function, independent of of cosmic variance; 2) Determine the connection between emission-line selected and continuum-break selected galaxies at these high redshifts, and 3) Search for the proposed signature of neutral hydrogen absorption at re-ionization. At intermediate redshifts we will (4) Detect more than 1000 galaxies in Halpha at 0.5< z<1.8 to measure the evolution of the extinction-corrected star formation density across the peak epoch of star formation. This is over an order-of-magnitude improvement in the current statistics, from the NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from 0.5< z<2.2; and (6) Estimate the evolution in reddening and metallicty in star-forming galaxies and measure the evolution of the Seyfert population. For hundreds of spectra we will be able to measure one or even two line pair ratios -- in particular, the Balmer decrement and [OII]/[OIII] are sensitive to gas reddening and metallicity. As a bonus, the G102 grism offers the possiblity of detecting Lya emission at z=7-8.8. To identify single-line Lya emitters, we will exploit the wide 0.8–1.9um wavelength coverage of the combined G102+G141 spectra. All [OII] and [OIII] interlopers detected in G102 will be reliably separated from true LAEs by the detection of at least one strong line in the G141 spectrum, without the need for any ancillary data. We waive all proprietary rights to our data and will make high-level data products available through the ST/ECF. WFC3/IR 11735 The LSD project: dynamics, merging and stellar populations of a sample of well-studied LBGs at z~3 A large observational effort with the ground-based ESO/VLT telescopes allowed us to obtain deep, spatially-resolved, near-IR spectra of complete sample of 11 Lyman-Break Galaxies at z~3.1. These observations were used to obtain, for the first time, the metallicity and the dynamical properties of a sample of objects that, albeit small, is representative of the total population of the LBGs. We propose to use HST to obtain high-resolution optical and near-IR images of this sample of LBGs in order to study the broad-band morphology and the stellar light distribution of these galaxies. These images, exploiting the superior spatial resolution of HST images and the low-background : 1- will allow a precise measure of the dynamical mass from the velocity field derived with spectroscopy; 2- will permit a comparison of the distribution of star formation (from the line emission) with the underlying stellar population, and, 3- will be used to check if the complex velocity field and the multiple line-emitting regions detected in most targets can be ascribed to on-going mergers. This accurate study will shed light on a number of unsolved problems still affecting the knowledge of the LBGs. WFC3/IR/WFC3/UVI 11557 The Nature of low-ionization BAL QSOs The rare subclass of optically-selected QSOs known as low-ionization broad absorption line (LoBAL) QSOs show signs of high-velocity gas outflows and reddened continua indicative of dust obscuration. Recent studies show that galaxies hosting LoBAL QSOs tend to be ultraluminous infrared systems that are undergoing mergers, and that have dominant young (< 100 Myr) stellar populations. Such studies support the idea that LoBAL QSOs represent a short-lived phase early in the life of QSOs, when powerful AGN-driven winds are blowing away the dust and gas surrounding the QSO. If so, understanding LoBALs would be critical in the study of phenomena regulating black hole and galaxy evolution, such as AGN feedback and the early stages of nuclear accretion. These results, however, come from very small samples that may have serious selection biases. We are therefore taking a more aggressive approach by conducting a systematic multiwavelength study of a volume limited sample of LoBAL QSOs at 0.5 < z < 0.6 drawn from SDSS. We propose to image their host galaxies in two bands using WFC3/UVIS and WFC3/IR to study the morphologies for signs of recent tidal interactions and to map their interaction and star forming histories. We will thus determine whether LoBAL QSOs are truly exclusively found in young merging systems that are likely to be in the early stages of nuclear accretion. WFC3/UVI 11594 A WFC3 Grism Survey for Lyman limit absorption at z=2 We propose to conduct a spectroscopic survey of Lyman limit absorbers at redshifts 1.8 < z < 2.5, using WFC3 and the G280 grism. This proposal intends to complete an approved Cycle 15 SNAP program (#10878) which was cut short due to the ACS failure. We have selected 64 quasars at 2.3 < z < 2.6 from the Sloan Digital Sky Survey Spectroscopic Quasar sample, for which no BAL signature is found at the QSO redshift and no strong metal absorption lines are present at z > 2.3 along the lines of sight. The survey has three main

observational goals. First, we will determine the redshift frequency dn/dz of the LLS over the column density range 16.0 < log(NHI) < 20.3 cm^-2. Second, we will measure the column density frequency distribution f(N) for the partial Lyman limit systems (PLLS) over the column density range 16.0 < log(NHI) < 17.5 cm^-2. Third, we will identify those sightlines which could provide a measurement of the primordial D/H ratio. By carrying out this survey, we can also help place meaningful constraints on two key quantities of cosmological relevance. First, we will estimate the amount of metals in the LLS using the f(N), and ground based observations of metal line transitions. Second, by determining f(N) of the PLLS, we can constrain the amplitude of the ionizing UV background at z~2 to a greater precision. This survey is ideal for a snapshot observing program, because the on-object integration times are all well below 30 minutes, and follow-up observations from the ground require minimal telescope time due to the QSO sample being bright. WFC3/UVI 11697 Proper Motion Survey of Classical and SDSS Local Group Dwarf Galaxies Using the superior resolution of HST, we propose to continue our proper motion survey of Galactic dwarf galaxies. The target galaxies include one classical dwarf, Leo II, and six that were recently identified in the Sloan Digital Sky Survey data: Bootes I, Canes Venatici I, Canes Venatici II, Coma Berenices, Leo IV, and Ursa Major II. We will observe a total of 16 fields, each centered on a spectroscopically- confirmed QSO. Using QSOs as standards of rest in measuring absolute proper motions has proven to be the most accurate and most efficient method. HST is our only option to quickly determine the space motions of the SDSS dwarfs because suitable ground-based imaging is only a few years old and such data need several decades to produce a proper motion. The two most distant galaxies in our sample will require time baselines of four years to achieve our goal of a 30-50 km/s uncertainty in the tangential velocity; given this and the finite lifetime of HST, it is imperative that first-epoch observations be taken in this cycle. The SDSS dwarfs have dramatically lower surface brightnesses and luminosities than the classical dwarfs. Proper motions are crucial for determining orbits of the galaxies and knowing the orbits will allow us to test theories for the formation and evolution of these galaxies and, more generally, for the formation of the Local Group. WFC3/UVI 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 (11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS). June 2, 2010 S.P.Korolev RSC Energia, Korolev, Moscow region

SpaceRef staff editor.