NASA Hubble Space Telescope Status Update #4989

HUBBLE SPACE TELESCOPE DAILY REPORT #4989

PERIOD COVERED: 5am December 9 – 5am December 10, 2009 (DOY 343/10:00z-344/10:00z)

OBSERVATIONS SCHEDULED

ACS/WFC3 11879

CCD Daily Monitor (Part 1)

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 352 orbits (22 weeks) from 31 August 2009 to 31 January 2010.

ACS/WFC3/IR 11343

Identifying the Host Galaxies for Optically Dark Gamma-Ray Bursts

We propose to use the high spatial resolution capabilities of Chandra to obtain precise positions for a sample of Gamma-ray bursts (GRBs) with no optical afterglows, where the optical light is suppressed relative to the X-ray flux. These bursts are likely to be highly obscured and may have different environments from the optically bright GRBs. Our Chandra observations will (unlike Swift-XRT positions) allow for the unique identification of a host galaxy. To locate these host galaxies we will follow up our Chandra positions with deep optical and IR observations with HST. The ultimate aim is to understand any differences between the host galaxies of optically dark and bright GRBs, and how these affect the use of GRBs as tracers of star formation and galaxy evolution at high redshift.

COS/FUV 11895

FUV Detector Dark Monitor

The purpose of this proposal is to monitor the FUV detector dark rate by taking long science exposures without illuminating the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA. Dependence of dark rate as function of time will also be tracked.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate by taking long science exposures with no light on the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA. Dependence of dark rate as function of time will also be tracked.

COS/NUV/FUV/STIS/CCD/MA1 11692

The LMC as a QSO Absorption Line System

We propose to obtain high resolution, high signal-to-noise observations of QSOs behind the Large Magellanic Clouds. These QSOs are situated beyond the star forming disk of the galaxy, giving us the opportunity to study the distribution of metals and energy in regions lacking significant star formation. In particular, we will derive the metallicities and study the ionization characteristics of LMC gas at impact parameters 3-17 kpc. We will compare our results with high-z QSO absorption line systems.

NIC1/WFC3/IR 11205

The Effects of Multiplicity on the Evolution of Young Stellar Objects: A NICMOS Imaging Study

We propose to use NICMOS to investigate the multiplicity of young stellar objects (YSOs) in the Orion B molecular cloud. Previous observations with the Spitzer Space Telescope have revealed a remarkable star forming filament near the NGC 2068 reflection nebula. The population of YSOs associated with the filament exhibit a surprisingly wide range of circumstellar evolutionary states, from deeply embedded protostars to T Tauri accretion disks. Many of the circumstellar disks themselves show evidence for significant dust evolution, including grain growth and settling and cleared inner holes, apparently in spite of the very young age of these stars. We will estimate the binary fraction of a representative sample of objects in these various stages of evolution in order to test whether companions may play a significant role in that evolution.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to 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/IR 11235

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared selected galaxies exceeds that of optically selected galaxies. These `luminous infrared galaxies’ (LIRGs) are primarily interacting or merging disk galaxies undergoing enhanced star formation and Active Galactic Nuclei (AGN) activity, possibly triggered as the objects transform into massive S0 and elliptical merger remnants. We propose NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88 L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample (RBGS: i.e., 60 micron flux density > 5.24 Jy). This sample is ideal not only in its completeness and sample size, but also in the proximity and brightness of the galaxies. The superb sensitivity and resolution of NICMOS NIC2 on HST enables a unique opportunity to study the detailed structure of the nuclear regions, where dust obscuration may mask star clusters, AGN, and additional nuclei from optical view, with a resolution significantly higher than possible with Spitzer IRAC. This survey thus provides a crucial component to our study of the dynamics and evolution of IR galaxies presently underway with Wide-Field, HST ACS/WFC3, and Spitzer IRAC observations of these 88 galaxies. Imaging will be done with the F160W filter (H-band) to examine as a function of both luminosity and merger stage: (i) the luminosity and distribution of embedded star clusters, (ii) the presence of optically obscured AGN and nuclei, (iii) the correlation between the distribution of 1.6 micron emission and the mid-IR emission as detected by Spitzer IRAC, (iv) the evidence of bars or bridges that may funnel fuel into the nuclear region, and (v) the ages of star clusters for which photometry is available via ACS/WFC3 observations. The NICMOS data, combined with the HST ACS, Spitzer, and GALEX observations of this sample, will result in the most comprehensive study of merging and interacting galaxies to date.

WFC3/IR 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still largely an open problem in cosmology: how does the Universe evolve from large linear scales dominated by dark matter to the highly non-linear scales of galaxies, where baryons and dark matter both play important, interacting, roles? To understand the complex physical processes involved in their formation scenario, and why they have the tight scaling relations that we observe today (e.g. the Fundamental Plane), it is critically important not only to understand their stellar structure, but also their dark-matter distribution from the smallest to the largest scales. Over the last three years the SLACS collaboration has developed a toolbox to tackle these issues in a unique and encompassing way by combining new non-parametric strong lensing techniques, stellar dynamics, and most recently weak gravitational lensing, with high-quality Hubble Space Telescope imaging and VLT/Keck spectroscopic data of early-type lens systems. This allows us to break degeneracies that are inherent to each of these techniques separately and probe the mass structure of early-type galaxies from 0.1 to 100 effective radii. The large dynamic range to which lensing is sensitive allows us both to probe the clumpy substructure of these galaxies, as well as their low-density outer haloes. These methods have convincingly been demonstrated, by our team, using smaller pilot-samples of SLACS lens systems with HST data. In this proposal, we request observing time with WFC3 and NICMOS to observe 53 strong lens systems from SLACS, to obtain complete multi-color imaging for each system. This would bring the total number of SLACS lens systems to 87 with completed HST imaging and effectively doubles the known number of galaxy- scale strong lenses. The deep HST images enable us to fully exploit our new techniques, beat down low-number statistics, and probe the structure and evolution of early-type galaxies, not only with a uniform data-set an order of magnitude larger than what is available now, but also with a fully-coherent and self-consistent methodological approach!

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/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 11730 Continued Proper Motions of the Magellanic Clouds: Orbits, Internal Kinematics, and Distance In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in the Magellanic Clouds centered on background quasars. We used these data to determine the proper motions of the LMC and SMC to better than 5% and 15% respectively. The results had a number of unexpected implications for the Milky Way-LMC-SMC system and received considerable attention in the literature and in the press. The implied three-dimensional velocities are larger than previously believed and close to the escape velocity in a standard 10^12 solar mass Milky Way dark halo. Our orbit calculations suggest the Clouds may not be bound to the Milky Way or may just be on their first passage, both of which are unexpected in view of traditional interpretations of the Magellanic Stream. Alternatively, the Milky Way dark halo may be a factor two more massive than previously believed, which would be surprising in view of other observational constraints. Also, the relative velocity between the LMC and SMC was larger than expected, leaving open the possibility that the Clouds may not be bound to each other. To further verify and refine our results we requested an additional epoch data in Cycle 16 which is being executed with WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC field shows that the field proper motion using all three epochs of data is consistent within 1-sigma with the two-epoch data, thus verifying that there are no major systematic effects in our previous measurements. The random errors, however, are only smaller by a factor of 1.4 because of the relatively large errors in the WFPC2 data. A prediction for a fourth epoch with measurement errors similar to epochs 1 and 2 shows that the uncertainties will improve by a factor of 3. This will allow us to better address whether the Clouds are indeed bound to each other and to the Milky Way. It will also allow us to constrain the internal motions of various populations within the Clouds, and to determine a distance to the LMC using rotational parallax. Continuation of this highly successful program is therefore likely to provide important additional insights. Execution in SNAPshot mode guarantees maximally efficient use of HST resources. 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. WFC3/UVIS/IR 11644 A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into the Formation of the Outer Solar System The eight planets overwhelmingly dominate the solar system by mass, but their small numbers, coupled with their stochastic pasts, make it impossible to construct a unique formation history from the dynamical or compositional characteristics of them alone. In contrast, the huge numbers of small bodies scattered throughout and even beyond the planets, while insignificant by mass, provide an almost unlimited number of probes of the statistical conditions, history, and interactions in the solar system. To date, attempts to understand the formation and evolution of the Kuiper Belt have largely been dynamical simulations where a hypothesized starting condition is evolved under the gravitational influence of the early giant planets and an attempt is made to reproduce the current observed populations. With little compositional information known for the real Kuiper Belt, the test particles in the simulation are free to have any formation location and history as long as they end at the correct point. Allowing compositional information to guide and constrain the formation, thermal, and collisional histories of these objects would add an entire new dimension to our understanding of the evolution of the outer solar system. While ground based compositional studies have hit their flux limits already with only a few objects sampled, we propose to exploit the new capabilities of WFC3 to perform the first ever large-scale dynamical-compositional study of Kuiper Belt Objects (KBOs) and their progeny to study the chemical, dynamical, and collisional history of the region of the giant planets. The sensitivity of the WFC3 observations will allow us to go up to two magnitudes deeper than our ground based studies, allowing us the capability of optimally selecting a target list for a large survey rather than simply taking the few objects that can be measured, as we have had to do to date. We have carefully constructed a sample of 120 objects which provides both overall breadth, for a general understanding of these objects, plus a large enough number of objects in the individual dynamical subclass to allow detailed comparison between and within these groups. These objects will likely define the core Kuiper Belt compositional sample for years to come. While we have many specific results anticipated to come from this survey, as with any project where the field is rich, our current knowledge level is low, and a new instrument suddenly appears which can exploit vastly larger segments of the population, the potential for discovery — both anticipated and not — is extraordinary. WFC3/UVIS/IR 11700 Bright Galaxies at z>7.5 with a WFC3 Pure Parallel Survey

The epoch of reionization represents a special moment in the history of the Universe as it is during this era that the first galaxies and star clusters are formed. Reionization also profoundly affects the environment where subsequent generations of galaxies evolve. Our overarching goal is to test the hypothesis that galaxies are responsible for reionizing neutral hydrogen. To do so we propose to carry out a pure parallel WFC3 survey to constrain the bright end of the redshift z>7.5 galaxy luminosity function on a total area of 176 arcmin^2 of sky. Extrapolating the evolution of the luminosity function from z~6, we expect to detect about 20 Lyman Break Galaxies brighter than M_* at z~8 significantly improving the current sample of only a few galaxies known at these redshifts. Finding significantly fewer objects than predicted on the basis of extrapolation from z=6 would set strong limits to the brightness of M_*, highlighting a fast evolution of the luminosity function with the possible implication that galaxies alone cannot reionize the Universe. Our observations will find the best candidates for spectroscopic confirmation, that is bright z>7.5 objects, which would be missed by small area deeper surveys. The random pointing nature of the program is ideal to beat cosmic variance, especially severe for luminous massive galaxies, which are strongly clustered. In fact our survey geometry of 38 independent fields will constrain the luminosity function like a contiguous single field survey with two times more area at the same depth. Lyman Break Galaxies at z>7.5 down to m_AB=26.85 (5 sigma) in F125W will be selected as F098M dropouts, using three to five orbits visits that include a total of four filters (F606W, F098M, F125W, F160W) optimized to remove low-redshift interlopers and cool stars. Our data will be highly complementary to a deep field search for high-z galaxies aimed at probing the faint end of the luminosity function, allowing us to disentangle the degeneracy between faint end slope and M_* in a Schechter function fit of the luminosity function. We waive proprietary rights for the data. In addition, we commit to release the coordinates and properties of our z>7.5 candidates within one month from the acquisition of each field.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#12116 GSAcq(1,2,1) @343/14:22:37z failed to RGA control with Search Radius Limit exceeded on FGS1 @ 343/14:29:43z

Observations affected: WFPC #94-98 Proposal #11235

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                      SCHEDULED      SUCCESSFUL

FGS GSAcq              10              9

FGS REAcq               5              5

OBAD with Maneuver      9              9

SIGNIFICANT EVENTS: (None)