NASA Hubble Space Telescope Daily Report # 4583
HUBBLE SPACE TELESCOPE DAILY REPORT # 4583
Continuing to collect World Class Science
PERIOD COVERED: UT April 04,05,06, 2008 (DOY 095,096,097)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA calibration – CR Persistence Part 6
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 DARKSs. 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.
WFPC2 11509
Astrometric Centroiding for Saturated Stars
This is a WFPC2 program that will calibrate the use of diffraction spikes to centroid saturated stellar images. The purpose is to provide an astrometric calibration of this method, which has been used for a series of HST observations of Sirius and its companion, Sirius being so bright that it is saturated in the shortest possible WFPC2 exposures. We will obtain both unsaturated and saturated images of 109 Vir, a star of type A0 V whose color is very similar to that of Sirius, but it is more than 5 mag fainter. This will allow a direct calibration of any offsets between the centroid indicated by the diffraction spikes (or other PSF features) and the true stellar centroid.
WFPC2 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 starformation and galaxy evolution at high redshift.
NIC1/NIC2/NIC3 11330
NICMOS Cycle 16 Extended Dark
This takes a series of Darks in parallel to other instruments.
S/C 11320
NICMOS Focus Monitoring Cycle 16
This program is a version of the standard focus sweep used since cycle 7. It has been modified to go deeper and uses more narrow filters for improved focus determination. A new source was added in Cycle 14 in order to accommodate 2-gyro mode: the open cluster NGC1850. This source is part of the current proposal. The old target, the open cluster NGC3603, will be used whenever available and the new target used to fill the periods when NGC3603 is not visible. Steps: a) Use refined target field positions as determined from cycle 7 calibrations b) Use MULTIACCUM sequences of sufficient dynamic range to account for defocus c) Do a 17-point focus sweep, +/- 8mm about the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps. For NIC3 we step from -0.5mm to -9.5mm relative to mechanical zero, in steps of 1.0mm. d) Use PAM X/Y tilt and OTA offset slew compensations refined from previous focus monitoring/optical alignment activities.
NIC1/NIC2/NIC3 11319
NICMOS Photometric Stability Monitoring
This NICMOS calibration proposal carries out photometric monitoring observations during Cycle 15. The format is the same as the Cycle 14 version of the program (10725), but a few modifications were made with respect to the Cycle 12 program 9995 and Cycle 13 program 10381. Provisions had to be made to adopt to 2-gyro mode (G191B2B was added as extra target to provide target visibility through most of the year). Where before 4 or 7 dithers were made in a filter before we moved to the next filter, now we observe all filters at one position before moving to the next dither position. While the previous method was chosen to minimize the effect of persistence, we now realize that persistence may be connected to charge trapping and by moving through the filter such that the count rate increases, we reach equilibrium more quickly between charge being trapped and released. We have also increased exposure times where possible to reduce the charge trapping non-linearity effects.
WFPC2 11229
SEEDS: The Search for Evolution of Emission from Dust in Supernovae with HST and Spitzer
The role that massive stars play in the dust content of the Universe is extremely uncertain. It has long been hypothesized that dust can condense within the ejecta of supernovae {SNe}, however there is a frustrating discrepancy between the amounts of dust found in the early Universe, or predicted by nucleation theory, and inferred from SN observations. Our SEEDS collaboration has been carefully revisiting the observational case for dust formation by core- collapse SNe, in order to quantify their role as dust contributors in the early Universe. As dust condenses in expanding SN ejecta, it will increase in optical depth, producing three simultaneously observable phenomena: {1} increasing optical extinction; {2} infrared {IR} excesses; and {3} asymmetric blue-shifted emission lines. Our SEEDS collaboration recently reported all three phenomena occurring in SN2003gd, demonstrating the success of our observing strategy, and permitting us to derive a dust mass of up to 0.02 solar masses created in the SN. To advance our understanding of the origin and evolution of the interstellar dust in galaxies, we propose to use HST’s WFPC2 and NICMOS instruments plus Spitzer’s photometric instruments to monitor ten recent core-collapse SNe for dust formation and, as a bonus, detect light echoes that can affect the dust mass estimates. These space-borne observations will be supplemented by ground-based spectroscopic monitoring of their optical emission line profiles. These observations would continue our 2-year HST and Spitzer monitoring of this phenomena in order to address two key questions: Do all SNe produce dust? and How much dust do they produce? As all the SN are within 15 Mpc, each SN stands an excellent chance of detection with HST and Spitzer and of resolving potential light echoes.
FGS 11210
The Architecture of Exoplanetary Systems
Are all planetary systems coplanar? Concordance cosmogony makes that prediction. It is, however, a prediction of extrasolar planetary system architecture as yet untested by direct observation for main sequence stars other than the Sun. To provide such a test, we propose to carry out FGS astrometric studies on four stars hosting seven companions. Our understanding of the planet formation process will grow as we match not only system architecture, but formed planet mass and true distance from the primary with host star characteristics for a wide variety of host stars and exoplanet masses. We propose that a series of FGS astrometric observations with demonstrated 1 millisecond of arc per-observation precision can establish the degree of coplanarity and component true masses for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}. In each case the companion is identified as such by assuming that the minimum mass is the actual mass. For the last target, a known stellar binary system, the companion orbit is stable only if coplanar with the AB binary orbit.
WFPC2 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 WFPC2 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!
WEPC2 11196
An Ultraviolet Survey 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 starbursts and creating/fueling central AGN. We propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W} UV imaging of a sample of 27 galaxies drawn from the complete IRAS Revised Bright Galaxy Sample {RBGS} LIRGs sample and known, from our Cycle 14 B and I-band ACS imaging observations, to have significant numbers of bright {23 < B < 21 mag} star clusters in the central 30 arcsec. The HST UV data will be combined with previously obtained HST, Spitzer, and GALEX images to {i} calculate the ages of the clusters as function of merger stage, {ii} measure the amount of UV light in massive star clusters relative to diffuse regions of star formation, {iii} assess the feasibility of using the UV slope to predict the far-IR luminosity {and thus the star formation rate} both among and within IR-luminous galaxies, and {iv} provide a much needed catalog of rest- frame UV morphologies for comparison with rest-frame UV images of high-z LIRGs and Lyman Break Galaxies. These observations will achieve the resolution required to perform both detailed photometry of compact structures and spatial correlations between UV and redder wavelengths for a physical interpretation our IRX-Beta results. The HST UV data, combined with the HST ACS, Spitzer, Chandra, and GALEX observations of this sample, will result in the most comprehensive study of luminous starburst galaxies to date.
NIC1/NIC2 11139
NICMOS Observations of the Microquasar GRS 1758-258
The galactic black hole candidate GRS 1758-258 is normally one of the brightest persistent gamma-ray sources in the vicinity of the galactic center. It is a microquasar with relativistic radio jets emanating from a central variable source. Microquasars are excellent nearby test laboratories for studying the complex accretion and outflow processes that take place near black hole horizons. Despite an accurate location provided by Chandra and the VLA and over a decade of careful ground-based studies, the optical/infrared counterpart to GRS 1758-258 remains unknown. A stellar counterpart is expected, but the current candidates are all more than 2 sigma from the center of the error circle. The ground-based infrared flux limits are also right at the values expected for the synchrotron emission from the outflow from the black hole, and possibly for the emission from the accretion disk. This leaves open the question as to what is powering this very energetic persistent source. Here we propose to use NICMOS to perform broad-band imaging of the GRS 1758- 258 error box. These images will be more than three magnitudes more sensitive than the current ground-based ones. The resulting spectra will reveal the thermal/non- thermal nature of the sources in the region of the error box, and the high spatial resolution images may reveal a jet structure. We propose to perform three visits of two orbits each spanning the suggested 18.45 day binary orbital period of the system: a correct counterpart identification should be confirmed by its variability. We will also aim to support the HST observations with X- and gamma-ray observations using Swift or INTEGRAL, and with longer wavelength observations from the ground.
WFPC2 11122
Expanding PNe: Distances and Hydro Models
We propose to obtain repeat narrowband images of a sample of eighteen planetary nebulae {PNe} which have HST/WFPC2 archival data spanning time baselines of a decade. All of these targets have previous high signal-to-noise WFPC2/PC observations and are sufficiently nearby to have readily detectable expansion signatures after a few years. Our main scientific objectives are {a} to determine precise distances to these PNe based on their angular expansions, {b} to test detailed and highly successful hydrodynamic models that predict nebular morphologies and expansions for subsamples of round/elliptical and axisymmetric PNe, and {c} to monitor the proper motions of nebular microstructures in an effort to learn more about their physical nature and formation mechanisms. The proposed observations will result in high-precision distances to a healthy subsample of PNe, and from this their expansion ages, luminosities, CSPN properties, and masses of their ionized cores. With good distances and our hydro models, we will be able to determine fundamental parameters {such as nebular and central star masses, luminosity, age}. The same images allow us to monitor the changing overall ionization state and to search for the surprisingly non-homologous growth patterns to bright elliptical PNe of the same sort seen by Balick & Hajian {2004} in NGC 6543. Non-uniform growth is a sure sign of active pressure imbalances within the nebula that require careful hydro models to understand.
NIC3 11120
A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center
The Galactic center (GC) is a unique site for a detailed study of a multitude of complex astrophysical phenomena, which may be common to nuclear regions of many galaxies. Observable at resolutions unapproachable in other galaxies, the GC provides an unparalleled opportunity to improve our understanding of the interrelationships of massive stars, young stellar clusters, warm and hot ionized gases, molecular clouds, large scale magnetic fields, and black holes. We propose the first large-scale hydrogen Paschen alpha line survey of the GC using NICMOS on the Hubble Space Telescope. This survey will lead to a high resolution and high sensitivity map of the Paschen alpha line emission in addition to a map of foreground extinction, made by comparing Paschen alpha to radio emission. This survey of the inner 75 pc of the Galaxy will provide an unprecedented and complete search for sites of massive star formation. In particular, we will be able to (1) uncover the distribution of young massive stars in this region, (2) locate the surfaces of adjacent molecular clouds, (3) determine important physical parameters of the ionized gas, (4) identify compact and ultra-compact HII regions throughout the GC. When combined with existing Chandra and Spitzer surveys as well as a wealth of other multi-wavelength observations, the results will allow us to address such questions as where and how massive stars form, how stellar clusters are disrupted, how massive stars shape and heat the surrounding medium, and how various phases of this medium are interspersed.
WFPC2 11113
Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution
The discovery of binaries in the Kuiper Belt and related small body populations is powering a revolutionary step forward in the study of this remote region. Three quarters of the known binaries in the Kuiper Belt have been discovered with HST, most by our snapshot surveys. The statistics derived from this work are beginning to yield surprising and unexpected results. We have found a strong concentration of binaries among low-inclination Classicals, a possible size cutoff to binaries among the Centaurs, an apparent preference for nearly equal mass binaries, and a strong increase in the number of binaries at small separations. We propose to continue this successful program in Cycle 16; we expect to discover at least 13 new binary systems, targeted to subgroups where these discoveries can have the greatest impact.
WFPC2 11111
A Search for an Intermediate Mass Black Hole in the Globular Cluster NGC 6266
We propose to search for an intermediate mass black hole (IMBH) in the core of the galactic globular cluster NGC 6266. Based on a comparison between the observed central surface brightness profiles of 38 globular clusters and state-of-the art N- body simulations, NGC 6266 offers the best hope of detecting an IMBH among these objects. This detection would be significant for at least two reasons. It would be the first concrete discovery of an IMBH, revealing unique information about the environment in which these objects form, and second, its discovery would provide a powerful validation on the N-body simulations used to track the dynamical evolution of globular clusters.
WFPC2 11083
The Structure, Formation and Evolution of Galactic Cores and Nuclei
A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS}, a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100 early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e., <0.1"-1"}, the HST brightness profiles vary systematically from the brightest giants {which have nearly constant surface brightness cores} to the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the fraction of galaxy mass contributed by the nuclei in the faint galaxies is identical to that contributed by supermassive black holes in the bright galaxies {0.2%}. These findings strongly suggest that a single mechanism is responsible for both types of Central Massive Object: most likely internally or externally modulated gas inflows that feed central black holes or lead to the formation of "nuclear star clusters". Understanding the history of gas accretion, star formation and chemical enrichment on subarcsecond scales has thus emerged as the single most pressing question in the study of nearby galactic nuclei, either active or quiescent. We propose an ambitious HST program {199 orbits} that constitutes the next, obvious step forward: high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging for the complete ACSVCS sample. By capitalizing on HST's unique ability to provide high-resolution images with a sharp and stable PSF at UV and IR wavelengths, we will leverage the existing optical HST data to obtain the most complete picture currently possible for the history of star formation and chemical enrichment on these small scales. Equally important, this program will lead to a significant improvement in the measured structural parameters and density distributions for the stellar nuclei and the underlying galaxies, and provide a sensitive measure of "frosting" by young stars in the galaxy cores. By virtue of its superb image quality and stable PSF, NICMOS is the sole instrument capable of the IR observations proposed here. In the case of the WFPC2 observations, high-resolution UV imaging {< 0.1"} is a capability unique to HST, yet one that could be lost at any time.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly Monitor
Intflat observations will be taken to provide a linearity check: the linearity test consists of a series of intflats in F555W, in each gain and each shutter. A combination of intflats, visflats, and earthflats will be used to check the repeatability of filter wheel motions. {Intflat sequences tied to decons, visits 1-18 in prop 10363, have been moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note: long-exposure WFPC2 intflats must be scheduled during ACS anneals to prevent stray light from the WFPC2 lamps from contaminating long ACS external exposures.
WFPC2 10916
A Study of SN Ejecta in the Core-Collapse Supernova Remnant G292.0+1.8: Cas A’s Older Cousin
Recent studies of the southern oxygen-rich supernova remnant {SNR} G292.0+1.8 have shown it to be the only Galactic SNR to exhibit all the features we expect in young remnants of core- collapse supernovae: an outer shell behind an expanding primary shock, high-velocity fragments of undiluted metal-rich ejecta, and a central pulsar surrounded by a pulsar-wind nebula. G292.0+1.8’s optical emission consists of numerous knots and filaments of O- and S-rich ejecta spread throughout much of the remnant shell, many with radially oriented pencil-like geometries that may trace their origins to Rayleigh-Taylor instabilities during the SN event. The evolution and fine-scale structure of SN debris in young remnants is poorly understood and largely uncharted territory. For testing models for the distribution of metal-rich ejecta from core-collapse SNe, how the ejecta evolve and clump, and how SN shocks interact with the local circumstellar medium, the 3000-yr-old G292.0+1.8 remnant rivals the 320-yr-old Cas A remnant in importance. We therefore propose the first HST images of G292.0+1.8 in order to characterize the fine-scale spatial distribution of the ejecta, their sub-arcsecond chemical make-up, and the detailed structure and scale lengths for metal-rich SN ejecta clumps. The proposed HST images of G292.0+1.8 will be used in conjunction with existing Spitzer Cycle 1 infrared data and an upcoming 0.5 Msec Chandra X-ray image. We expect to achieve the same kind of results for G292 that have already been obtained for Cas A. High-resolution HST images of this remnant, combined with Spitzer and Chandra data and contrasted with a similar data set on Cas A, will provide superb multiwavelength benchmarks for both very young and older core-collapse SNRs.
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 24 24
FGS REacq 16 16
OBAD with Maneuver 78 78
SIGNIFICANT EVENTS:
Battery SOC Modifications Flash Report:
At approximately 2008/094 13:32 GMT (9:32 am local), BM SOC, SOC1, SOC2 and PSI Test Limits were successfully increased by 10Ah via OPS request 18220. Ground limits for the battery pressures and FSW SOC were also updated via OPS note 1682. EPS SEs observed the expected FSW SOC increase upon uplink of the new value. Nominal system performance was observed for the rest of the EPS system.
