Status Report

NASA Hubble Space Telescope Daily Status Report #4336

By SpaceRef Editor
April 10, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Status Report #4336

Notice: For the foreseeable future, the daily reports may contain apparent discrepancies between some proposal descriptions and the listed instrument usage. This is due to the conversion of previously approved ACS WFC or HRC observations into WFPC2, or NICMOS observations subsequent to the loss of ACS CCD science capability in late January.


– Continuing to collect World Class Science

PERIOD COVERED: UT April 07,08,09, 2007 (DOY 096,097,098)


NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration – CR Persistence Part 6

A new proceedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and everytime 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 i mages. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive Galaxies, Galaxies Beyond

Deep near-infrared imaging provides the only avenue towards understanding a host of astrophysical problems, including: finding galaxies and AGN at z > 7, the evolution of the most massive galaxies, the triggering of star formation in dusty galaxies, and revealing properties of obscured AGN. As such, we propose to observe 60 selected areas of the GOODS North and South fields with NICMOS Camera 3 in the F160W band pointed at known massive M > 10^11 M_0 galaxies at z > 2 discovered through deep Spitzer imaging. The depth we will reach {26.5 AB at 5 sigma} in H_160 allows us to study the internal properties of these galaxies, including their sizes and morphologies, and to understand how scaling relations such as the Kormendy relationship evolved. Although NIC3 is out of focus and undersampled, it is currently our best opportunity to study these galaxies, while also sampling enough area to perform a general NIR survey 1/3 the size of an ACS GOODS field. These data will be a significant resource, invaluable for many other science goals, including discovering high redshift galaxies at z > 7, the evolution of galaxies onto the Hubble sequence, as well as examining obscured AGN and dusty star formation at z > 1.5. The GOODS fields are the natural location for HST to perform a deep NICMOS imaging program, as extensive data from space and ground based observatories such as Chandra, GALEX, Spitzer, NOAO, Keck, Subaru, VLT, JCMT, and the VLA are currently available for these regions. Deep high-resolution near-infrared observations are the one missing ingredient to this survey, filling in an important gap to create the deepest, largest, and most uniform data set for studying the faint and distant universe. The importance of these images will increase with time as new facilities come on line, most notably WFC3 and ALMA, and for the planning of future JWST observations.

WFPC2 11079

Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys

We propose to use WFPC2 to image the most interesting star-forming regions in the Local Group galaxies, to resolve their young stellar populations. We will use a set of filters including F170W, which is critical to detect and characterize the most massive stars, to whose hot temperatures colors at longer wavelengths are not sensitive. WFPC2’s field of view ideally matches the typical size of the star-forming regions, and its spatial resolution allows us to measure indvidual stars, given the proximity of these galaxies. The resulting H- R diagrams will enable studies of star-formation properties in these regions, which cover largely differing metallicities {a factor of 17, compared to the factor of 4 explored so far} and characteristics. The results will further our understanding of the star-formation process, of the interplay between massive stars and environment, the properties of dust, and will provide the key to interpret integrated measurements of star-formation indicators {UV, IR, Halpha} available for several hundreds more distant galaxies. Our recent deep surveys of these galaxies with GALEX {FUV, NUV} and ground-based imaging {UBVRI, Halpha, [OIII] and [SII]} provided the identification of the most relevant SF sites. In addition to our scientific analysis, we will provide catalogs of HST photometry in 6 bands, matched corollary ground-based data, and UV, Halpha and IR integrated measurements of the associations, for comparison of integrated star-formation indices to the resolved populations. We envisage an EPO component.

WFPC2 11022

WFPC2 Cycle 15 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check.

FGS 10989

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric elements {perturbation orbit semi-major axis and inclination} of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information {McArthur et al. 2004}, allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.

WFPC2 10890

Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies

The formative phase of the most massive galaxies may be extremely luminous, characterized by intense star- and AGN-formation. Till now, few such galaxies have been unambiguously identified at high redshift, restricting us to the study of low-redshift ultraluminous infrared galaxies as possible analogs. We have recently discovered a sample of objects which may indeed represent this early phase in galaxy formation, and are undertaking an extensive multiwavelength study of this population. These objects are bright at mid-IR wavelengths {F[24um]>0.8mJy}, but deep ground based imaging suggests extremely faint {and in some cases extended} optical counterparts {R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5, suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain deep ACS F814W and NIC2 F160W images of these sources and their environs in order to determine kpc-scale morphologies and surface photometry for these galaxies. The proposed observations will help us determine whether these extreme objects are merging systems, massive obscured starbursts {with obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted by intrinsically low-luminosity galaxies.

WFPC2 10886

The Sloan Lens ACS Survey: Towards 100 New Strong Lenses

As a continuation of the highly successful Sloan Lens ACS {SLACS} Survey for new strong gravitational lenses, we propose one orbit of ACS-WFC F814W imaging for each of 50 high-probability strong galaxy-galaxy lens candidates. These observations will confirm new lens systems and permit immediate and accurate photometry, shape measurement, and mass modeling of the lens galaxies. The lenses delivered by the SLACS Survey all show extended source structure, furnishing more constraints on the projected lens potential than lensed-quasar image positions. In addition, SLACS lenses have lens galaxies that are much brighter than their lensed sources, facilitating detailed photometric and dynamical observation of the former. When confirmed lenses from this proposal are combined with lenses discovered by SLACS in Cycles 13 and 14, we expect the final SLACS lens sample to number 80–100: an approximate doubling of the number of known galaxy-scale strong gravitational lenses and an order-of-magnitude increase in the number of optical Einstein rings. By virtue of its homogeneous selection and sheer size, the SLACS sample will allow an unprecedented exploration of the mass structure of the early-type galaxy population as a function of all other observable quantities. This new sample will be a valuable resource to the astronomical community by enabling qualitatively new strong lensing science, and as such we will waive all but a short {3-month} proprietary period on the observations.

WFPC2 10880

The host galaxies of QSO2s: AGN feeding and evolution at high luminosities

Now that the presence of supermassive black holes in the nuclei of galaxies is a well established fact, other questions related to the AGN phenomena still have to be answered. Problems of particular interest are how the AGN gets fed, how the black hole evolves and how the evolution of the black hole is related to the evolution of the galaxy bulge. Here we propose to address some of these issues using ACS/WFC + F775W snapshot images of 73 QSO2s with redshifts in the range 0.3< z< 0.4. These observations will be combined with similar archival data of QSO1s and ground based data of Seyfert and normal galaxies. First, we will intestigate whether interactions are the most important feeding mechanism in high luminosity AGNs. This will be done in a quantitative way, comparing the asymmetry indices of QSO2 hosts with those of lower luminosity AGNs and normal galaxies. Second, we will do a detailed study of the morphology of the host galaxies of both QSO types, to determine if they are similar, or if there is an evolutionary trend from QSO2s to QSO1s. The results from this project will represent an important step in the understanding of AGN evolution, and may also introduce a substantial modification to the Unified Model.

ACS/SBC 10872

Lyman Continuum Emission in Galaxies at z=1.2

Lyman continuum photons produced in massive starbursts may have played a dominant role in the reionization of the Universe. Starbursts are important contributors to the ionizing metagalactic background at lower redshifts as well. However, their contribution to the background depends upon the fraction of ionizing radiation that escapes from the intrinsic opacity of galaxies below the Lyman limit. Current surveys suggest escape fractions of a few percent, up to 10%, with very few detections {as opposed to upper limits} having been reported. No detections have been reported in the epochs between z=0.1 and z=2. We propose to measure the fraction of escaping Lyman continuum radiation from 15 luminous z~1.2 galaxies in the GOODS fields. Using the tremendous sensitivity of the ACS Solar- blind Channel, we will reach AB=30 mag., allowing us to detect an escape fraction of 1%. We will correlate the amount of escaping radiation with the photometric and morphological properties of the galaxies. A non-detection in all sources would imply that QSOs provide the overwhelming majority of ionizing radiation at z=1.3, and it would strongly indicate that the properties of galaxies at higher redshift have to be significantly different for galaxies to dominate reionization. The deep FUV images will also be useful for extending the FUV study of other galaxies in the GOODS fields.

NIC1 10859

Precise Measurements of Sgr A* Flare Activity

Correlated X-ray and near-IR flare emission from Sgr A*, the closest supermassive black hole, contains information about the hydrodynamics, energetics, and accretion behavior of matter within the innermost ten Schwarzschild radii of the hole. We propose HST/NICMOS observations of near-IR flares, in conjunction with already approved obsrevations using XMM-Newton {214 ksec} and CSO {3 nights}, which can make the precise, new measurements necessary to understand the radiation mechanism and low luminosity of Sgr A*. HST/NICMOS is required due to its very low and stable background, and its stable, tightly focused PSF, which allow accurate measurement of fainter flares than can be observed using groundbased adaptive optics systems. We will measure the spectral index distribution, the time-averaged flux and duration of flares, and the statistics of flare activity, and will confirm previously reported quasi-periodic variability. These measurements will have far-reaching implications for testing the inverse Compton scattering {ICS} and synchrotron models of low-luminosity flares, for understanding the process of accretion onto and outflow from supermassive black holes, and for constraining the acceleration mechanism of flares and the inferred black hole spin. This knowledge, in turn, will help us understand more generally low-luminosity AGN and X-ray binaries in a very low/quiescent accretion state.

WFPC2 10786

Rotational state and composition of Pluto’s outer satellites

We propose an intricate set of observations aimed at discovering the rotational state of the newly discovered satellites of Pluto, S/2005 P1 and S/2005 P2. These observations will indicate if the satellites are in synchronous rotation or not. If they are not, then the observations will determine the rotational period or provide tight constraints on the amplitude. The other primary goal is to extend the wavelength coverage of the colors of the surface and allow us to constrain the surface compositions of both objects. From these data we will also be able to significantly improve the orbits of P1 and P2, improve the measurement of the bulk density of Charon, and search for albedo changes on the surface of Pluto.

NIC2 10599

Multi-color imaging of two 1 Gyr old debris disks within 20 pc of the Sun: Astrophysical mirrors of our Kuiper Belt

We report the first scattered light detections of two debris disk around an F star and a K star using optical coronagraphy and the Hubble Space Telescope. With ages ~1 Gyr, these are the oldest debris disks thus far seen in the optical. We propose deep, multi-roll angle coronagraphic imaging with HST ACS and NICMOS to confirm and characterize the disks in terms of structure and composition. The disks appear to have belt-like morphology that is consistent with the existence of planetary companions or other perturbing bodies. Since these disks are close to our Kuiper Belt in an evolutionary context, detailed understanding of their mass, structure and composition will provide a fresh perspective for inferring the history and properties of our own trans-Neptunian region.


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


10769 – GSAcq (1,2,2) failed to RGA control

At AOS 096/10:05:16 GSAcq (1,2,2) scheduled from 096/08:38:21-08:45:41 had failed to RGA control (Gyro Hold) due to QSTOP flag on FGS 1.

OBAD MAP: V1 107.01, V2 -402.65, V3 -335.62, RSS 535.02

(This failure occurred during an LOS in the previous reporting period @ 096/08:38:21z, and so is not counted as a failure for this reporting period.)

10770 – GSAcq(1,3,3) failed to RGA Hold (Gyro Control)

Upon acquisition of signal at 098/19:24:30, the GSAcq(1,3,3) scheduled at 098/19:15:04 – 19:23:09 had failed to RGA Hold due to (QF1STOPF) stop flag indication on FGS1. Pre-acquisition OBADs (RSS) attitude correction values not available due to LOS. Post-acq OBAD/MAP had (RSS) value of 18.13 arcseconds.



                        SCHEDULED      SUCCESSFUL 

FGS GSacq                27                  26 
FGS REacq                10                   10 
OBAD with Maneuver       76                   76 


SpaceRef staff editor.