Status Report

NASA Hubble Space Telescope Daily Report #4775

By SpaceRef Editor
January 22, 2009
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Continuing to collect World Class Science

PERIOD COVERED: 5am January 21 – 5am January 22, 2009 (DOY 021/1000z-022/1000z)


WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz < 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a snapshot imaging survey of the sites of some of these nearby objects, to obtain late-time photometry that {through the shape of the light and color curves} will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-color and color-magnitude diagrams of stars in these SN sites, to determine the SN progenitor masses and constraints on the reddening. Recovery of the SNe in the new HST images will also allow us to actually pinpoint their progenitor stars in cases where pre- explosion images exist in the HST archive. This proposal is an extension of our successful Cycle 13 snapshot survey with ACS. It is complementary to our Cycle 15 archival proposal, which is a continuation of our long-standing program to use existing HST images to glean information about SN environments.

FGS 11964

Post FGS1r AMA-Adjustment: OFAD Check and Alignment Calibration, 2008

The FGS1 AMA optimization proposal (11963) leaves the AMA mirror in a new position, which shifts the FGS1r FOV relative to FGS2r and FGS3 and has the potential to change the FGS1r OFAD solution. This proposal will use the astrometric open cluster NGC 5617 to check for 1 mas size changes in the OFAD and to establish the new alignment of FGS1r relative to FGS2r and FGS3 to a precision of approximately 25 mas. The OFAD check requires 4 HST orbits before, and 4 HST orbits after, the AMA adjustment. Each orbit observes the same stars in NGC 5617 with FGS1r in POS mode. The alignment aspect of this proposal uses data from these same orbits. The ICRS positions of the relevant stars are taken from the UCAC catalog, but the proper motions taken from the “special guide star plate ZZZT” provided by Yale University. We chose guide stars in FGS2r and FGS3, and astrometry targets that are common to GSC2, UCAC, and ZZZT. Each visit uses a unique guide star pair, so that all the visits taken together have guide stars spanning the guider FGSs FOV.

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 11130

AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II

The recent progress in the study of central black holes in galactic nuclei has led to a general consensus that supermassive {10^6-10^9 solar mass} black holes are closely connected with the formation and evolutionary history of large galaxies, especially their bulge component. Two outstanding issues, however, remain unresolved. Can central black holes form in the absence of a bulge? And does the mass function of central black holes extend below 10^6 solar masses? Intermediate-mass black holes {<10^6 solar masses}, if they exist, may offer important clues to the nature of the seeds of supermassive black holes. Using the SDSS, our group has successfully uncovered a new population of AGNs with intermediate-mass black holes that reside in low-luminosity galaxies. However, very little is known about the detailed morphologies or structural parameters of the host galaxies themselves, including the crucial question of whether they have bulges or not. Surprisingly, the majority of the targets of our Cycle 14 pilot program have structural properties similar to dwarf elliptical galaxies. The statistics from this initial study, however, are really too sparse to reach definitive conclusions on this important new class of black holes. We wish to extend this study to a larger sample, by using the Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175 AGNs with intermediate- mass black holes selected from our final SDSS search. We are particularly keen to determine whether the hosts contain bulges, and if so, how the fundamental plane properties of the host depend on the mass of their central black holes. We will also investigate the environment of this unique class of AGNs.

WFPC2 11944

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint to observe using ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass – radius relation.

WFPC2 11969

Satellite Search for Dawn Mission Targets, Vesta and Ceres

We propose to carry out a dedicated satellite search program for asteroids Vesta and Ceres. Despite being the two largest asteroids, and having clear evidence of a violent collisional history for Vesta, Vesta and Ceres do not have any satellites found so far, neither have there been any dedicated satellite search program for them reported. We propose to take short and long exposure mosaics to cover the whole Hill sphere while using specific observing strategies and image processing techniques to search in close to the center body. In addition to its significant scientific merit, this proposed project will be important for the planning of NASA’s Dawn mission. Currently Ceres is moving close to the Earth, making it more difficult to cover the whole stability region of satellites with minimal HST orbit requirement. Similar geometry will not repeat until the second half of 2009. Therefore we request DD time.


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

HSTARS: (None)



                          SCHEDULED      SUCCESSFUL

FGS GSacq                 11                  11
FGS REacq                 0                    0
OBAD with Maneuver        24                  24


SpaceRef staff editor.