Status Report

NASA Hubble Space Telescope Daily Report # 4602

By SpaceRef Editor
May 5, 2008
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NASA Hubble Space Telescope Daily Report # 4602
NASA Hubble Space Telescope Daily Report # 4601


Continuing to collect World Class Science

PERIOD COVERED: 5am May 01 – 5am May 02, 2008 (DOY 122/0900z – 123/0900z)


ACS/SBC 11200

An Ultraluminous EUV Source?

Ultraluminous X-ray sources (ULXs) are bright, irregularly variable, non-nuclear, X- ray sources with apparent luminosities exceeding the Eddington limit for stellar- mass black holes. There is great interest in ULXs because they may represent a new class of black holes with masses intermediate between stellar-mass and supermassive black holes. Recently, it has been found that X-ray emission from the nebula MF 16 in the galaxy NGC 6946, previously thought to be an usually luminous supernova remnant, actually arises from an accreting compact object. Optical spectroscopy of nebula shows that it is powered via photoionization by an extreme ultraviolet (EUV) source with a luminosity exceeding that measured from the X-ray source. If correct this would be the first ultraluminous UV source and may be a 10, 000 solar mass black hole. We propose an FUV observation with the ACS/SBC to determine if a highly luminous EUV source is indeed, present within MF 16.

NIC1 11136

Resolving Ultracool Astrophysics with Brown Dwarf Binaries

We propose to obtain resolved far-red and near-IR photometry of 13 brown dwarf binaries with HST/NICMOS in order to study one of the long-standing puzzles in ultracool astrophysics, namely the rapid change in spectra from L dwarfs to T dwarfs at nearly constant effective temperature (a.k.a. the “L/T transition”). While many nearby brown dwarfs have been studied, use of such samples is inevitably hindered by the unknown ages, masses, and metallicities of the field population. Characterization of resolved ultracool binaries is a promising avenue for addressing this problem, by providing coeval systems of the same composition with comparable masses and temperatures. Our proposed HST/NICMOS (0.9-1.6 micron) observations will be combined with longer wavelength ground-based photometry and spectroscopy from Keck laser guide star adaptive optics. The resulting multiband (0.9-2.5 micron) dataset will be a unique resource for measuring the evolution of spectral energy distributions across the L/T transition, to test state-of-the-art atmospheric models, and to determine the physical process(es) that dominate the L/T transition. Understanding the L/T transition is important not only for testing brown dwarf atmospheres, but also provides a key pathway for understanding the same physical effects, namely the formation and removal of clouds, in the atmospheres of the extrasolar planets.

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.

NIC2/NIC1/NIC3 11159

The True Galactic Bulge Luminosity Function

We propose to obtain second epoch imaging of the deep Galactic bulge field observed using NICMOS by Zoccali et al. (2000). The bulge luminosity and mass function suffered from 30-50% contamination by foreground disk stars, which was impossible to correct for in the original study. Revisiting the field after 9 years, we propose to segregate the foreground disk stars because they have large transverse velocities, thus revealing the luminosity function of Galactic bulge low mass stars to near the hydrogen burning limit. The slope of the mass function has implications for galaxy formation and for understanding the nature of microlensing in the Galactic bulge.

NIC3 11332

NICMOS Cycle 16 Time Dependent Flat Fields

This proposal obtains sequences of NICMOS narrow, medium and broad band filter flat fields for camera 1. In cameras 2 and 3, parallel observations will allow us to obtain high S/N flats for all spectral elements.

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.

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.

WFPC2 11027

Visible Earth Flats

This proposal monitors flatfield stability. This proposal obtains sequences of Earth streak flats to construct high quality flat fields for the WFPC2 filter set. These flat fields will allow mapping of the OTA illumination pattern and will be used in conjunction with previous internal and external flats to generate new pipeline superflats. These Earth flats will complement the Earth flat data obtained during cycles 4-14.

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 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 11178

Probing Solar System History with Orbits, Masses, and Colors of Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens a window into dynamical conditions in the protoplanetary disk where they formed as well as the history of subsequent events which sculpted the outer Solar System and emplaced them onto their present day heliocentric orbits. To date, at least 47 TNBs have been discovered, but only about a dozen have had their mutual orbits and separate colors determined, frustrating their use to investigate numerous important scientific questions. The current shortage of data especially cripples scientific investigations requiring statistical comparisons among the ensemble characteristics. We propose to obtain sufficient astrometry and photometry of 23 TNBs to compute their mutual orbits and system masses and to determine separate primary and secondary colors, roughly tripling the sample for which this information is known, as well as extending it to include systems of two near-equal size bodies. To make the most efficient possible use of HST, we will use a Monte Carlo technique to optimally schedule our observations.

WFPC2 11316

HST Cycle 16 & pre-SM4 Optical Monitor

This is a continuation of the Cycle 15 & pre-SM4 Optical Monitor, 11020. Please see that proposal for a more complete description of the observing strategy. The 6 visits comprising this proposal observe two single standard stars with WFPC2/PC in order to establish overall OTA focal length for the purposes of focus maintenance. The goal of this monitoring before SM4 is to establish a best estimate of the OTA focus entering SMOV.


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

HSTARS: (None)



                       SCHEDULED      SUCCESSFUL

FGS GSacq                09                  09
FGS REacq                06                  06
OBAD with Maneuver       30                  30


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