NASA Hubble Space Telescope Daily Status Report #4400

Notice: Due to the conversion of some ACS WFC or HRC observations into WFPC2, or NICMOS observations after the loss of ACS CCD science
capability in January, there may be an occasional discrepancy between a
proposal’s listed (and correct) instrument usage and the abstract that
follows it.
HUBBLE SPACE TELESCOPE DAILY REPORT # 4400
– Continuing to collect World Class Science
PERIOD COVERED: UT July 9, 2007 (DOY 190)
OBSERVATIONS SCHEDULED
ACS/SBC 10872
Lyman Continuum Emission in Galaxies at z=3D1.2
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=3D0.1 and z=3D2. 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=3D30 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=3D1.3, 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.
WFPC2 11024
WFPC2 CYCLE 15 INTERNAL MONITOR
This calibration proposal is the Cycle 15 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A variety
of internal exposures are obtained in order to provide a monitor of the
integrity of the CCD camera electronics in both bays {both gain 7 and
gain 15 — to test stability of gains and bias levels}, a test for
quantum efficiency in the CCDs, and a monitor for possible buildup of
contaminants on the CCD windows. These also provide raw data for
generating annual super-bias reference files for the calibration
pipeline.
ACS/SBC 10920
High-Resolution Imaging of Nearby Lyman Break Galaxy Analogs in the
GALEX All-Sky Survey
We have used the ultraviolet all-sky imaging survey currently being
conducted by the Galaxy Evolution Explorer {GALEX} to identify for the
first time a rare population of low-redshift starbursts with properties
remarkably similar to high-redshift Lyman Break Galaxies. These compact
UV luminous galaxies {UVLGs} resemble Lyman Break Galaxies in terms of
size, UV luminosity, star-formation rate, surface brightness, mass,
metallicity, kinematics, dust content, and color. They have
characteristic “ages” {stellar mass/SFR} of only a few hundred Myr.
This population of galaxies is thus worthy of study in its own right and
as a sample of local analogs of Lyman Break Galaxies. We propose to
image a sample of the 9 nearest and brightest compact UVLGs in the
near-ultraviolet, near-infrared, and H-alpha using ACS. With these
images we will 1} characterize their structure and morphology, 2} look
for signs of interactions and mergers, 3} investigate the distribution
and propagation of star formation over varying time scales, and 4}
quantify the stellar populations and star formation history, in order to
determine whether a previous generation of stars formed long before the
current burst. These data will perfectly complement our existing
Spitzer, GALEX, and SDSS data, and will provide important information on
star-formation in the present-day universe as well as shed light on the
earliest major episodes of star formation in high-redshift galaxies.
NICMOS 8791
NICMOS Post-SAA calibration – CR Persistence Part 2
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=3Ddate/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 11023
WFPC2 CYCLE 15 Standard Darks – part 1
This dark calibration program obtains dark frames every week in order to
provide data for the ongoing calibration of the CCD dark current rate,
and to monitor and characterize the evolution of hot pixels. Over an
extended period these data will also provide a monitor of radiation
damage to the CCDs.
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 individual
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 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 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 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.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARS:
#10884 GSAcq(2,1,2) failed to RGA Hold (Gyro Control).
Upon acquisition of signal (AOS) at 190/15:59:30, the GSAcq(2,1,2)
scheduled at 190/15:51:38 – 15:59:43 had failed to RGA Hold due to a
Search Radius Limit Exceeded Error on FGS-2. Pre-acquisition OBAD1 attitude
correction value not available due to LOS. OBAD2 had (RSS) value of 122.17
arcseconds. Post-acq OBAD/MAP (without maneuver) not scheduled.
SCHEDULED SUCCESSFUL FGS GSacq 8 7 FGS REacq 6 6 OBAD with Maneuver 28 28
COMPLETED OPS NOTES: (None)
SIGNIFICANT EVENTS: (None)