HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4650

PERIOD COVERED: 5am July 10 - 5am July 11, 2008 (DOY192/0900z-193/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC 11151

Evaluating the Role of Photoevaporation of Protoplanetary Disk Dispersal

Emission produced by accretion onto the central star leads to
photoevaporation, which may play a fundamental role in disk dispersal.
Models of disk photoevaporation by the central star are challenged by
two potential problems: the emission produced by accretion will be
substantially weaker for low-mass stars, and photoevaporation must
continue as accretion slows. Existing FUV spectra of CTTSs are biased to
solar-mass stars with high accretion rates, and are therefore
insufficient to address these problems. We propose use HST/ACS SBC
PR130L to obtain FUV spectra of WTTSs and of CTTSs at low masses and
mass accretion rates to provide crucial data to evaluate
photoevaporation models. We will estimate the FUV and EUV luminosities
of low-mass CTTSs with small mass accretion rates, CTTSs with transition
disks and slowed accretion, and of magnetically-active WTTSs.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic O
Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long term
spectroscopic and high angular resolution observations to determine
their masses and distances. The results will also be important for the
interpretation of the spectra of suspected and newly identified binary
and multiple systems.

FGS 11214

HST/FGS Astrometric Search for Young Planets Around Beta Pic and AU Mic

Beta Pic and AU Mic are two nearby Vega-type debris disk stars. Both of
these disk systems have been spatially resolved in exquisite detail,
predominantly via the ACS coronagraph and WFPC-2 cameras onboard HST.
These images exhibit a wealth of morphological features which provide
compelling indirect evidence that these systems likely harbor
short-period planetary body{ies}. We propose to use the superlative
astrometric capabilities of HST/FGS to directly detect these planets,
hence provide the first direct planet detection in a Vega-type system
whose disk has been imaged at high spatial resolution.

NIC1/NIC2/NIC3 11318

NICMOS Cycle 16 Multiaccum Darks

The purpose of this proposal is to monitor the dark current, read noise,
and shading profile for all three NICMOS detectors throughout the
duration of Cycle 16. This proposal is a slightly modified version of
proposal 10380 of cycle 13 and 9993 of cycle12 and is the same as Cycle
15. Covers the period from April 08 to November 08 (inclusive)

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

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 i
mages. Each observation will need its own CRMAP, as different SAA
passages leave different imprints on the NICMOS detectors.

NIC2 11799

NICMOS Non-linearity Calibration for Faint Objects

NICMOS has played a key role in probing the deep near infrared regime
for a decade. It has been the only instrument available to observe
objects in the near infrared that are not visible from the ground. In
particular, it has played a major role in the SN Ia observations at
redshifts z>1. However, the calibration of NICMOS has turned out to be
difficult due to the apparent non-linearity of the detectors. The NICMOS
calibration team has described the non-linearity as a power law based on
data in the range of ~50-5000 ADU/s. The correction relies on an
extrapolation of two orders of magnitude in flux at count rates close to
the sky level (0.1 ADU/s) where space observations are particularly
prized - and where SN Ia observations are made. Precise measurements of
faint objects require us to reduce the uncertainties from this
extrapolation. Here we propose to derive the absolute calibration in the
sky limited regime and to characterize the non-linearity over the entire
dynamic range for the camera/filter combination: NIC2/F110W.

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 11167

A Unique High Resolution Window to Two Strongly Lensed Lyman Break
Galaxies

On rare occasions, the otherwise very faint Lyman Break Galaxies {LBGs}
are magnified by gravitational lensing to provide exceptional targets
for detailed spectroscopic and imaging studies. We propose HST WFPC2 and
NICMOS imaging of two strongly lensed Lyman Break Galaxies {LBGs} that
were recently discovered by members of our team. These two LBGs -- the
"8 O'Clock Arc" and the "SDSS J1206+5142 Arc" -- are currently the
brightest known LBGs, roughly 3 times brighter than the former
record-holder, MS1512-cB58 {a.k.a. "cB58"}. The z=2.73 "8 O'Clock Arc"
extends ~10 arcsec in length and is magnified by a factor of 12. The
z=2.00 "SDSS J1206+5142 Arc" also extends ~10 arcsec in length and is
magnified by a factor of 30. Due to their brightness and magnification,
these two strongly lensed LBGs offer an unprecedented opportunity for
the very detailed investigation of two individual galaxies at high
redshift. We are currently pursuing a vigorous ground-based campaign to
obtain multi- wavelength {UV, optical, NIR, radio} observations of these
two LBGs, but our campaign currently lacks a means of obtaining
high-resolution optical/NIR imaging -- a lack that currently only HST
can address. Our prime objective for this proposal is to obtain high
resolution HST images of these two systems with two-orbit WFPC2 images
in the BVI bands and two-orbit NICMOS/NIC2 images in the J and H bands.
These data will allow us to construct detailed lensing models, probe the
mass and light profiles of the lenses and their environments, and
constrain the star formation histories and rest-frame UV/optical
spectral energy distributions of the LBGs.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:
#11384 REacq(1,2,2) failed to RGA control @ 193/02:33z.
REacq(1,2,2) scheduled at 193/02:30:57z failed to RGA control at
02:33:51z. Stop flags QF1STOPF and QSTOP were received for FGS 1.
There were no other flags or ESB messages.   
Observations affected: WFPC 101 -102 Proposal ID#11167, NIC 167
Proposal ID#11330.

#11385 GSacq(1,2,1) failed due to search radius limit exceeded @193/06:56z.
During LOS, GSacq(1,2,1) scheduled at 193/06:56:46z failed due to
search radius limit exceeded on FGS 1. ESB message "a05" (FGS Coarse
Tract failed - search Radius Limit exceeded) was received.
Observations affected:  WFPC 103-105, Proposal ID #11142.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                               SCHEDULED     SUCCESSFUL      
FGS GSacq                        5                    4       
FGS REacq                        7                    6
OBAD with Maneuver         24                  24  

SIGNIFICANT EVENTS: (None)