Daily Report #4638

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4638

PERIOD COVERED: 5am June 23 - 5am June 24, 2008 (DOY 175/0900z-176/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC 11110

Searching for Lyman Apha Emission from FUSE Lyman Continuum Candidates

We have recently been granted time on FUSE to characterize the escape
fraction of hydrogen Lyman continuum (Lyc) photons from a morphologically
diverse set of star forming galaxies. The FUSE program is designed to
provide ~ 5 sigma detections of Lyc photons emitted from star forming
galaxies with escape fractions ~5%. With this proposal we seek hydrogen
Lyman alpha (Lya) observations of a representative subset of the FUSE
program targets to constrain the observational relationship between Lyc,
Lya, and hydrogen Balmer line emission in these systems. Such observations
explore the detailed balance between the simple optically thin (Case A) and
optically thick (Case B) limits in recombination theory. The ultimate goal
of this program is to quantify the relationship between escaping Lya and Lyc
emission and the first structures that form in the early universe.

ACS/SBC 11131

Star Formation at Large Radii in Cooling Flow Brightest Cluster Galaxies

We propose to take deep ACS FUV images of the bright central galaxies in two
powerful cooling flow clusters for which we have VLT UBR images, with the
object of determining whether the UV excesses we observe at large radii
(15kpc) are caused by young stars, ultrahot (WR) stars, or an as yet
unknown source. Current models of excess UV light at the AGN-dominated
centers of these galaxies cannot easily be extended to large radii. New
understanding of star formation in these clusters will be directly
applicable to scenarios of galaxy formation in the early universe.

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.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary system
architecture as yet untested by direct observation for main sequence stars
other than the Sun. To provide such a test, we propose to carry out FGS
astrometric studies on four stars hosting seven companions. Our
understanding of the planet formation process will grow as we match not only
system architecture, but formed planet mass and true distance from the
primary with host star characteristics for a wide variety of host stars and
exoplanet masses. We propose that a series of FGS astrometric observations
with demonstrated 1 millisecond of arc per-observation precision can
establish the degree of coplanarity and component true masses for four
extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311
{planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB =
gamma Cephei {planet+star}. In each case the companion is identified as such
by assuming that the minimum mass is the actual mass. For the last target, a
known stellar binary system, the companion orbit is stable only if coplanar
with the AB binary orbit.

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

WFPC2 11070

WFPC2 CYCLE 15 Standard Darks - part II

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 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.

NIC3/WFPC2 11192

NICMOS Confirmation of Candidates of the Most Luminous Galaxies at z 7

While the deepest pencil-beam near-IR survey suggested that the Universe was
too young to build up many luminous galaxies by z ~ 7--8 (Bouwens &
Illingworth 2006), there is also evidenc indicating the contrary. It is now
known that some galaxies with stellar masses of M1e10 Msun were already in
place by z ~ 6--7, which strongly suggests that their progenitors should be
significantly more luminous, and hence detectable in deep, wide-field
near-IR surveys (Yan et al. 2006). As galaxies at such a high redshift
should manifest themselves as "dropouts" from the optical, we have carried
out a very wide-field, deep near-IR survey in the GOODS fields to search for
z-band dropouts as candidates of galaxies at z 7. In total, six promising
candidates have been found in ~ 300 sq. arcmin to J_AB ~ 24.5 mag
(corresponding to restframe M(UV) -22.5 mag at z ~ 7). By contrast, the
galaxy luminosity function (LF) suggested in BI06 would predict at most 3--5
galaxies over the entire 2-pi sky at this brightness level. Here we propose
to observe these candidates with NIC3 in F110W and F160W to further
investigate their nature. If any of these candidates are indeed at z 7,
the result will lead to a completely new picture of star formation in the
early universe. If none of our candidates are consistent with being at z
7, then the depth and area of our near-IR survey (from which the candidates
are drawn) will let us set a very stringent upper limit on the bright end of
the galaxy LF at those redshift. As a result, our program will still be able
to provide new clues about the processes of early galaxy formation, such as
their dust contents and their merging time scale (Yan et al. 2006).

WFPC2/NIC3 11188

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for
reionization of the universe at z6. However, the models that attempt to
describe the detailed impact of high- redshift galaxies on the surrounding
inter-galactic medium {IGM} are strongly dependent upon several uncertain
parameters. Perhaps the most uncertain is the fraction of HI-ionizing
photons produced by young stars which escape into the IGM. Most attempts to
measure this "escape fraction" {f_esc} have produced null results. Recently,
a small subset of z~3 Lyman Break Galaxies {LBGs} has been found exhibiting
large escape fractions. It remains unclear however, what differentiates them
from other LBGs. Several models attempt to explain how such a large fraction
of ionizing continuum can escape through the HI and dust in the ISM {eg.
"chimneys" created by SNe winds, globular cluster formation, etc.}, each
producing unique signatures which can be observed with resolved imaging of
the escaping Lyman continuum. We propose a deep, high resolution WFPC2 image
of the ionizing continuum {F336W} and the rest-frame 1500 Angstrom continuum
{F606W} of five of the six known LBGs with large escape fractions. These
LBGs all fit within a single WFPC2 pointing, yielding high observing
efficiency. Additionally, they all have z~3.1 or higher, the optimal
redshift range for probing the Lyman Continuum region with available WFPC2
filters. These factors make our proposed sample especially suitable for
follow- up. With these data we will discern the mechanisms responsible for
producing large escape fractions, and therefore gain insight into the
process of reionization.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11351 - REacq(2,1,1) failed to RGA Hold (Gyro Control)

REacq(2,1,1) scheduled at 176/03:16:08 - 03:24:13 failed to RGA Hold due to
stop flag (QF2STOPF) indication on FGS-2. Pre-acquisition OBADs had attitude
corrections (RSS) values of 19.65 and 1.46 arcseconds. Post-acq OBAD/MAP had
3-axis (RSS) error of 2671.54 arcseconds. Prior guide star acquisition at
176/01:44:02 was successful.

Possible Observations affected: WFPC 79 thru 81 Proposal ID#11192, NICMOS 93
same Proposal ID#11192.

Upon acquisition of signal at 176/05:25:15, the REacq(2,1,1) scheduled at
176/04:52:53 had failed to RGA Hold with stop flag (QF2STOPF) indication on
FGS-2. Pre-acq OBADs attitude correction values are not available due to
LOS.

Possible Observations affected: WFPC 82 thru 84 Proposal ID#11192

Upon acquisition of signal at 176/08:04:46, the REacq(2,1,1) scheduled at
176/06:28:47 had failed to RGA Hold due to stop flag (QF2STOPF) indication
on FGS-2. Pre-acq OBAD1 (RSS) value is not available due to LOS. Pre-acq
OBAD2 had (RSS) value of 14.20 arcseconds.

Possible Observations affected: WFPC 85 thru 87 Proposal ID#11192, NICMOS
same Proposal ID#11192.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 07 07
FGS REacq 07 04
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)