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 i
mages.
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 M>1e10 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 z>6. 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)