HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4647
PERIOD COVERED: 5am July 7 - 5am July 8, 2008 (DOY
189/0900z-190/0900z)
OBSERVATIONS SCHEDULED
ACS/SBC 11215
New Sightlines for the Study of Intergalactic Helium:
Dozens of
High-Confidence, UV-Bright Quasars from SDSS/GALEX
The reionization of IGM helium is thought to have occurred
at redshifts
of z=3 to 4. Detailed study of HeII Lyman-alpha absorption
toward a
handful of QSOs at 2.7<z<3.3 demonstrated the high
potential of such IGM
probes, but the critically small sample size limits
confidence in
cosmological inferences. The requisite unobscured
sightlines to high-z
are extremely rare, but SDSS provides 5800, z>3.1 QSOs
potentially
suitable for HeII studies. We've cross-correlated SDSS
quasars with
GALEX UV sources to obtain dozens of new, high confidence,
candidate
sightlines {z=3.1-4.9} potentially useful for detailed
HeII studies with
HST. We propose brief, 2- orbit reconnaissance ACS SBC
prism exposures
toward each of the best dozen new quasars, to definitively
verify UV
flux down to HeII. Our combined SDSS/GALEX selection
insures a high
confirmation rate, as the quasars are already known to be
UV bright in
GALEX. Our program will provide a statistical sample of
HeII sightlines
extending to high redshift, enabling future long exposure
follow-up
spectra with the SBC prism, or superb quality COS or STIS
spectra after
SM4. Stacks of our prism spectra will also directly yield
ensemble
information. Ultimately, the new sightlines will enable
confident
measures of the spectrum and evolution of the ionizing
background, the
evolution of HeII opacity, the epoch of helium
reionization, and the
density of IGM baryons.
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 11213
Distances to Eclipsing M Dwarf Binaries
We propose HST FGS observations to measure accurate
distances of 5
nearby M dwarf eclipsing binary systems, from which
model-independent
luminosities can be calculated. These objects have either
poor or no
existing parallax measurements. FGS parallax
determinations for these
systems, with their existing dynamic masses determined to
better than
0.5%, would serve as model-independent anchor points for
the low-mass
end of the mass-luminosity diagram.
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.
NIC3 11107
Imaging of Local Lyman Break Galaxy Analogs: New Clues to
Galaxy
Formation in the Early Universe
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
{LBGs}. These
"compact UV luminous galaxies" {UVLGs} resemble
LBGs in terms of size,
SFR, surface brightness, mass, metallicity, kinematics,
dust, and color.
The UVLG sample offers the unique opportunity of
investigating some very
important properties of LBGs that have remained virtually
inaccessible
at high redshift: their morphology and the mechanism that
drives their
star formation. Therefore, in Cycle 15 we have imaged 7
UVLGs using ACS
in order to 1} characterize their morphology and look for
signs of
interactions and mergers, and 2} probe their star
formation histories
over a variety of timescales. The images show a striking
trend of
small-scale mergers turning large amounts of gas into
vigorous
starbursts {a process referred to as dissipational or
"wet" merging}.
Here, we propose to complete our sample of 31 LBG analogs
using the
ACS/SBC F150LP {FUV} and WFPC2 F606W {R} filters in order
to create a
statistical sample to study the mechanism that triggers
star formation
in UVLGs and its implications for the nature of LBGs.
Specifically, we
will 1} study the trend between galaxy merging and SFR in
UVLGs, 2}
artificially redshift the FUV images to z=1-4 and compare
morphologies
with those in similarly sized samples of LBGs at the same
rest-frame
wavelengths in e.g. GOODS, UDF, and COSMOS, 3} determine
the presence
and morphology of significant stellar mass in
"pre-burst" stars, and 4}
study their immediate environment. Together with our
Spitzer
{IRAC+MIPS}, GALEX, SDSS and radio data, the HST
observations will form
a unique union of data that may for the first time shed
light on how the
earliest major episodes of star formation in high redshift
galaxies came
about. This proposal was adapted from an ACS HRC+WFC
proposal to meet
the new Cycle 16 observing constraints, and can be carried
out using the
ACS/SBC and WFPC2 without compromising our original
science goals.
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 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 11103
A Snapshot Survey of The Most Massive Clusters of Galaxies
We propose the continuation of our highly successful
SNAPshot survey of
a sample of 125 very X-ray luminous clusters in the
redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so
far in Cycle14
and Cycle15 these systems frequently exhibit strong
gravitational
lensing as well as spectacular examples of violent galaxy
interactions.
The proposed observations will provide important
constraints on the
cluster mass distributions, the physical nature of
galaxy-galaxy and
galaxy-gas interactions in cluster cores, and a set of
optically bright,
lensed galaxies for further 8-10m spectroscopy. All of our
primary
science goals require only the detection and
characterization of
high-surface-brightness features and are thus achievable
even at the
reduced sensitivity of WFPC2. Because of their high
redshift and thus
compact angular scale our target clusters are less
adversely affected by
the smaller field of view of WFPC2 than more nearby
systems.
Acknowledging the broad community interest in this sample
we waive our
data rights for these observations. Due to a clerical
error at STScI our
approved Cycle15 SNAP program was barred from execution
for 3 months and
only 6 observations have been performed to date -
reinstating this SNAP
at Cycle16 priority is of paramount importance to reach
meaningful
statistics.
WFPC2 11202
The Structure of Early-type Galaxies: 0.1-100 Effective
Radii
The structure, formation and evolution of early-type
galaxies is still
largely an open problem in cosmology: how does the
Universe evolve from
large linear scales dominated by dark matter to the highly
non-linear
scales of galaxies, where baryons and dark matter both
play important,
interacting, roles? To understand the complex physical
processes
involved in their formation scenario, and why they have
the tight
scaling relations that we observe today {e.g. the
Fundamental Plane}, it
is critically important not only to understand their
stellar structure,
but also their dark-matter distribution from the smallest
to the largest
scales. Over the last three years the SLACS collaboration
has developed
a toolbox to tackle these issues in a unique and
encompassing way by
combining new non-parametric strong lensing techniques,
stellar
dynamics, and most recently weak gravitational lensing,
with
high-quality Hubble Space Telescope imaging and VLT/Keck
spectroscopic
data of early-type lens systems. This allows us to break
degeneracies
that are inherent to each of these techniques separately
and probe the
mass structure of early-type galaxies from 0.1 to 100
effective radii.
The large dynamic range to which lensing is sensitive
allows us both to
probe the clumpy substructure of these galaxies, as well
as their
low-density outer haloes. These methods have convincingly
been
demonstrated, by our team, using smaller pilot-samples of
SLACS lens
systems with HST data. In this proposal, we request
observing time with
WFPC2 and NICMOS to observe 53 strong lens systems from
SLACS, to obtain
complete multi-color imaging for each system. This would
bring the total
number of SLACS lens systems to 87 with completed HST
imaging and
effectively doubles the known number of galaxy-scale
strong lenses. The
deep HST images enable us to fully exploit our new
techniques, beat down
low-number statistics, and probe the structure and
evolution of
early-type galaxies, not only with a uniform data-set an
order of
magnitude larger than what is available now, but also with
a fully
coherent and self-consistent methodological approach!
WFPC2 11206
At the Cradle of the Milky Way: Formation of the Most
Massive Field Disk
Galaxies at z>1
We propose to obtain 2 orbit WFPC2 F814W images of a
sample of the 15
most massive galaxies found at $1 < z < 1.3$. These
were culled from
over 20,000 Keck spectra collected as part of DEEP and are
unique among
high redshift massive galaxy samples in being
kinematically selected.
Through a recent HST NICMOS-2 imaging program {GO-10532},
we have
confirmed that these galaxies have regular stellar disks,
and their
emission line kinematics are not due to gradients from
merging
components. These potentially very young galaxies are
likely precursors
to massive local disks, assuming no further merging. The
proposed WFPC2
and existing NIC-2 data provide colors, stellar masses,
and ages of
bulge and disk subcomponents, to assess whether old
stellar bulges and
disks are in place at that time or still being built, and
constrain
their formation epochs. Finally, this sample will yield
the first
statistically significant results on the $z > 1$
evolution of the
size-velocity-luminosity scaling relations, for massive
galaxies at
different wavelengths, and constrain whether this
evolution reflects
stellar mass growth, or passive evolution, of either bulge
or disk
components.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
#11377 GSAcq(1,2,1) failed to RGA Hold (Gyro Control)
@189/10:12z.
Upon acquisition of signal at 189/11:12:01z, GSAcq(1,2,1)
scheduled at
189/10:06:33 - 10:14:38z was observed to have failed to
RGA Hold due
to search radius limit exceeded on FGS-1. ESB Dump (ROP
DF-18A) at
189/11:16:06z revealed one 486 ESB message "a05"
(FGS Coarse Track
failed - Search Radius Limit Exceeded) was received at
189/10:12:23z.
Pre-acquisition OBADs had (RSS) attitude error correction
values of
3635.30 and 110.00 arcseconds. Post-acq OBAD/MAP (without
maneuver)
had 3-axis error (RSS) value of 1228.25 arcseconds.
Subsequent REAcq
(1,2,1) at 189/11:41:07z was successful. Possible
Observations affected:
WFPC 23 thru 26, Proposal #ID11196.
#11379 Gyro 6 Motor Current Spike @
186/18:54z.
At 2008/186/18:54:23z, while in LOS, the Gyro 6 motor
current rose to
a maximum value of 313 milliamps, before recovering back
to its
pre-transient value of 184 milliamps at 18:55:05z. The
final G6 motor
current settled ~1 count below the pre-anomaly level. The
gyro 6 bad
disparity counter was seen to increment to 191 counts (4.775
seconds)
(12 second telemetry update rate). The safing test limit is
25 seconds.
Gyro 6 experienced its first rotor restriction (HSTAR 11313) at
2008/141/20:46:18z. This event caused the Loss of Lock documented
in
HSTAR 11374.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
9
8
FGS
REacq
4
4
OBAD with
Maneuver 26
26
SIGNIFICANT EVENTS: (None)
DOY 189 VTFE Curve Adjustment Flash Report
Improvements to the power system configuration have been
identified
in the form of a VTFE adjustment. Recent battery
temperature
performance indicates that the system would benefit from a
slightly
steeper VTFE slope without a ‘Dog Leg’.
At 189/1415 GMT, during an orbit night pass while OCA was
not in
progress, the VTFE curves for the batteries were
adjusted. Batteries
1, 2, 4-6 were set at K1L4-100mV with a slope of 80mV/degC
and