HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5177
PERIOD
COVERED: 5am September 8 - 5am September 9, 2010 (DOY 251/09:00z-252/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12384
- GSAcq(1,2,1) at 251/10:36:01 and REAcq(1,2,1) at 251/12:12:09z
and 251/13:48:00z all resulted in fine lock backup on FGS1.
Observations possibly affected: STIS 26-29 Proposal ID#11668 &
WFC3 74-75 Proposal ID#11912
12385
- REAcq(1,2,1) at 251/17:32:32z failed.
Observations affected: COS 70-72 Proposal ID#11535; WFC3 76-77
Proposal ID#11914
12387
- GSAcq(1,2,1) at 252/05:38:36z Fails to RGA Hold, Search radius Limit Exceeded
on FGS1.
Observations affected: ACS36-39 Proposal ID#12292
HSTAR
FOR DOY 235
12386
- GSAcq(1,2,1) at 235/15:57:36 required three attempts to achieve
CT-DV on FGS1. The acquisition was successful.
Observations possibly affected: STIS 11-13 Proposal ID#11847; COS
15
Proposal ID#11895; WFC3 9 Proposal ID#11638
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
8
7
FGS
REAcq
7
6
OBAD
with Maneuver 6 6
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
ACS/WFC
11996
CCD
Daily Monitor (Part 3)
This
program comprises basic tests for measuring the read noise and dark
current
of the ACS WFC and for tracking the growth of hot pixels. The
recorded
frames are used to create bias and dark reference images for
science
data reduction and calibration. This program will be executed
four
days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To
facilitate
scheduling, this program is split into three proposals. This
proposal
covers 308 orbits (19.25 weeks) from 21 June 2010 to 1 November
2010.
ACS/WFC
12210
SLACS
for the Masses: Extending Strong Lensing to Lower Masses and
Smaller
Radii
Strong
gravitational lensing provides the most accurate possible
measurement
of mass in the central regions of early-type galaxies
(ETGs).
We propose to continue the highly productive Sloan Lens ACS
(SLACS)
Survey for strong gravitational lens galaxies by observing a
substantial
fraction of 135 new ETG gravitational-lens candidates with
HST-ACS
WFC F814W Snapshot imaging. The proposed target sample has been
selected
from the seventh and final data release of the Sloan Digital
Sky
Survey, and is designed to complement the distribution of previously
confirmed
SLACS lenses in lens-galaxy mass and in the ratio of Einstein
radius
to optical half-light radius. The observations we propose will
lead
to a combined SLACS sample covering nearly two decades in mass,
with
dense mapping of enclosed mass as a function of radius out to the
half-light
radius and beyond. With this longer mass baseline, we will
extend
our lensing and dynamical analysis of the mass structure and
scaling
relations of ETGs to galaxies of significantly lower mass, and
directly
test for a transition in structural and dark-matter content
trends
at intermediate galaxy mass. The broader mass coverage will also
enable
us to make a direct connection to the structure of well-studied
nearby
ETGs as deduced from dynamical modeling of their line-of-sight
velocity
distribution fields. Finally, the combined sample will allow a
more
conclusive test of the current SLACS result that the intrinsic
scatter
in ETG mass-density structure is not significantly correlated
with
any other galaxy observables. The final SLACS sample at the
conclusion
of this program will comprise approximately 130 lenses with
known
foreground and background redshifts, and is likely to be the
largest
confirmed sample of strong-lens galaxies for many years to come.
COS/NUV/FUV
11535
COS-GTO:
Deep Search for an Oxygen Atmosphere on Callisto
We
plan a deep search for 1304? and 1356? O emission from Callisto, to
detect
or place strong limits on the presence of a hypothesized O2
atmosphere
on this moon (Liang et al. 2005). Tenuous oxygen atmospheres
on
Europa and Ganymede have been detected by HST using these emission
lines,
but searches for O emission from Callisto have not been
successful
(Strobel et al. 2002). The Liang et al. models predict O
emission
at levels comparable to the Strobel et al. upper limit, so the
improved
sensitivity of COS may be able to detect the emission, and thus
Callisto's
O2 atmosphere, for the first time.
WFC3/UV
11638
Illuminating
the HI Structure of a Proto-cluster Region at z=2.84
We
propose very deep intermediate-band Lyman alpha imaging in the field
of
a newly-discovered proto-cluster region surrounding the extremely
luminous
QSO HS1549+19 at z=2.844. The large structure, initially
discovered
in a spectroscopic survey of galaxies in fields surrounding
the
brightest QSOs at z=2.5-2.8, represents an ideal laboratory for
studying
the response of the intergalactic medium to a source of
ionizing
photons that exceeds the UV background by factors >1000. Within
a
single pointing of WFC3-UVIS there are already more than 45 known
Lyman
alpha emitters, most of which are already spectroscopically
confirmed,
and at least 3 of which are giant "Lyman alpha blobs''. Many
of
the objects have properties similar to those expected from the
process
of fluorescence, in which Lyman alpha emission is induced by the
UV
radiation field of the QSO in any HI gas that dense enough to remain
partially
self-shielded. Fortuitously, the F467M filter (Stromgren "b")
in
WFC3-UVIS is a perfect match to Lyman alpha at z=2.844. In
combination
with an equally deep broad-band continuum image, the
observations
will allow the construction of a Lyman alpha map tracing
dense
gas throughout the inner parts of a proto-cluster region at
sub-kpc
resolution. The ability to measure the spatial sub-structure and
surface
brightness distribution of Lya emission, relative to known
protocluster
galaxies and AGN, will illuminate the "cosmic web'' in a
dense
region caught in a violent stage of formation.
STIS/CCD/MA
11668
Cosmo-chronometry
and Elemental Abundance Distribution of the Ancient
Star
HE1523-0901
We
propose to obtain near-UV HST/STIS spectroscopy of the extremely
metal-poor,
highly r-process-enhanced halo star HE 1523-0901, in order
to
produce the most complete abundance distribution of the heaviest
stable
elements, including platinum, osmium, and lead. These HST
abundance
data will then be used to estimate the initial abundances of
the
long-lived radioactive elements thorium and uranium, and by
comparison
with their observed abundances, enable an accurate age
determination
of this ancient star. The use of radioactive chronometers
in
stars provides an independent lower limit on the age of the Galaxy,
which
can be compared with alternative limits set by globular clusters
and
by analysis from WMAP. Our proposed observations of HE1523-0901 will
also
provide significant new information about the early chemical
history
of the Galaxy, specifically, the nature of the first generations
of
stars and the types of nucleosynthetic processes that occurred at the
onset
of Galactic chemical evolution.
STIS/CCD
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
STIS/CCD
11847
CCD
Bias Monitor-Part 2
Monitor
the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and
1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution
of hot columns.
COS/FUV
11895
FUV
Detector Dark Monitor
Monitor
the FUV detector dark rate by taking long science exposures
without
illuminating the detector. The detector dark rate and spatial
distribution
of counts will be compared to pre-launch and SMOV data in
order
to verify the nominal operation of the detector. Variations of
count
rate as a function of orbital position will be analyzed to find
dependence
of dark rate on proximity to the SAA. Dependence of dark rate
as
function of time will also be tracked.
WFC3/IR
11738
SPIDERWEBS
AND FLIES: OBSERVING MASSIVE GALAXY FORMATION IN ACTION
Distant
luminous radio galaxies are among the brightest known galaxies
in
the early Universe, pinpoint likely progenitors of dominant cluster
galaxies
and are unique laboratories for studying massive galaxy
formation.
Spectacular images with the ACS and NICMOS of one such
object,
the "Spiderweb Galaxy" at z = 2.2, show in exquisite detail,
hierarchical
merging occurring 11 Gyr ago. By imaging 3 additional
Spiderweb-like
galaxies we wish to study this potentially crucial phase
of
massive galaxy evolution, when hierarchical merging, galaxy
downsizing
and AGN feedback are all likely to be occurring. Properties
of
the complete sample of Spiderweb galaxies will be used to (i)
constrain
models for the formation and evolution of the most massive
galaxies
that dominate rich clusters and (ii) investigate the nature of
chain
and tadpole galaxies, a fundamental but poorly understood
constituent
of the early Universe.
We
shall image rest-frame UV and optical continuum emission from 3 radio
galaxies
with 2.4 < z < 3.8 that appear clumpy and large in shallow
WFPC/PC
observations. The new observations will typically reach ~2
magnitudes
fainter over 20-40 times larger area than previously.
Photometric
and morphological parameters will be measured for satellite
galaxies
("flies") in the clumpy massive hosts and for galaxies in ~ 1.5
Mpc
x 1.5 Mpc regions of surrounding protoclusters. Locations, sizes,
elongations,
clumpiness, masses, and star formation rates of the merging
satellite
and protocluster galaxies will be compared with new state of
the
art simulations. Combination of ACS and WFC3 images will help
disentangle
the properties of the young and old populations.
Specific
goals include: (i) investigating star formation histories of
the
satellite galaxies and the extended emission,
(ii)
studying "downsizing" and merging scenarios and (iii) measuring the
statistics
of linear galaxies and relating them to models for the
formation
of massive galaxies and to the properties of the important but
enigmatic
class of chain/tadpole galaxies in the HUDF.
WFC3/IR
12181
The
Atmospheric Structure of Giant Hot Exoplanets
Characterization
of close-in giant exoplanets has proceeded rapidly over
the
past few years, due largely to Spitzer and HST observations in
transiting
systems. Low resolution thermal emission spectra of over two
dozen
planets have been measured by Spitzer, and HST observations of a
few
key planets have indicated unusual molecular abundances via
transmission
spectroscopy. However, current models for the atmospheric
structure
of these worlds exhibit degeneracies wherein different
combinations
of temperature and molecular abundance profiles can fit the
same
Spitzer data for each planet. Fortunately, the advent of the IR
capability
on HST/WFC3 allows us to solve this major problem in
exoplanet
science. We propose to inaugurate a Large HST program that is
scientifically
complementary to Spitzer, Kepler, and CoRoT exoplanet
results.
We
will obtain transmission spectroscopy of the 1.4-micron water band in
a
sample of 13 planets, using the G141 grism on WFC3. Among the abundant
molecules,
only water absorbs at this wavelength, and our measurement of
water
abundance will enable us to break the degeneracies in the Spitzer
results
with minimal model assumptions. We will also use the G141 grism
to
observe secondary eclipses for 7 very hot giant exoplanets at
1.5-microns,
including several bright systems in the Kepler and CoRoT
fields.
The strong temperature sensitivity of the thermal continuum at
1.5-microns
provides high leverage on atmospheric temperature for these
worlds,
again helping to break degeneracies in interpreting the Spitzer
data.
Moreover, our precise eclipse photometry, in combination with
extant
Spitzer data, will enable us to extrapolate the thermal continuum
to
optical wavelengths. Kepler and CoRoT teams will be thereby able to
subtract
the thermal contribution from their increasingly precise
measurements
of optical eclipses, and measure, or place extremely
stringent
limits on, the albedo of these exotic worlds.
WFC3/UV/IR
12234
Differentiation
in the Kuiper belt: a Search for Silicates on Icy
Bodies.
We
currently have a large on-going program (Go Program 11644, 120
orbits)
to exploit the superb stability and photometric characteristics
of
HST and the broad range in wavelength coverage of the WFC3 to make
broad-band
vis/IR spectral observations of a large sample of Kuiper belt
objects.
Though the survey is currently only ~50% complete, the quality
and
unprecedented signal-to-noise of these observations has revealed the
existence
of a previously undiscovered spectral variability not
explainable
within our current understanding of these objects.
A
possible explanation for this variability is that with this faint set
of
Kuiper belt objects, we are beginning to see the difference between
larger
differentiated objects and smaller non-differentiated objects.
Its
seems that the small and likely undifferentiated objects are
exhibiting
silicate features that affect our photometry - features not
exhibited
by the icy mantles of larger icy bodies.
We
propose a small add-on survey to dramatically increase the scientific
results
of our large program. The proposed observations will use the
proven
capabilities of WFC3 to make broad and narrow-band photometric
observations
to detect spectral features in the 1.0-1.3 micron range of
a
small subset of our sources. The 13 targets have been carefully
selected
to cover the range of spectral variability detected in our
large
program as well as sample the entire dynamical range and physical
sizes
of these targets. These observations will allow the identification
of
undifferentiated Kuiper belt objects by detection of their silicate
features.
As a probe for differentiation, these observations could
constrain
the natal locations of different Kuiper belt classes, a
constraint
currently unavailable to formation models. This small set of
observations
will allow the calibration of the spectral variability seen
in
our large program, and drastically enhance the scientific output of
our
full Cycle 17 sample.
ACS/WFC
12292
SWELLS:
Doubling the Number of Disk-dominated Edge-on Spiral Lens
Galaxies
The
formation of realistic disk galaxies within the LCDM cosmology is
still
largely an unsolved problem. Theory is now beginning to make
predictions
for how dark matter halos respond to galaxy formation, and
for
the properties of disk galaxies. Measuring the density profiles of
dark
matter halos on galaxy scales is therefore a strong test for the
standard
paradigm of galaxy formation, offering great potential for
discovery.
However, the degeneracy between the stellar and dark matter
contributions
to galaxy rotation curves remains a major obstacle. Strong
gravitational
lensing, when combined with spatially resolved kinematics
and
stellar population models, can solve this long-standing problem.
Unfortunately,
this joint methodology could not be exploited until
recently
due to the paucity of known edge-on spiral lenses. We have
developed
and demonstrated an efficient technique to find exactly these
systems.
During supplemental cycle-16 we discovered five new spiral lens
galaxies,
suitable for rotation curve measurements. We propose
multi-color
HST imaging of 16 candidates and 2 partially-imaged
confirmed
systems, to measure a sample of eight new edge-on spiral
lenses.
This program will at least double the number of known
disk-dominated
systems. This is crucial for constraining the relative
contribution
of the disk, bulge and dark halo to the total density
profile.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
WFC3/UVIS
11912
UVIS
Internal Flats
This
proposal will be used to assess the stability of the flat field
structure
for the UVIS detector throughout the 15 months of Cycle 17.
The
data will be used to generate on-orbit updates for the delta-flat
field
reference files used in the WFC3 calibration pipeline, if
significant
changes in the flat structure are seen.
WFC3/UVIS
11914
UVIS
Earth Flats
This
program is an experimental path finder for Cycle 18 calibration.
Visible-wavelength
flat fields will be obtained by observing the dark
side
of the Earth during periods of full moon illumination. The
observations
will consist of full-frame streaked WFC3 UVIS imagery: per
22-
min total exposure time in a single "dark-sky" orbit, we anticipate
collecting
7000 e/pix in F606W or 4500 e/pix in F814W. To achieve
Poisson
S/N > 100 per pixel, we require at least 2 orbits of F606W and 3
orbits
of F814W.
For
UVIS narrowband filters, exposures of 1 sec typically do not
saturate
on the sunlit Earth, so we will take sunlit Earth flats for
three
of the more-commonly used narrowband filters in Cycle 17 plus the
also-popular
long-wavelength quad filters, for which we get four filters
at
once.
Why
not use the Sunlit Earth for the wideband visible-light filters? It
is
too bright in the visible for WFC3 UVIS minimum exposure time of 0.5
sec.
Similarly, for NICMOS the sunlit-Earth is too bright which
saturates
the detector too quickly and/or induces abnormal behaviors
such
as super-shading (Gilmore 1998, NIC 098-011). In the narrowband
visible
and broadband near- UV is not too bright (predictions in Cox et
al.
1987 "Standard Astronomical Sources for HST: 6. Spatially Flat
Fields."
and observations in ACS Program 10050).
Other
possibilities? Cox et al.'s Section II.D addresses many other
possible
sources for flat fields, rejecting them for a variety of
reasons.
A remaining possibility would be the totally eclipsed moon.
Such
eclipses provide approximately 2 hours (1 HST orbit) of opportunity
per
year, so they are too rare to be generically useful. An advantage of
the
moon over the Earth is that the moon subtends less than 0.25 square
degree,
whereas the Earth subtends a steradian or more, so scattered
light
and light potentially leaking around the shutter presents
additional
problems for the Earth. Also, we're unsure if HST can point
180
deg from the Sun.