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Daily Report #5177



 
 
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Old September 9th 10, 04:23 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report #5177

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.

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