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Daily Report #5185



 
 
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Old September 21st 10, 03:57 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5185

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5185

PERIOD COVERED: 5am September 20 - 5am September 21, 2010 (DOY 263/09:00z-264/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12420 - GSAcq(1,2,1) at 263/23:12:48z and REAcq(1,2,1) scheduled at
264/00:25:23z, at 264/02:01:18z, at 264/03:37:13z, and at
264/05:13:08z all failed to RGA Hold (gyro control) with Search Radius
Limit Exceeded on FGS-1

Observations affected: COS 30-35 Proposal ID#11598; WFC3 18-19
Proposal ID#11905; STIS 9-10 Proposal ID#11845; WFC3 20-22 & 24-32
Proposal ID#11696; WFC3 23 Proposal ID#11929; STIS 11-13 Proposal
ID#11847 .

HSTAR FOR DOY 253-254:

12418 - GSAcq(2,1,1) at 254/05:10:52z required multiple attempts to
achieve CT-DV on FGS2
12419 - GSAcq(1,2,1) at 253/19:08:29Z required two attempts to achieve
CT-DV on FGS1.


COMPLETED OPS REQUEST:

18568-1 - LBBIAS Updates for Extended Gyro Guiding Intervals
18922-2 - R/T OBAD to Correct Attitude Error
18923-0 - R/T OBAD to Correct Attitude Error Before Next GSacq

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 9 8
FGS REAcq 8 4
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 12166

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful HST/ACS SNAPshot
survey of a sample of 123 very X-ray luminous clusters in the redshift
range 0.3-0.7, detected and compiled by the MACS cluster survey. As
demonstrated by dedicated HST observations of the 12 most distant MACS
clusters (GO-09722) as well as by the MACS SNAPshots of an additional
25 obtained with ACS so far in Cycles 14 and 15, these systems
frequently exhibit strong gravitational lensing as well as spectacular
examples of violent galaxy evolution. A large number of additional
MACS SNAPs have since been obtained with WFPC2, leading to the
discovery of several more powerful cluster lenses. The dramatic loss,
however, of depth, field-of-view, and angular resolution compared to
ACS led to significantly reduced scientific returns, underlining the
need for ACS for this project. The proposed observations will provide
important constraints on the cluster mass distributions, on the
physical nature of ! galaxy-galaxy and galaxy-gas interactions in
cluster cores, and will yield a set of optically bright, lensed
galaxies for further 8-10m spectroscopy. For those of our targets with
existing ACS SNAPshot images, we propose SNAPshots in the WFC3 F110W
and F140W passbands to obtain colour information that will greatly
improve the secure identification of multiple-image systems and may,
in the form of F606W or F814W dropouts, lead to the lensing-enabled
discovery of very distant galaxies at z5. Acknowledging the broad
community interest in this sample (16 of the 25 targets of the
approved MCT cluster program are MACS discoveries) we waive our data
rights for these observations.

This proposal is an updated and improved version of our successful
Cycle 15 proposal of the same title. Alas, SNAP-10875 collected only
six snapshots in the F606W or F814W passbands, due to, first, a
clerical error at STScI which caused the program to be barred from
execution for four months and, ultimately, the failure of ACS. With
ACS restored, and WFC3 providing additional wavelength and redshift
leverage, we wish to resume this previously approved project.

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.

ACS/WFC3 11575

The Stellar Origins of Supernovae

Supernovae (SNe) have a profound effect on galaxies, and have been
used recently as precise cosmological probes, resulting in the
discovery of the accelerating Universe. They are clearly very
important events deserving of intense study. Yet, even with nearly
4000 known SNe, we know relatively little about the stars which give
rise to these powerful explosions. The main limitation has been the
lack of spatial resolution in pre-SN imaging data. However, since 1999
our team has been at the vanguard of directly identifying SN
progenitor stars in HST images. From this exciting new line of study,
the emerging trend from 5 detections for Type II- Plateau SNe is that
their progenitors appear to be relatively low mass (8 to 20 Msun) red
supergiants, although more cases are needed. Nonetheless, the nature
of the progenitors of Type Ib/c SNe, a subset of which are associated
with the amazing gamma-ray bursts, remains ambiguous. Furthermore, we
remain in the continually embarrassing situation that we still do not
yet know which progenitor systems explode as Type Ia SNe, which are
currently being used for precision cosmology. In Cycle 16 we have
triggered on the Type Ic SN 2007gr and Type IIb SN 2008ax so far. We
propose to determine the identities of the progenitors of 4 SNe within
17 Mpc, which we expect to occur during Cycle 17, through ToO
observations using ACS/HRC.

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.

COS/FUV 11897

FUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity in each FUV
grating mode to detect any changes due to contamination or other
causes.

COS/FUV 11997

FUV Internal/External Wavelength Scale Monitor

This program monitors the offsets between the wavelength scale set by
the internal wavecal versus that defined by absorption lines in
external targets. This is accomplished by observing two external
targets in the SMC: SK191 with G130M and G160M and Cl* NGC 330 ROB B37
with G140L (SK191 is too bright to be observed with G140L). The
cenwaves observed in this program are a subset of the ones used during
Cycle 17. Observing all cenwaves would require a considerably larger
number of orbits. Constraints on scheduling of each target are placed
so that each target is observed once every ~2-3 months. Observing the
two targets every month would also require a considerably larger
number of orbits.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate
by taking long science exposures with no light on 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.

COS/NUV/FUV 11598

How Galaxies Acquire their Gas: A Map of Multiphase Accretion and
Feedback in Gaseous Galaxy Halos

We propose to address two of the biggest open questions in galaxy
formation - how galaxies acquire their gas and how they return it to
the IGM - with a concentrated COS survey of diffuse multiphase gas in
the halos of SDSS galaxies at z = 0.15 - 0.35. Our chief science goal
is to establish a basic set of observational facts about the physical
state, metallicity, and kinematics of halo gas, including the sky
covering fraction of hot and cold material, the metallicity of infall
and outflow, and correlations with galaxy stellar mass, type, and
color - all as a function of impact parameter from 10 - 150 kpc.
Theory suggests that the bimodality of galaxy colors, the shape of the
luminosity function, and the mass-metallicity relation are all
influenced at a fundamental level by accretion and feedback, yet these
gas processes are poorly understood and cannot be predicted robustly
from first principles. We lack even a basic observational assessment
of the multiphase gaseous content of galaxy halos on 100 kpc scales,
and we do not know how these processes vary with galaxy properties.
This ignorance is presently one of the key impediments to
understanding galaxy formation in general. We propose to use the
high-resolution gratings G130M and G160M on the Cosmic Origins
Spectrograph to obtain sensitive column density measurements of a
comprehensive suite of multiphase ions in the spectra of 43 z 1 QSOs
lying behind 43 galaxies selected from the Sloan Digital Sky Survey.
In aggregate, these sightlines will constitute a statistically sound
map of the physical state and metallicity of gaseous halos, and
subsets of the data with cuts on galaxy mass, color, and SFR will seek
out predicted variations of gas properties with galaxy properties. Our
interpretation of these data will be aided by state-of-the-art
hydrodynamic simulations of accretion and feedback, in turn providing
information to refine and test such models. We will also use Keck,
MMT, and Magellan (as needed) to obtain optical spectra of the QSOs to
measure cold gas with Mg II, and optical spectra of the galaxies to
measure SFRs and to look for outflows. In addition to our other
science goals, these observations will help place the Milky Way's
population of multiphase, accreting High Velocity Clouds (HVCs) into a
global context by identifying analogous structures around other
galaxies. Our program is designed to make optimal use of the unique
capabilities of COS to address our science goals and also generate a
rich dataset of other absorption-line systems.

COS/NUV/FUV 11728

The Impact of Starbursts on the Gaseous Halos of Galaxies

Perhaps the most important (yet uncertain) aspects of galaxy evolution
are the processes by which galaxies accrete gas and by which the
resulting star formation and black hole growth affects this accreting
gas. It is believed that both the form of the accretion and the nature
of the feedback change as a function of the galaxy mass. At low mass
the gas comes in cold and the feedback is provided by massive stars.
At high mass, the gas comes in hot, and the feedback is from an AGN.
The changeover occurs near the mass where the galaxy population
transitions from star-forming galaxies to red and dead ones. The
population of red and dead galaxies is building with cosmic time, and
it is believed that feedback plays an important role in this process:
shutting down star formation by heating and/or expelling the reservoir
of cold halo gas. To investigate these ideas, we propose to use COS
far-UV spectra of background QSOs to measure the properties of the
halo gas in a sample of galaxies near the transition mass that have
undergone starbursts within the past 100 Myr to 1 Gyr. The galactic
wind associated with the starburst is predicted to have affected the
properties of the gaseous halo. To test this, we will compare the
properties of the halos of the post-starburst galaxies to those of a
control sample of galaxies matched in mass and QSO impact parameter.
Do the halos of the post-starburst galaxies show a higher incidence
rate of Ly-Alpha and metal absorption-lines? Are the kinematics of the
halo gas more disturbed in the post-starbursts? Has the wind affected
the ionization state and/or the metallicity of the halo? These data
will provide fresh new insights into the role of feedback from massive
stars on the evolution of galaxies, and may also offer clues about the
properties of the QSO metal absorption-line systems at high-redshift .

NIC2/WFC3/IR 11548

Infrared Imaging of Protostars in the Orion A Cloud: The Role of
Environment in Star Formation

We propose NICMOS and WFC3/IR observations of a sample of 252
protostars identified in the Orion A cloud with the Spitzer Space
Telescope. These observations will image the scattered light escaping
the protostellar envelopes, providing information on the shapes of
outflow cavities, the inclinations of the protostars, and the overall
morphologies of the envelopes. In addition, we ask for Spitzer time to
obtain 55-95 micron spectra of 75 of the protostars. Combining these
new data with existing 3.6 to 70 micron photometry and forthcoming
5-40 micron spectra measured with the Spitzer Space Telescope, we will
determine the physical properties of the protostars such as envelope
density, luminosity, infall rate, and outflow cavity opening angle. By
examining how these properties vary with stellar density (i.e.
clusters vs. groups vs. isolation) and the properties of the
surrounding molecular cloud; we can directly measure how the
surrounding environment influences protostellar evolution, and
consequently, the formation of stars and planetary systems.
Ultimately, this data will guide the development of a theory of
protostellar evolution.

STIS/CCD 11721

Verifying the Utility of Type Ia Supernovae as Cosmological Probes:
Evolution and Dispersion in the Ultraviolet Spectra

The study of distant type Ia supernova (SNe Ia) offers the most
practical and immediate discriminator between popular models of dark
energy. Yet fundamental questions remain over possible
redshift-dependent trends in their observed and intrinsic properties.
High-quality Keck spectroscopy of a representative sample of 36
intermediate redshift SNe Ia has revealed a surprising, and
unexplained, diversity in their rest-frame UV fluxes. One possible
explanation is hitherto undiscovered variations in the progenitor
metallicity. Unfortunately, this result cannot be compared to local UV
data as only two representative SNe Ia have been studied near maximum
light. Taking advantage of two new `rolling searches' and the
restoration of STIS, we propose a non-disruptive TOO campaign to
create an equivalent comparison local sample. This will allow us to
address possible evolution in the mean UV spectrum and its diversity,
an essential precursor to the study of SNe beyond z~1.

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.

STIS/CCD 11852

STIS CCD Spectroscopic Flats C17

The purpose of this proposal is to obtain pixel-to-pixel lamp flat
fields for the STIS CCD in spectroscopic mode.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by Gos in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

WFC3/UV 12215

Searching for the Missing Low-Mass Companions of Massive Stars

Recent results on binary companions of massive O stars appear to
indicate that the distribution of secondary masses is truncated at low
masses. It thus mimics the distribution of companions of G dwarfs and
also the Initial Mass Function (IMF), except that it is shifted upward
by a factor of 20 in mass. These results, if correct, provide a
distribution of mass ratios that hints at a strong constraint on the
star-formation process. However, this intriguing result is derived
from a complex simulation of data which suffer from observational
incompleteness at the low-mass end.

We propose a snapshot survey to test this result in a very direct way.
HST WFC3 images of a sample of the nearest Cepheids (which were
formerly B stars of ~5 Msun) will search for low-mass companions down
to M dwarfs. We will confirm any companions as young stars, and thus
true physical companions, through follow-up Chandra X-ray images. Our
survey will show clearly whether the companion mass distribution is
truncated at low masses, but at a mass much higher than that of the
IMF or G dwarfs.

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.

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/IR 11696

Infrared Survey of Star Formation Across Cosmic Time

We propose to use the unique power of WFC3 slitless spectroscopy to
measure the evolution of cosmic star formation from the end of the
reionization epoch at z6 to the close of the galaxy-building era at
z~0.3.Pure parallel observations with the grisms have proven to be
efficient for identifying line emission from galaxies across a broad
range of redshifts. The G102 grism on WFC3 was designed to extend this
capability to search for Ly-alpha emission from the first galaxies.
Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will
observe about 40 deep (4-5 orbit) fields with the combination of G102
and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.

Our primary science goals at the highest redshifts a (1) Detect Lya
in ~100 galaxies with z5.6 and measure the evolution of the Lya
luminosity function, independent of of cosmic variance; 2) Determine
the connection between emission line selected and continuum-break
selected galaxies at these high redshifts, and 3) Search for the
proposed signature of neutral hydrogen absorption at re-ionization. At
intermediate redshifts we will (4) Detect more than 1000 galaxies in
Halpha at 0.5z1.8 to measure the evolution of the
extinction-corrected star formation density across the peak epoch of
star formation. This is over an order-of-magnitude improvement in the
current statistics, from the NICMOS Parallel grism survey. (5) Trace
``cosmic downsizing" from 0.5z2.2; and (6) Estimate the evolution in
reddening and metallicty in star-forming galaxies and measure the
evolution of the Seyfert population. For hundreds of spectra we will
be able to measure one or even two line pair ratios -- in particular,
the Balmer decrement and [OII]/[OIII] are sensitive to gas reddening
and metallicity. As a bonus, the G102 grism offers the possibility of
detecting Lya emission at z=7-8.8.

To identify single-line Lya emitters, we will exploit the wide
0.8--1.9um wavelength coverage of the combined G102+G141 spectra. All
[OII] and [OIII] interlopers detected in G102 will be reliably
separated from true LAEs by the detection of at least one strong line
in the G141 spectrum, without the need for any ancillary data. We
waive all proprietary rights to our data and will make high-level data
products available through the ST/ECF.

WFC3/UVIS/IR 11700

Bright Galaxies at z7.5 with a WFC3 Pure Parallel Survey

The epoch of reionization represents a special moment in the history
of the Universe as it is during this era that the first galaxies and
star clusters are formed. Reionization also profoundly affects the
environment where subsequent generations of galaxies evolve. Our
overarching goal is to test the hypothesis that galaxies are
responsible for reionizing neutral hydrogen. To do so we propose to
carry out a pure parallel WFC3 survey to constrain the bright end of
the redshift z7.5 galaxy luminosity function on a total area of 176
arcmin^2 of sky. Extrapolating the evolution of the luminosity
function from z~6, we expect to detect about 20 Lyman Break Galaxies
brighter than M_* at z~8 significantly improving the current sample of
only a few galaxies known at these redshifts. Finding significantly
fewer objects than predicted on the basis of extrapolation from z=6
would set strong limits to the brightness of M_*, highlighting a fast
evolution of the luminosity function with the possible implication
that galaxies alone cannot reionize the Universe. Our observations
will find the best candidates for spectroscopic confirmation, that is
bright z7.5 objects, which would be missed by small area deeper
surveys. The random pointing nature of the program is ideal to beat
cosmic variance, especially severe for luminous massive galaxies,
which are strongly clustered. In fact our survey geometry of 38
independent fields will constrain the luminosity function like a
contiguous single field survey with two times more area at the same
depth. Lyman Break Galaxies at z7.5 down to m_AB=26.85 (5 sigma) in
F125W will be selected as F098M dropouts, using three to five orbits
visits that include a total of four filters (F606W, F098M, F125W,
F160W) optimized to remove low-redshift interlopers and cool stars.
Our data will be highly complementary to a deep field search for
high-z galaxies aimed at probing the faint end of the luminosity
function, allowing us to disentangle the degeneracy between faint end
slope and M_* in a Schechter function fit of the luminosity function.
We waive proprietary rights for the data. In addition, we commit to
release the coordinates and properties of our z7.5 candidates within
one month from the acquisition of each field.


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