HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science
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DAILY REPORT #5101
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PERIOD COVERED: 5am May 20 - 5am May 21, 2010 (DOY 140/09:00z-141/09:00z)
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FLIGHT OPERATIONS SUMMARY:
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Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
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HSTARS:
12285 - OBD Failed Quaternion @ 140/15:38:34z. GSAcq(1,0,1) at 140/15:52:06z
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COMPLETED OPS REQUEST:
17543-3 - Dump OBAD tables after failed OBAD
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COMPLETED OPS NOTES: (None)
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OBAD with Maneuver 6 ��� ��������5�
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SIGNIFICANT EVENTS: (None)
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OBSERVATIONS SCHEDULED:
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ACS/WFC 11591
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Are Low-Luminosity Galaxies Responsible for Cosmic Reionization?
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Our group has demonstrated that massive clusters, acting as powerful
cosmic lenses, can constrain the abundance and properties of
low-luminosity star-forming sources beyond z~6; such sources are thought
to be responsible for ending cosmic reionization. The large
magnification possible in the critical regions of well-constrained
clusters brings sources into view that lie at or beyond the limits of
conventional exposures such as the UDF. We have shown that the
combination of HST and Spitzer is particularly effective in delivering
the physical properties of these distant sources, constraining their
mass, age and past star formation history. Indirectly, we therefore gain
a valuable glimpse to yet earlier epochs. Recognizing the result (and
limitations) of blank field surveys, we propose a systematic search
through 10
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lensing clusters with ACS/F814W and WFC3/[F110W+F160W] (in conjunction
with existing deep IRAC data). Our goal is to measure with great
accuracy the luminosity function at z~7 over a range of at least 3
magnitude, based on the identification of about 50 lensed galaxies at
6.5<z<8. Our survey will mitigate cosmic variance and extend the search
both to lower luminosities and, by virtue of the WFC3/IRAC combination,
to higher redshift. Thanks to the lensing amplification spectroscopic
follow-up will be possible and make our findings the most robust prior
to the era of JWST and the ELTs.
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ACS/WFC 11995
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CCD Daily Monitor (Part 2)
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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 320 orbits (20 weeks) from 1 February 2010 to 20 June
2010.
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ACS/WFC/WFC3/IR 11597
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Spectroscopy of IR-Selected Galaxy Clusters at 1 < z < 1.5
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We propose to obtain WFC3 G141 and G102 slitless spectroscopy of galaxy
clusters at 1 < z < 1.5 that were selected from the IRAC survey of the
Bootes NDWFS field. Our IRAC survey contains the largest sample of
spectroscopically confirmed clusters at z > 1. The WFC3 grism data will
measure H-alpha to determine SFR, and fit models to the low resolution
continua to determine stellar population histories for the brighter
cluster members, and redshifts for the red galaxies too faint for
ground-based optical spectroscopy.
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ACS/WFC/WFC3/IR 11663
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Formation and Evolution of Massive Galaxies in the Richest Environments
at 1.5 < z < 2.0
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We propose to image seven 1.5<z<2 clusters and groups from the IRAC
Shallow Cluster Survey with WFC3 and ACS in order to study the formation
and evolution of massive galaxies in the richest environments in the
Universe in this important redshift range. We will measure the evolution
of the sizes and morphologies of massive cluster galaxies, as a function
of redshift, richness, radius and local density. In combination with
allocated Keck spectroscopy, we will directly measure the dry merger
fraction in these clusters, as well as the evolution of Brightest
Cluster Galaxies (BCGs) over this redshift range where clear model
predictions can be confronted. Finally we will measure both the epoch of
formation of the stellar populations and the assembly history of that
stellar mass, the two key parameters in the modern galaxy formation
paradigm.
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ACS/WFC/WFC3/IR/WFC3/UVI 11570
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Narrowing in on the Hubble Constant and Dark Energy
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A measurement of the Hubble constant to a precision of a few percent
would be a powerful aid to the investigation of the nature of dark
energy and a potent "end-to-end" test of the present cosmological model.
In Cycle 15 we constructed a new, streamlined distance ladder utilizing
high-quality type Ia supernova data and observations of Cepheids with
HST in the near-IR to minimize the dominant sources of systematic
uncertainty in past measurements of the Hubble constant and reduce its
total uncertainty to a little under 5%. Here we propose to exploit this
new route to reduce the remaining uncertainty by more than 30%,
translating into an equal reduction in the uncertainty of the equation
of state of dark energy. We propose three sets of observations to reach
this goal: a mosaic of NGC 4258 with WFC3 in F160W to triple its sample
of long period Cepheids, WFC3/F160W observations of the 6 ideal SN Ia
hosts to triple their samples of Cepheids, and observations of NGC 5584
the host of a new SN Ia, SN 2007af, to discover and measure its Cepheids
and begin expanding the small set of SN Ia luminosity calibrations.
These observations would provide the bulk of a coordinated program aimed
at making the measurement of the Hubble constant one of the leading
constraints on dark energy.
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COS/FUV/COS/NUV 11742
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Probing HeII Reionization with GALEX-selected Quasar Sightlines and
HST/COS
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We propose spectroscopic observations with COS of eight z~3 QSOs that we
found to be bright in the far ultraviolet. Our aim is to study
intergalactic absorption caused by the onset of the He II Lyman forest.
Several lines of evidence suggest that helium reionization occurred at
z~3. Understanding this process is critical for a complete picture of
the intergalactic medium and its evolution; it also gives clues to
hydrogen reionization at z>6. The only direct means of assessing He II
reionization is through far-UV observations of the He II Lyman alpha
forest. Only 6 sightlines are known to date where this is feasible,
despite extensive surveys. Our programme is designed to double the
number of available sightlines. To this effect, we cross-correlated all
known z>2.73 quasars with UV source lists from the GALEX satellite. The
selected quasars were all significantly detected in the far UV by GALEX,
and their UV colors are similar to those of already known quasars with
transparent sightlines. Spectra obtained with COS will allow us to
compile the first comprehensive sample of He II absorption spectra
probing similar redshifts, enabling a systematic investigation of the He
II reionization epoch and the spectral shape of the UV background.
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S/C/WFC3/IR 11929
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IR Dark Current Monitor
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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).
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STIS/CCD 11845
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CCD Dark Monitor Part 2
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Monitor the darks for the STIS CCD.
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STIS/CCD 11847
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CCD Bias Monitor-Part 2
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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.
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STIS/MA2 11857
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STIS Cycle 17 MAMA Dark Monitor
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This proposal monitors the behavior of the dark current in each of the
MAMA detectors.
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The basic monitor takes two 1380s ACCUM darks each week with each
detector. However, starting Oct 5, pairs are only included for weeks
that the LRP has external MAMA observations planned. The weekly pairs of
exposures for each detector are linked so that they are taken at
opposite ends of the same SAA free interval. This pairing of exposures
will make it easier to separate long and short term temporal variability
from temperature dependent changes.
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For both detectors, additional blocks of exposures are taken once every
six months. These are groups of five 1314 s FUV-MAMA TIME-TAG darks or
five 3x315 s NUV ACCUM darks distributed over a single SAA free
interval. This will give more information on the brightness of the FUV
MAMA dark current as a function of the amount of time that the HV has
been on, and for the NUV MAMA will give a better measure of the short
term temperature dependence.
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WFC3/IR 11696
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Infrared Survey of Star Formation Across Cosmic Time
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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 z>6 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.
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Our primary science goals at the highest redshifts are: (1) Detect Lya
in ~100 galaxies with z>5.6 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 0.5<z<1.8 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
0.5<z<2.2; 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 possiblity of detecting Lya emission at
z=7-8.8.
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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.
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WFC3/IR 11915
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IR Internal Flat Fields
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This program is the same as 11433 (SMOV) and depends on the completion
of the IR initial alignment (program 11425). This version contains three
instances of 37 internal orbits; to be scheduled early, middle, and near
the end of Cycle 17, in order to use the entire 110-orbit allocation.
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In this test, we will study the stability and structure of the IR
channel flat field images through all filter elements in the WFC3-IR
channel. Flats will be monitored, i.e. to capture any temporal trends in
the flat fields, and delta flats produced. High signal observations will
provide a map of the pixel-to-pixel flat field structure, as well as
identify the positions of any dust particles.
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WFC3/IR/WFC3/UVI 11557
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The Nature of low-ionization BAL QSOs
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The rare subclass of optically-selected QSOs known as low-ionization
broad absorption line (LoBAL) QSOs show signs of high-velocity gas
outflows and reddened continua indicative of dust obscuration. Recent
studies show that galaxies hosting LoBAL QSOs tend to be ultraluminous
infrared systems that are undergoing mergers, and that have dominant
young (< 100 Myr) stellar populations. Such studies support the idea
that LoBAL QSOs represent a short-lived phase early in the life of QSOs,
when powerful AGN-driven winds are blowing away the dust and gas
surrounding the QSO. If so, understanding LoBALs would be critical in
the study of phenomena regulating black hole and galaxy evolution, such
as AGN feedback and the early stages of nuclear accretion. These
results, however, come from very small samples that may have serious
selection biases. We are therefore taking a more aggressive approach by
conducting a systematic multiwavelength study of a volume limited sample
of LoBAL QSOs at 0.5 < z < 0.6 drawn from SDSS. We propose to image
their host galaxies in two bands using WFC3/UVIS and WFC3/IR to study
the morphologies for signs of recent tidal interactions and to map their
interaction and star forming histories. We will thus determine whether
LoBAL QSOs are truly exclusively found in young merging systems that are
likely to be in the early stages of nuclear accretion.
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WFC3/UVI 11360
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Star Formation in Nearby Galaxies
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Star formation is a fundamental astrophysical process; it controls
phenomena ranging from the evolution of galaxies and nucleosynthesis to
the origins of planetary systems and abodes for life. The WFC3,
optimized at both UV and IR wavelengths and equipped with an extensive
array of narrow-band filters, brings unique capabilities to this area of
study. The WFC3 Scientific Oversight Committee (SOC) proposes an
integrated program on star formation in the nearby universe which will
fully exploit these new abilities. Our targets range from the
well-resolved R136 in 30 Dor in the LMC (the nearest super star cluster)
and M82 (the nearest starbursting galaxy) to about half a dozen other
nearby galaxies that sample a wide range of star-formation rates and
environments. Our program consists of broad-band multiwavelength imaging
over the entire range from the UV to the near-IR, aimed at studying the
ages and metallicities of stellar populations, revealing young stars
that are still hidden by dust at optical wavelengths, and showing the
integrated properties of star clusters. Narrow-band imaging of the same
environments will allow us to measure star-formation rates, gas
pressure, chemical abundances, extinction, and shock morphologies. The
primary scientific issues to be addressed are: (1) What triggers star
formation? (2) How do the properties of star-forming regions vary among
different types of galaxies and environments of different gas densities
and compositions? (3) How do these different environments affect the
history of star formation? (4) Is the stellar initial mass function
universal or determined by local conditions?
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WFC3/UVI 11905
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WFC3 UVIS CCD Daily Monitor
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The behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame, four-amp bias<BR>and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals<BR>throughout
the cycle to support subarray science observations. The internals from
this proposal,<BR>along with those from the anneal procedure (11909),
will be used to generate the necessary superbias<BR>and superdark
reference files for the calibration pipeline (CDBS).
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WFC3/UVI 11908
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Cycle 17: UVIS Bowtie Monitor
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Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab tests
have further revealed that overexposing the detector to count levels
several times full well fills the traps and effectively neutralizes the
bowtie. Each visit in this proposal acquires a set of three 3x3 binned
internal flatfields: the first unsaturated image will be used to detect
any bowtie, the second, highly-exposed image will neutralize the bowtie
if it is present, and the final image will allow for verification that
the bowtie is gone.