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Daily Report #5139

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Old July 16th 10, 05:03 PM posted to sci.astro.hubble
Bassford, Lynn
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Posts: 44
Default Daily Report #5139

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science


PERIOD COVERED: 5am July 15 - 5am July 16, 2010 (DOY 196/09:00z-197/09:00z)


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

HSTARS: (None)



FGS GSAcq 9 9
FGS REAcq 9 9
OBAD with Maneuver 5 5




Testing the Origin(s) of the Highly Ionized High-Velocity Clouds: A
Survey of Galactic Halo Stars at z3 kpc

Cosmological simulation predicts that highly ionized gas plays an
important role in the formation and evolution of galaxies and their
interplay with the intergalactic medium. The NASA HST and FUSE
missions have revealed high-velocity CIV and OVI absorption along
extragalactic sightlines through the Galactic halo. These highly
ionized high-velocity clouds (HVCs) could cover 85% of the sky and
have a detection rate higher than the HI HVCs. Two competing, equally
exciting, theories may explain the origin of these highly ionized
HVCs: 1) the "Galactic" theory, where the HVCs are the result of
feedback processes and trace the disk-halo mass exchange, perhaps
including the accretion of matter condensing from an extended corona;
2) the "Local Group" theory, where they are part of the local warm-hot
intergalactic medium, representing some of the missing baryonic matter
of the Universe. Only direct distance determinations can discriminate
between these models. Our group has found that some of these highly
ionized HVCs have a Galactic origin, based on STIS observations of one
star at z5.3 kpc. We propose an HST FUV spectral survey to search for
and characterize the high velocity NV, CIV, and SiIV interstellar
absorption toward 24 stars at much larger distances than any previous
searches (4d21 kpc, 3|z|13 kpc). COS will provide atomic to highly
ionized species (e.g.,OI, CII, CIV, SiIV) that can be observed at
sufficient resolution (R~22, 000) to not only detect these highly
ionized HVCs but also to model their properties and understand their
physics and origins. This survey is only possible because of the high
sensitivity of COS in the FUV spectral range.

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CC 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 11999

JWST Calibration from a Consistent Absolute Calibration of Spitzer &

Recently, Gordon, Bohlin, et al. submitted a successful Spitzer
proposal for cross calibration of HST and Spitzer. The
cross-calibration targets are stars in three categories: WDs, A-stars,
and G-stars. Traditionally, IR flux standards are extrapolations of
stellar models that are tied to absolute fluxes at shorter
wavelengths. HST absolute flux standards are among the best available
with a solid basis that uses pure hydrogen models of hot WD stars for
the SED slopes and is tied to Vega at 5556A via precise Landolt V-band
photometry. Consistently matching models to our three categories of
HST observations along with Spitzer photometry and the few existing
absolute IR flux determinations will provide a solid basis for JWST
flux calibration over its 0.8-30micron range. The goal of this
proposal is to complete the HST observations of the set of HST/Spitzer
cross-calibration stars. Using a variety of standard stars with three
different spectral types will ensure that the final calibration is not
significantly affected by systematic uncertainties.

WFC3/IR 11666

Chilly Pairs: A Search for the Latest-type Brown Dwarf Binaries and
the Prototype Y Dwarf

We propose to use HST/WFC3 to image a sample of 27 of the nearest (
20 pc) and lowest luminosity T-type brown dwarfs in order to identify
and characterize new very low mass binary systems. Only 3 late-type T
dwarf binaries have been found to date, despite that fact that these
systems are critical benchmarks for evolutionary and atmospheric
models at the lowest masses. They are also the most likely systems to
harbor Y dwarf companions, an as yet unpopulated putative class of
very cold (T 600 K) brown dwarfs. Our proposed program will more
than double the number of T5-T9 dwarfs imaged at high resolution, with
an anticipated yield of ~5 new binaries with initial characterization
of component spectral types. We will be able to probe separations
sufficient to identify systems suitable for astrometric orbit and
dynamical mass measurements. We also expect one of our discoveries to
contain the first Y-type brown dwarf. Our proposed program complements
and augments ongoing ground-based adaptive optics surveys and provides
pathway science for JWST.

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 11605

Obtaining the Missing Links in the Test of Very Low Mass Evolutionary
Models with HST

We are proposing for spatially resolved ACS+HRC observations of 11
very low mass binaries spanning late-M, L and T spectral types in
order to obtain precise effective temperature measurements for each
component. All of our targets are part of a program in which we are
measuring dynamical masses of very low-mass binaries to an
unprecedented precision of 10% (or better). However, without precise
temperature measurements, the full scientific value of these mass
measurements cannot be realized. Together, mass and temperature
measurements will allow us to distinguish between brown dwarf
evolutionary models that make different assumptions about the interior
and atmospheric structure of these ultra-cool objects. While dynamical
masses can be obtained from the ground in the near-IR, obtaining
precise temperatures require access to optical data which, for these
sub-arcsecond binaries, can only be obtained from space with Hubble.


A Panchromatic Hubble Andromeda Treasury - I

We propose to image the north east quadrant of M31 to deep limits in
the UV, optical, and near-IR. HST imaging should resolve the galaxy
into more than 100 million stars, all with common distances and
foreground extinctions. UV through NIR stellar photometry (F275W,
F336W with WFC3/UVIS, F475W and F814W with ACS/WFC, and F110W and
F160W with WFC3/NIR) will provide effective temperatures for a wide
range of spectral types, while simultaneously mapping M31's
extinction. Our central science drivers are to: understand high-mass
variations in the stellar IMF as a function of SFR intensity and
metallicity; capture the spatially-resolved star formation history of
M31; study a vast sample of stellar clusters with a range of ages and
metallicities. These are central to understanding stellar evolution
and clustered star formation; constraining ISM energetics; and
understanding the counterparts and environments of transient objects
(novae, SNe, variable stars, x-ray sources, etc.). As its legacy, this
survey adds M31 to the Milky Way and Magellanic Clouds as a
fundamental calibrator of stellar evolution and star-formation
processes for understanding the stellar populations of distant
galaxies. Effective exposure times are 977s in F275W, 1368s in F336W,
4040s in F475W, 4042s in F814W, 699s in F110W, and 1796s in F160W,
including short exposures to avoid saturation of bright sources. These
depths will produce photon-limited images in the UV. Images will be
crowding-limited in the optical and NIR, but will reach below the red
clump at all radii. The images will reach the Nyquist sampling limit
in F160W, F475W, and F814W.

WFC3/UVIS 11577

Opening New Windows on the Antennae with WFC3

We propose to use WFC3 to provide key observations of young star
clusters in "The Antennae" (NGC4038/39). Of prime importance is the
WFC3's ability to push the limiting UV magnitude FIVE mag deeper than
our previous WFPC2 observations. This corresponds to pushing the
limiting cluster mass from ~10**5 to ~10**3 solar masses for cluster
ages ~10**8 yrs. In addition, the much wider field of view of the WFC3
IR channel will allow us to map out both colliding disks rather than
just the Overlap Region between them. This will be especially
important for finding the youngest clusters that are still embedded in
their placental cocoons. The extensive set of narrow-band filters will
provide an effective means for determining the properties of shocks,
which are believed to be a primary triggering mechanism for star
formation. We will also use ACS in parallel with WFC3 to observe
portions of both the northern and southern tails at no additional
orbital cost. Finally, one additional primary WFC3 orbit will be used
to supplement exisiting HST observations of the star-forming "dwarf"
galaxy at the end of the southern tail. Hence, when completed we will
have full UBVI + H_alpha coverage (or more for the main galaxy) of
four different environments in the Antennae. In conjunction with the
extensive multi- wavelength database we have collected (both HST and
ground based) these observations will provide answers to fundamental
questions such as: How do these clusters form and evolve? How is star
formation triggered? How do star clusters affect the local and global
ISM, and the evolution of the galaxy as a whole? The Antennae galaxies
are the nearest example of a major disk--disk merger, and hence may
represent our best chance for understanding how mergers form
tremendous numbers of clusters and stars, both in the local universe
and during galaxy assembly at high redshift.

WFC3/UVIS 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.8 z 2.5, using WFC3 and the G280 grism. This
proposal intends to complete an approved Cycle 15 SNAP program
(10878), which was cut short due to the ACS failure. We have selected
64 quasars at 2.3 z 2.6 from the Sloan Digital Sky Survey
Spectroscopic Quasar Sample, for which no BAL signature is found at
the QSO redshift and no strong metal absorption lines are present at z
2.3 along the lines of sight. The survey has three main

observational goals. First, we will determine the redshift frequency
dn/dz of the LLS over the column density range 16.0 log(NHI) 20.3
cm^-2. Second, we will measure the column density frequency
distribution f(N) for the partial Lyman limit systems (PLLS) over the
column density range 16.0 log(NHI) 17.5 cm^-2. Third, we will
identify those sightlines which could provide a measurement of the
primordial D/H ratio. By carrying out this survey, we can also help
place meaningful constraints on two key quantities of cosmological
relevance. First, we will estimate the amount of metals in the LLS
using the f(N), and ground based observations of metal line
transitions. Second, by determining f(N) of the PLLS, we can constrain
the amplitude of the ionizing UV background at z~2 to a greater
precision. This survey is ideal for a snapshot observing program,
because the on-object integration times are all well below 30 minutes,
and follow-up observations from the ground require minimal telescope
time due to the QSO sample being bright.

WFC3/UVIS 11661

The Black Hole Mass - Bulge Luminosity Relationship for the Nearest
Reverberation-Mapped AGNs

We propose to obtain WFC3 host galaxy images of the eight nearest AGNs
with masses from reverberation mapping, and one star as a PSF model.
These images will allow us to determine with unprecedented accuracy
the bulge luminosities of the host galaxies, a goal which is not
achievable from the ground due to the blurring of the very bright PSF
component under typical, and even very good, seeing conditions.
High-resolution ACS images of the host galaxies of more luminous AGNs
reveal that the black hole mass-bulge luminosity and black hole
mass-bulge mass relationships for AGNs are not well constrained and
arise from what appear to be fundamentally flawed data sets. With the
addition of the images proposed here to our current sample of ACS
images, we will be able to extend our determinations of the black hole
mass- bulge luminosity and black hole mass-bulge mass relationships
for AGNs by an order of magnitude and test our preliminary results for
these fundamentally important relationships against those previously
determined for quiescent galaxies.

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 11908

Cycle 17: UVIS Bowtie Monitor

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.


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