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Daily Report #5104



 
 
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Old May 26th 10, 01:24 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5104

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5104

PERIOD COVERED: 5am May 25 - 5am May 26, 2010 (DOY 145/09:00z-146/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 06 06
FGS REAcq 09 09
OBAD with Maneuver 05 05

SIGNIFICANT EVENTS: (None)



OBSERVATIONS SCHEDULED:

ACS/WFC 11995

CCD Daily Monitor (Part 2)

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.

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/COS/NUV 11579

The Difference Between Neutral- and Ionized-Gas Metal Abundances in
Local Star-Forming Galaxies with COS

The metallicity of galaxies and its evolution with redshift is of
paramount importance for understanding galaxy formation. Abundances in
the interstellar medium (ISM) are typically determined using
emission-line spectroscopy of HII regions. However, since HII regions
are associated with recent SF they may not have abundances typical for
the galaxy as a whole. This is true in particular for star-forming
galaxies (SFGs), in which the bulk of the metals may be contained in
the neutral gas. It is therefore important to directly probe the metal
abundances in the neutral gas. This can be done using absorption lines
in the Far UV. We have developed techniques to do this in SFGs, where
the absorption is measured for sightlines toward bright SF regions
within the galaxy itself. We have successfully applied this technique
to a sample of galaxies observed with FUSE. The results have been very
promising, suggesting in I Zw 18 that abundances in the neutral gas
may be up to 0.5 dex lower than in the ionized gas. However, the
interpretation of the FUSE data is complicated by the very large FUSE
aperture (30 arcsec), the modest S/N, and the limited selection of
species available in the FUSE bandpass. The advent of COS on HST now
allows a significant advance in all of these areas. We will therefore
obtain absorption line spectroscopy with G130M in the same sample for
which we already have crude constraints from FUSE. We will obtain
ACS/SBC images to select the few optimal sightlines to target in each
galaxy. The results will be interpreted through line-profile fitting
to determine the metal abundances constrained by the available lines.
The results will provide important new insights into the metallicities
of galaxies, and into outstanding problems at high redshift such as
the observed offset between the metallicities of Lyman Break Galaxies
and Damped Lyman Alpha systems.

COS/FUV/COS/NUV 11601

UV spectroscopy of the hot bare stellar core H1504+65

H1504+65 is the hottest known white dwarf (Teff=200, 000 K). It has an
extraordinary surface composition. The surface is devoid of hydrogen
and helium. It is mainly composed of carbon and oxygen (by equal
amounts) and neon (2%). We obviously see the exposed core of a former
red giant. The evolutionary history of this unique object is unknown.
We have identified magnesium absorption lines in the soft X-ray
photospheric Chandra spectrum, which suggests that H1504+65 may be an
O-Ne-Mg white dwarf. We will test this hypothesis by abundance
determinations of Mg and Na. If confirmed, then H1504+65 would be the
most compelling case for the existence of single O-Ne-Mg white dwarfs.

COS/FUV/COS/NUV 11741

Probing Warm-Hot Intergalactic Gas at 0.5 z 1.3 with a Blind
Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems

Currently we can only account for half of the baryons (or less)
expected to be found in the nearby universe based on D/H and CMB
observations. This "missing baryons problem" is one of the
highest-priority challenges in observational extragalatic astronomy.
Cosmological simulations suggest that the baryons are hidden in
low-density, shock-heated intergalactic gas in the log T = 5 - 7
range, but intensive UV and X-ray surveys using O VI, O VII, and O
VIII absorption lines have not yet confirmed this prediction. We
propose to use COS to carry out a sensitive survey for Ne VIII and Mg
X absorption in the spectra of nine QSOs at z(QSO) 0.89. For the
three highest-redshift QSOs, we will also search for Si XII. This
survey will provide more robust constraints on the quantity of baryons
in warm-hot intergalactic gas at 0.5 z 1.3, and the data will
provide rich constraints on the metal enrichment, physical conditions,
and nature of a wide variety of QSO absorbers in addition to the
warm-hot systems. By comparing the results to other surveys at lower
redshifts (with STIS, FUSE, and from the COS GTO programs), the
project will also enable the first study of how these absorbers evolve
with redshift at z 1. By combining the program with follow-up galaxy
redshift surveys, we will also push the study of galaxy-absorber
relationships to higher redshifts, with an emphasis on the
distribution of the WHIM with respect to the large-scale matter
distribution of the universe..

COS/NUV 11520

COS-GTO: QSO Absorbers, Galaxies and Large-scale Structures in the
Local Universe.

This is a program to probe the large scale structure of baryons in the
universe, including addressing questions of baryon fraction, physical
conditions and relationships between absorbers and large-scale
structures of galaxies. Besides these specific goals, this proposed
GTO program also probes a large enough total path length in Ly alpha
and OVI to add significantly to what STIS/FUSE has already observed.
Several Galactic High Velocity Cloud Complexes also are probed by
these sightlines, particularly the M Complex. The total path length of
this proposed program for Ly alpha large-scale structure surveys is
delta_z~5.5.

We have selected a variety of targets to address these questions,
under the following subcategories:

1. Target 8 bright BL Lac objects to search for low contrast Ly alpha
absorbers from the warm-hot interstellar medium (WHIM). Science
drivers: What are physical conditions and extent of warm-hot IGM in
the current epoch? Can we discover metal-poor WHIM using very broad Ly
alpha lines? What is the number density of such lines (dN/dz) and what
is their relationship if any with tentative Chandra detections of even
hotter gas?

2. Ly alpha cloud sizes: The targets are a bright AGN pair which yield
tangential distance separations of 100--500 kpc at z=0.01--0.05, where
galaxy surveys are excellent. This pair has two filaments and two
voids in this distance range. Science drivers: What are the
characteristic sizes of Ly alpha absorbers, weak metal-line absorbers
and absorbers in voids? Better size determinations will tighten
current estimates of the baryon content of the photoionzed IGM .

3. Probes of starburst outflows: The targets are bright AGN, = 100
kpc in projection out of the minor axis of nearby starburst galaxies.
Science drivers: Outflowing, unbound winds have been implicated as a
primary mechanism to enrich the IGM in mass, metals and energy. But do
starburst winds from massive galaxies escape the galaxy's
gravitational potential? If so, what is the metallicity and what are
mass outflow rates of these winds?

4. A large galaxy's gaseous halo: Three probes of the kinematics and
metallicity of a single L* galaxy halo. These observations includes
G130M, G160M exposures at SNR~20 and G285M at 2850A and SNR~10 for
MgII. The 2L* galaxy, ESO 157-G049 (cz=1678 km/s), being probed by
these sightlines has an available H I 21cm map from ATCA, H alpha
imaging from CTIO and long-slit spectra from MSSSO. Science drivers:
What are the extent, metallicity, ionization conditions and kinematics
of gaseous halos of normal luminous (L*) galaxies? Is there evidence
for outflow, inflow or galactic fountain circulation of gas in massive
galaxy halos? What is the source of halo gas (outflowing winds,
infalling metal-poor gas from stripping of nearby dwarf galaxies,
nuclear outflows, large numbers of bound dark matter halos??) and what
is the relationship between this gas and Galactic high-velocity clouds
(HVCs)?

5. Dwarf galaxy

COS/NUV 11894

NUV Detector Dark Monitor

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.

S/C/WFC3/IR 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).

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 11855

STIS/CCD Spectroscopic Sensitivity Monitor for Cycle 17

Monitor sensitivity of each CCD grating mode to detect any change due
to contamination or other causes.

WFC3/IR 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond
the current redshift frontier. Here we propose a pure parallel program
using this new instrument to search for Lyman-break galaxies at
6.5z8.8 and to probe the epoch of reionization, a hallmark event in
the history of the early universe. We request 200 orbits, spreading
over 30 ~ 50 high Galactic latitude visits (|b|20deg) that last for 4
orbits and longer, resulting a total survey area of about 140~230
square arcminute. Based on our understanding of the new HST parallel
observation scheduling process, we believe that the total number of
long-duration pure parallel visits in Cycle 17 should be sufficient to
accommodate our program. We waive all proprietary rights to our data,
and will also make the enhanced data products public in a timely
manner. (1) We will use both the UVIS and the IR channels, and do not
need to seek optical data from elsewhere. (2) Our program will likely
triple the size of the probable candidate samples at z~7 and z~8, and
will complement other targeted programs aiming at the similar redshift
range. (3) Being a pure parallel program, our survey will only make
very limited demand on the scarce HST resources. More importantly, as
the pure parallel pointings will be at random sight-lines, our program
will be least affected by the bias due to the large scale structure
("cosmic variance"). (4) We aim at the most luminous LBG population,
and will address the bright-end of the luminosity function at z~8 and
z~7. We will constrain the value of L* in particular, which is
critical for understanding the star formation process and the stellar
mass assembly history in the first few hundred million years of the
universe. (5) The candidates from our survey, most of which will be
the brightest ones that any surveys would be able to find, will have
the best chance to be spectroscopically confirmed at the current
8--10m telescopes. (6) We will also find a large number of extremely
red, old galaxies at intermediate redshifts, and the fine spatial
resolution offered by the WFC3 will enable us constrain their
formation history based on the study of their morphology, and hence
shed light on their connection to the very early galaxies in the
universe.

WFC3/IR 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF),
and calibrate the SBF distance method, in the F110W and F160W filters
of the Wide Field Camera 3 IR channel. Because of the very high
throughput of F110W and the good match of F160W to the standard H
band, we anticipate that both of these filters will be popular choices
for galaxy observations with WFC3/IR. The SBF signal is typically an
order of magnitude brighter in the near-IR than in the optical, and
the characterisitics (sensitivity, FOV, cosmetics) of the WFC3/IR
channel will be enormously more efficient for SBF measurements than
previously available near-IR cameras. As a result, our proposed SBF
calibration will allow accurate distance derivation whenever an
early-type or bulge-dominated galaxy is observed out to a distance of
150 Mpc or more (i.e., out to the Hubble flow) in the calibrated
passbands. For individual galaxy observations, an accurate distance is
useful for establishing absolute luminosities, black hole masses,
linear sizes, etc. Eventually, once a large number of galaxies have
been observed across the sky with WFC3/IR, this SBF calibration will
enable accurate mapping of the total mass density distribution in the
local universe using the data available in the HST archive. The
proposed observations will have additional important scientific value;
in particular, we highlight their usefulness for understanding the
nature of multimodal globular cluster color distributions in giant
elliptical galaxies.

WFC3/UVI 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond
the current redshift frontier. Here we propose a pure parallel program
using this new instrument to search for Lyman-break galaxies at
6.5z8.8 and to probe the epoch of reionization, a hallmark event in
the history of the early universe. We request 200 orbits, spreading
over 30 ~ 50 high Galactic latitude visits (|b|20deg) that last for 4
orbits and longer, resulting a total survey area of about 140~230
square arcminute. Based on our understanding of the new HST parallel
observation scheduling process, we believe that the total number of
long-duration pure parallel visits in Cycle 17 should be sufficient to
accommodate our program. We waive all proprietary rights to our data,
and will also make the enhanced data products public in a timely
manner. (1) We will use both the UVIS and the IR channels, and do not
need to seek optical data from elsewhere. (2) Our program will likely
triple the size of the probable candidate samples at z~7 and z~8, and
will complement other targeted programs aiming at the similar redshift
range. (3) Being a pure parallel program, our survey will only make
very limited demand on the scarce HST resources. More importantly, as
the pure parallel pointings will be at random sight-lines, our program
will be least affected by the bias due to the large scale structure
("cosmic variance"). (4) We aim at the most luminous LBG population,
and will address the bright-end of the luminosity function at z~8 and
z~7. We will constrain the value of L* in particular, which is
critical for understanding the star formation process and the stellar
mass assembly history in the first few hundred million years of the
universe. (5) The candidates from our survey, most of which will be
the brightest ones that any surveys would be able to find, will have
the best chance to be spectroscopically confirmed at the current
8--10m telescopes. (6) We will also find a large number of extremely
red, old galaxies at intermediate redshifts, and the fine spatial
resolution offered by the WFC3 will enable us constrain their
formation history based on the study of their morphology, and hence
shed light on their connection to the very early galaxies in the
universe.

WFC3/UVI 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 biasBRand dark frames. A smaller set of
2Kx4K subarray biases are acquired at less frequent
intervalsBRthroughout the cycle to support subarray science
observations. The internals from this proposal,BRalong with those
from the anneal procedure (11909), will be used to generate the
necessary superbiasBRand superdark reference files for the
calibration pipeline (CDBS).

WFC3/UVI 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate
new hot pixels. This proposal performs the procedure required for
repairing those hot pixels in the UVIS CCDs. During an anneal, the
two-stage thermo-electric cooler (TEC) is turned off and the
four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20C.
As a result of the CCD warmup, a majority of the hot pixels will be
fixed; previous instruments such as WFPC2 and ACS have seen repair
rates of about 80%. Internal UVIS exposures are taken before and after
each anneal, to allow an assessment of the procedure's effectiveness
in WFC3, provide a check of bias, global dark current, and hot pixel
levels, as well as support hysteresis (bowtie) monitoring and CDBS
reference file generation. One IR dark is taken after each anneal, to
provide a check of the IR detector.

 




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