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Daily Report #4507

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Old December 14th 07, 06:02 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report #4507

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** # 4507

PERIOD COVERED: UT December 13, 2007 (DOY 347)


ACS/SBC 11215

New Sightlines for the Study of Intergalactic Helium: Dozens of
High-Confidence, UV- Bright Quasars from SDSS/GALEX

The reionization of IGM helium is thought to have occurred at
redshifts of z=3 to 4. Detailed study of HeII Lyman-alpha absorption
toward a handful of QSOs at 2.7z3.3 demonstrated the high potential
of such IGM probes, but the critically small sample size limits
confidence in cosmological inferences. The requisite unobscured
sightlines to high-z are extremely rare, but SDSS provides 5800, z3.1
QSOs potentially suitable for HeII studies. We've cross-correlated
SDSS quasars with GALEX UV sources to obtain dozens of new, high
confidence, candidate sightlines {z=3.1-4.9} potentially useful for
detailed HeII studies with HST. We propose brief, 2-orbit
reconnaissance ACS SBC prism exposures toward each of the best dozen
new quasars, to definitively verify UV flux down to HeII. Our combined
SDSS/GALEX selection insures a high confirmation rate, as the quasars
are already known to be UV bright in GALEX. Our program will provide a
statistical sample of HeII sightlines extending to high redshift,
enabling future long exposure follow-up spectra with the SBC prism, or
superb quality COS or STIS spectra after SM4. Stacks of our prism
spectra will also directly yield ensemble information. Ultimately, the
new sightlines will enable confident measures of the spectrum and
evolution of the ionizing background, the evolution of HeII opacity,
the epoch of helium reionization, and the density of IGM baryons.

FGS 11317

HST Cycle 16 & pre-SM4 FGS alignment check

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be non-
standard reference files available to users with a USEAFTER date/time
mark. The keyword 'USEAFTER=date/time' will also be added to the
header of each POST-SAA DARK frame. The keyword must be populated with
the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science i mages. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC2/NIC1 11000

Evaporating Disks

Evaporation in the vicinity of an O star disrupts protoplanetary
disks, as seen in the Orion proplyds. We have found a number of
evaporating disks with Spitzer, which are in some ways more dramatic
and better oriented for detailed study than the proplyds ? they have
cometary tails extending up to 0.1 pc from the evaporation working
surface. We will use Spitzer/IRS and HST/NICMOS to investigate these
systems in more detail. We want to explore the excitation condition in
the gas, both in the head and in the tail where possible. We will
measure the effects of evaporation on the characteristic emission
features of the dust. We also will use NICMOS to image them in detail,
including mapping complex structures resolved in their tails at 24

WFPC2 10884

The Dynamical Structure of Ellipticals in the Coma and Abell 262

We propose to obtain images of 13 relatively luminous early type
galaxies in the Coma cluster and Abell 262 for which we have already
collected ground based major and minor axis spectra and images. The
higher resolution HST images will enable us to study the central
regions of these galaxies which is crucial to our dynamical modeling.
The complete data set will allow us to perform a full dynamical
analysis and to derive the dark matter content and distribution, the
stellar orbital structure, and the stellar population properties of
these objects, probing the predictions of galaxy formation models. The
dynamical analysis will be performed using an up-to-date axi-symmetric
orbit superposition code.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and
highly non-uniform archive, making comprehensive comparative studies
among galaxies essentially impossible. We propose to secure HST's
lasting impact on the study of nearby galaxies by undertaking a
systematic, complete, and carefully crafted imaging survey of ALL
galaxies in the Local Universe outside the Local Group. The resulting
images will allow unprecedented measurements of: {1} the star
formation history {SFH} of a 100 Mpc^3 volume of the Universe with a
time resolution of Delta[log{t}]=0.25; {2} correlations between
spatially resolved SFHs and environment; {3} the structure and
properties of thick disks and stellar halos; and {4} the color
distributions, sizes, and specific frequencies of globular and disk
clusters as a function of galaxy mass and environment. To reach these
goals, we will use a combination of wide-field tiling and pointed deep
imaging to obtain uniform data on all 72 galaxies within a
volume-limited sample extending to ~3.5 Mpc, with an extension to the
M81 group. For each galaxy, the wide-field imaging will cover out to
~1.5 times the optical radius and will reach photometric depths of at
least 2 magnitudes below the tip of the red giant branch throughout
the limits of the survey volume. One additional deep pointing per
galaxy will reach SNR~10 for red clump stars, sufficient to recover
the ancient SFH from the color-magnitude diagram. This proposal will
produce photometric information for ~100 million stars {comparable to
the number in the SDSS survey} and uniform multi- color images of half
a square degree of sky. The resulting archive will establish the
fundamental optical database for nearby galaxies, in preparation for
the shift of high- resolution imaging to the near-infrared.


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

HSTARS: (None)


18163-2 - RMGA Calibration for December 2007


*********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 11***************** 11
FGS REacq************** 05***************** 05
OBAD with Maneuver **** 32***************** 32


OPS Request 18163 was successfully executed on December 13, 2007 to
perform an RMGA Calibration test. RMGA was powered on at GMT
347/22:00. PSEA testmode was executed from GMT 347/23:12 to 347/23:42
to collect RMGA analog drift rate data for bias estimates. This data
collection period was about 30 minutes (15 iterations of PSEA
testmode) and will be processed by SAC. Assessment will determine if
the drift rates have changed enough to warrant a bias update in PSEA
configuration memory.


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