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Daily Report #4454



 
 
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Old September 25th 07, 05:05 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4454

Notice: Due to the conversion of some ACS WFC or HRC observations into
WFPC2, or NICMOS observations after the loss of ACS CCD science capability
in January, there may be an occasional discrepancy between a proposal's
listed (and correct) instrument usage and the abstract that follows it.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4454

PERIOD COVERED: UT September 24, 2007 (DOY 267)

OBSERVATIONS SCHEDULED

ACS/SBC 10872

Lyman Continuum Emission in Galaxies at z=1.2

Lyman continuum photons produced in massive starbursts may have played a
dominant role in the reionization of the Universe. Starbursts are important
contributors to the ionizing metagalactic background at lower redshifts as
well. However, their contribution to the background depends upon the
fraction of ionizing radiation that escapes from the intrinsic opacity of
galaxies below the Lyman limit. Current surveys suggest escape fractions of
a few percent, up to 10%, with very few detections {as opposed to upper
limits} having been reported. No detections have been reported in the epochs
between z=0.1 and z=2. We propose to measure the fraction of escaping Lyman
continuum radiation from 15 luminous z~1.2 galaxies in the GOODS fields.
Using the tremendous sensitivity of the ACS Solar- blind Channel, we will
reach AB=30 mag., allowing us to detect an escape fraction of 1%. We will
correlate the amount of escaping radiation with the photometric and
morphological properties of the galaxies. A non-detection in all sources
would imply that QSOs provide the overwhelming majority of ionizing
radiation at z=1.3, and it would strongly indicate that the properties of
galaxies at higher redshift have to be significantly different for galaxies
to dominate reionization. The deep FUV images will also be useful for
extending the FUV study of other galaxies in the GOODS fields.

WFPC2 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A variety of
internal exposures are obtained in order to provide a monitor of the
integrity of the CCD camera electronics in both bays {both gain 7 and gain
15 -- to test stability of gains and bias levels}, a test for quantum
efficiency in the CCDs, and a monitor for possible buildup of contaminants
on the CCD windows. These also provide raw data for generating annual
super-bias reference files for the calibration pipeline.

NIC1 10889

The Nature of the Halos and Thick Disks of Spiral Galaxies

We propose to resolve the extra-planar stellar populations of the thick
disks and halos of seven nearby, massive, edge-on galaxies using ACS,
NICMOS, and WFPC2 in parallel. These observations will provide accurate star
counts and color-magnitude diagrams 1.5 magnitudes below the tip of the Red
Giant Branch sampled along the two principal axes and one intermediate axis
of each galaxy. We will measure the metallicity distribution functions and
stellar density profiles from star counts down to very low average surface
brightnesses, equivalent to ~32 V-mag per square arcsec. These observations
will provide the definitive HST study of extra-planar stellar populations of
spiral galaxies. Our targets cover a range in galaxy mass, luminosity, and
morphology and as function of these galaxy properties we will provide: - The
first systematic study of the radial and isophotal shapes of the diffuse
stellar halos of spiral galaxies - The most detailed comparative study to
date of thick disk morphologies and stellar populations - A comprehensive
analysis of halo and thick disk metallicity distributions as a function of
galaxy type and position within the galaxy. - A sensitive search for tidal
streams - The first opportunity to directly relate globular cluster systems
to their field stellar population We will use these fossil records of the
galaxy assembly process preserved in the old stellar populations to test
halo and thick disk formation models within the hierarchical galaxy
formation scheme. We will test LambdaCDM predictions on sub-galactic scales,
where it is difficult to test using CMB and galaxy redshift surveys, and
where it faces its most serious difficulties.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 DARKs. 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 images. Each observation will need its own CRMAP, as
different SAA passages leave different imprints on the NICMOS detectors.

NIC1/NIC3 10924

Constraints on the Assembly and Dynamical Masses of z~2 Galaxies

We propose deep NICMOS/NIC2 F160W imaging of seven star-forming galaxies at
z~2. These galaxies comprise an entirely unique sample, with not only
redshifts measured from optical and near-IR spectra, but also SINFONI/VLT
near-IR integral field spectroscopic measurements providing kinematic maps
of H-alpha emission out to radii of =10 kpc. We aim to determine the
dynamical masses and evolutionary states of these systems, as part of the
larger goal of understanding how mass is assembled in distant galaxies. In
order to interpret our novel H-alpha integral field maps in terms of mass,
we require detailed knowledge of the structural parameters of our target
objects at rest-frame optical wavelengths and on ~1 kpc scales. We want to
establish if the mass is distributed in a disk, bulge, or merging sub-units,
and if we can detect tidal features associated with a merger. F160W imaging
with NICMOS/NIC2 provides the perfect combination of sensitivity and
resolution to address these questions, and arrive at the fundamental
quantity: the dynamical mass.

WFPC2 11023

WFPC2 CYCLE 15 Standard Darks - part 1

This dark calibration program obtains dark frames every week in order to
provide data for the ongoing calibration of the CCD dark current rate, and
to monitor and characterize the evolution of hot pixels. Over an extended
period these data will also provide a monitor of radiation damage to the
CCDs.

WFPC2 11218

Snapshot Survey for Planetary Nebulae in Globular Clusters of the Local
Group

Planetary nebulae {PNe} in globular clusters {GCs} raise a number of
interesting issues related to stellar and galactic evolution. The number of
PNe known in Milky Way GCs, 4, is surprisingly low if one assumes that all
stars pass through a PN stage. However, it is likely that the remnants of
stars now evolving in Galactic GCs leave the AGB so slowly that any ejected
nebula dissipates long before the star becomes hot enough to ionize it. Thus
there should not be ANY PNe in Milky Way GCs--but there are four! It has
been suggested that these PNe are the result of mergers of binary stars
within GCs, i.e., that they are descendants of blue stragglers. The
frequency of occurrence of PNe in external galaxies poses more questions,
because it shows a range of almost an order of magnitude. I propose a
Snapshot survey aimed at discovering PNe in the GC systems of Local Group
galaxies more distant than the Magellanic Clouds. These clusters, some of
which may be much younger than their counterparts in the Milky Way, might
contain many more PNe than those of our own galaxy. I will use the standard
technique of emission-line and continuum imaging, which easily discloses
PNe.

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 08 08
FGS REacq 07 07
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)
 




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