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Daily Report #4447



 
 
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Old September 14th 07, 04:11 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report #4447

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 # 4447

PERIOD COVERED: UT September 13, 2007 (DOY 256)

OBSERVATIONS SCHEDULED

ACS/SBC WFPC2 11175

UV Imaging to Determine the Location of Residual Star Formation in Galaxies
Recently Arrived on the Red Sequence

We have identified a sample of low-redshift {z = 0.04 - 0.10} galaxies that
are candidates for recent arrival on the red sequence. They have red optical
colors indicative of old stellar populations, but blue UV-optical colors
that could indicate the presence of a small quantity of continuing or very
recent star formation. However, their spectra lack the emission lines that
characterize star-forming galaxies. We propose to use ACS/SBC to obtain
high- resolution imaging of the UV flux in these galaxies, in order to
determine the spatial distribution of the last episode of star formation.
WFPC2 imaging will provide B, V, and I photometry to measure the main
stellar light distribution of the galaxy for comparison with the UV imaging,
as well as to measure color gradients and the distribution of interstellar
dust. This detailed morphological information will allow us to investigate
the hypothesis that these galaxies have recently stopped forming stars and
to compare the observed distribution of the last star formation with
predictions for several different mechanisms that may quench star formation
in galaxies.

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.

NIC3 11107

Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation
in the Early Universe

We have used the ultraviolet all-sky imaging survey currently being
conducted by the Galaxy Evolution Explorer {GALEX} to identify for the first
time a rare population of low- redshift starbursts with properties
remarkably similar to high-redshift Lyman Break Galaxies {LBGs}. These
"compact UV luminous galaxies" {UVLGs} resemble LBGs in terms of size, SFR,
surface brightness, mass, metallicity, kinematics, dust, and color. The UVLG
sample offers the unique opportunity of investigating some very important
properties of LBGs that have remained virtually inaccessible at high
redshift: their morphology and the mechanism that drives their star
formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS in order
to 1} characterize their morphology and look for signs of interactions and
mergers, and 2} probe their star formation histories over a variety of
timescales. The images show a striking trend of small-scale mergers turning
large amounts of gas into vigorous starbursts {a process referred to as
dissipational or "wet" merging}. Here, we propose to complete our sample of
31 LBG analogs using the ACS/SBC F150LP {FUV} and WFPC2 F606W {R} filters in
order to create a statistical sample to study the mechanism that triggers
star formation in UVLGs and its implications for the nature of LBGs.
Specifically, we will 1} study the trend between galaxy merging and SFR in
UVLGs, 2} artificially redshift the FUV images to z=1-4 and compare
morphologies with those in similarly sized samples of LBGs at the same
rest-frame wavelenghts in e.g. GOODS, UDF, and COSMOS, 3} determine the
presence and morphology of significant stellar mass in "pre-burst" stars,
and 4} study their immediate environment. Together with our Spitzer
{IRAC+MIPS}, GALEX, SDSS and radio data, the HST observations will form a
unique union of data that may for the first time shed light on how the
earliest major episodes of star formation in high redshift galaxies came
about. This proposal was adapted from an ACS HRC+WFC proposal to meet the
new Cycle 16 observing constraints, and can be carried out using the ACS/SBC
and WFPC2 without compromising our original science goals.

NIC3 11335

NICMOS Defocus parameter test

This proposal tests the new NICMOS non-nominal focus positions, which are
implemented in the front-end systems and are specified in the Phase II using
the CAMERA-FOCUS=DEFOCUS Optional Parameter. The targets from Proposals 9832
and 11063 are used in this Proposal. The GO Proposal 9832 is an example of
how GOs may use the new non-nominal focus implementation for detector 3.
Proposal 11063 is the NICMOS focus monitor, which will be used to verify the
non-nominal focus for all 3 detectors.

S/C 11163

Accreting Pulsating White Dwarfs in Cataclysmic Variables

Recent ground-based observations have increased the number of known
pulsating white dwarfs in close binaries with active mass transfer
{cataclysmic variables} from 5 to 11 systems. Our past Cycles 8 and 11 STIS
observations of the first 2 known, followed by our Cycle 13 SBC observations
of the next 3 discovered, revealed the clear presence of the white dwarf and
increased amplitude of the pulsations in the UV compared to the optical. The
temperatures derived from the UV spectra show 4 systems are much hotter than
non- interacting pulsating white dwarfs. A larger sample is needed to sort
out the nature of the instability strip in accreting pulsators i.e. whether
effects of composition and rotation due to accretion result in a
well-defined instability strip as a function of Teff.

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.

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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