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Daily Rpt #4456



 
 
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Old September 27th 07, 02:30 PM posted to sci.astro.hubble
Bassford, Lynn
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Posts: 44
Default Daily Rpt #4456

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****** # 4456

PERIOD COVERED: UT September 26, 2007 (DOY 269)

OBSERVATIONS SCHEDULED

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.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive
Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured
Universe

(uses ACS/SBC and WFPC2)

Deep near-infrared imaging provides the only avenue towards
understanding a host of astrophysical problems, including: finding
galaxies and AGN at z 7, the evolution of the most massive galaxies,
the triggering of star formation in dusty galaxies, and revealing
properties of obscured AGN. As such, we propose to observe 60 selected
areas of the GOODS North and South fields with NICMOS Camera 3 in the
F160W band pointed at known massive M 10^11 M_0 galaxies at z 2
discovered through deep Spitzer imaging. The depth we will reach {26.5
AB at 5 sigma} in H_160 allows us to study the internal properties of
these galaxies, including their sizes and morphologies, and to
understand how scaling relations such as the Kormendy relationship
evolved. Although NIC3 is out of focus and undersampled, it is
currently our best opportunity to study these galaxies, while also
sampling enough area to perform a general NIR survey 1/3 the size of
an ACS GOODS field. These data will be a significant resource,
invaluable for many other science goals, including discovering high
redshift galaxies at z 7, the evolution of galaxies onto the Hubble
sequence, as well as examining obscured AGN and dusty star formation
at z 1.5. The GOODS fields are the natural location for HST to
perform a deep NICMOS imaging program, as extensive data from space
and ground based observatories such as Chandra, GALEX, Spitzer, NOAO,
Keck, Subaru, VLT, JCMT, and the VLA are currently available for these
regions. Deep high-resolution near-infrared observations are the one
missing ingredient to this survey, filling in an important gap to
create the deepest, largest, and most uniform data set for studying
the faint and distant universe. The importance of these images will
increase with time as new facilities come on line, most notably WFC3
and ALMA, and for the planning of future JWST observations.

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 wavelengths 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.

WEPC2 11196

An Ultraviolet Survey of Luminous Infrared Galaxies in the Local
Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
Luminous Infrared Galaxies {LIRGs} are primarily interacting or
merging disk galaxies undergoing starbursts and creating/fueling
central AGN. We propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W}
UV imaging of a sample of 27 galaxies drawn from the complete IRAS
Revised Bright Galaxy Sample {RBGS} LIRGs sample and known, from our
Cycle 14 B and I-band ACS imaging observations, to have significant
numbers of bright {23 B 21 mag} star clusters in the central 30
arcsec. The HST UV data will be combined with previously obtained HST,
Spitzer, and GALEX images to {i} calculate the ages of the clusters as
function of merger stage, {ii} measure the amount of UV light in
massive star clusters relative to diffuse regions of star formation,
{iii} assess the feasibility of using the UV slope to predict the far-
IR luminosity {and thus the star formation rate} both among and within
IR-luminous galaxies, and {iv} provide a much needed catalog of
rest-frame UV morphologies for comparison with rest-frame UV images of
high-z LIRGs and Lyman Break Galaxies. These observations will achieve
the resolution required to perform both detailed photometry of compact
structures and spatial correlations between UV and redder wavelengths
for a physical interpretation our IRX-Beta results. The HST UV data,
combined with the HST ACS, Spitzer, Chandra, and GALEX observations of
this sample, will result in the most comprehensive study of luminous
starburst galaxies to date.

WFPC2 11105

The LBV progenitor of SN 2005gl - a new key to massive star evolution
puzzles

The currently accepted theory regarding the last stages of massive
star evolution maintains that the evolution of the envelope is coupled
to that of the stellar core. For this reason, very massive stars are
expected to shed their outer hydrogen envelopes before they develop
large iron cores, and ultimately, explode as core-collapse supernovae
{SNe}. It is therefore a strict prediction of current models that
massive stars {certainly those above ~40 solar mass} will explode as
hydrogen-poor SNe, i.e., of Types Ib and Ic. In particular, the class
of luminous blue variables {LBVs} such as eta-Carina, which are known
to be very massive {up to 100 solar masses and above} are expected to
lose their entire hydrogen envelopes prior to their ultimate
explosions as SNe. However, using pre-explosion HST/WFPC2 imaging of
the location of the recent hydrogen-rich type IIn SN 2005gl, we have
identified {Gal-Yam et al. 2007} its putative progenitor as a very
luminous point source {with absolute V magnitude of -10.2}. If this is
a single star, it must be an LBV from luminosity considerations {no
other stars are as luminous}. If our progenitor identification is
correct, at least in some cases, massive stars explode before losing
most of their hydrogen envelope, indicating the core and envelope are
decoupled, and requiring revision of stellar evolution theory. Here,
we propose a single-orbit HST observation of the location of SN 2005gl
designed to test whether the point source we identified as its LBV
progenitor has indeed disappeared {as expected from a single star} or
remained unchanged {as expected, e.g., if it is a compact star
cluster}. These data are the last observational ingredient required to
firmly establish {or refute} the explosion of an LBV as a type IIn SN,
with fundamental implications for the theory of massive star
evolution. Since the new data will be compared to pre-explosion WFPC2
images, this program is perfectly suited to be carried out with the
WFPC2 camera.

WFPC2/NIC2 11193

A comprehensive study of the low-mass stellar population in the
Galactic starburst region NGC 3603

NGC 3603, located in the Carina spiral arm, is one of the most
luminous giant HII regions in the Milky Way, and as such it is often
referred to as a prime template for extragalactic starbursts. While
previous studies were focusing on the high and intermediate mass
stellar content of the central starburst cluster, which powers the HII
region, the effects of the starburst environment with its large number
of ionizing O stars on the emerging low- mass population are unknown.
As the most nearby, most easily accessible starburst, NGC 3603
provides the best testbed to study the long-lived, low-mass stars
originating from a starburst environment. Taking advantage of the
large field of view and high sensitivity of WFPC2, we want to survey
the stellar population in an area of 10pc x 10pc {6' x 6'} down to a
mass limit of 0.2 to 0.5 Mo. This will enable us to derive the total
cluster mass, look for spatial variations in the initial mass
function, determine the age of the dispersed low-mass population in
the HII region and search for evidence of sequential star formation.
Ultimately, we aim at reconstructing the low-mass stellar initial mass
function of the starburst epoch in NGC 3603, which in turn will
advance our understanding of extragalactic starburst phenomena and the
emerging low-mass stars as observed in ancient populations. The
observations of NGC 3603 are part of our larger effort to study
intense star-forming regions in the Milky Way, LMC and SMC.

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************** 08**************** 08
OBAD with Maneuver 28**************** 28

SIGNIFICANT EVENTS: (None)


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