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Daily #4074



 
 
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Old March 28th 06, 06:26 PM posted to sci.astro.hubble
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Default Daily #4074

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4074

PERIOD COVERED: UT March 20, 2006 (DOY 079)

OBSERVATIONS SCHEDULED

ACS/HRC/WFC 10729

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period Oct, 2 2005- May, 29-2006. The
second half of the program has a different proposal number: 10758.

ACS/WFC 10491

A Snapshot Survey of the most massive clusters of galaxies

We propose a snapshot survey of a sample of 124 high X-ray luminosity
clusters in the redshift range 0.3-0.7. Similarly luminous clusters at
these redshifts frequently exhibit strong gravitational lensing. The
proposed observations will provide important constraints on the nature
of the cluster mass distributions and a set of optically bright,
lensed galaxies for further 8-10m spectroscopy. We acknowledge the
broad community interest in this sample and waive our data rights for
these observations.

ACS/WFC 10524

Blue Stragglers: a key stellar population to probe internal cluster
dynamics

This proposal is part of a coordinated project devoted to understand
the interplay of globular cluster {GC} dynamics and the formation and
evolution of blue straggler stars {BSS}. By using a combination of HST
and ground-based observations we are constructing complete BSS surveys
in a sample of GCs; complete BSS surveys require mid-UV HST
observations in the center and wide field CCD ground based
observations under excellent seeing conditions of the exterior. Up to
now only four clusters have been surveyed in this way and the results
are surprising: in three GCs {M3, 47 Tuc, NGC 6752} we have discovered
that the BSS radial distribution is bimodal, highly peaked in the
cluster center, rapidly decreasing at intermediate radii and rising
again at large radii {Ferraro et al. 1997, 2004, Sabbi et al. 2004},
conversely BSS population in Omega Centauri does not show any
signature of the segregation which would be expected for a class of
objects arising from either stellar interactions or binarity {Ferraro
et al. 2005}. These observational facts are opening a new prospective
in the study of the formation processes and evolution of BSS in GCs.
By using extensive simulations, we demonstrated that the spatial
distribution of BSS observed in 47 Tuc can be only reproduced if a
sizable fraction of BSS is generated {via mass transfer in primordial
binaries} in the peripheral region of the cluster {Mapelli et al
2004}, thus excluding a purely collisional formation scenario. Here we
propose mid-UV imaging of a few clusters suspected of harboring a
large population of central BSS and a few known to have many BSS the
external region. These are good candidates for determining accurate
BSS radial distributions. The modest amount of time proposed here will
go far to determine the ubiquity of BSS bimodality and to constrain
models of dynamical evolution. Since we believe the proposed
observations would be useful to the entire stellar community {for
multifold purposes} we waive the propretary period.

ACS/WFC 10592

An ACS Survey of a Complete Sample 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 enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
ACS/WFC imaging of a complete sample of 88 L_IR 10^11.4 L_sun
luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample
{RBGS: i.e., 60 micron flux density 5.24 Jy}. This sample is ideal
not only in its completeness and sample size, but also in the
proximity and brightness of the galaxies. The superb sensitivity,
resolution, and field of view of ACS/WFC on HST enables a unique
opportunity to study the detailed structure of galaxies that sample
all stages of the merger process. Imaging will be done with the F439W
and F814W filters {B and I-band} to examine as a function of both
luminosity and merger state {i} the evidence at optical wavelengths of
star formation and AGN activity and the manner in which instabilities
{bars and bridges} in the galaxies may funnel material to these active
regions, {ii} the relationship between star formation and AGN
activity, and {iii} the structural properties {AGN, bulge, and disk
components} and fundamental parameters {effective radius and surface
brightness} of LIRGs and their similarity with putative evolutionary
byproducts {elliptical, S0 and classical AGN host galaxies}. This HST
survey will also bridge the wavelength gap between a Spitzer imaging
survey {covering seven bands in the 3.6-160 micron range} and a GALEX
UV imaging survey of these galaxies, but will resolve complexes of
star clusters and multiple nuclei at resolutions well beyond the
capabilities of either Spitzer or GALEX. The combined datasets will
result in the most comprehensive multiwavelength study of interacting
and merging galaxies to date.

ACS/WFC 10605

Quantifying Star Formation and Feedback: The M81 Group Dwarf Galaxies

Studies of the impact of star formation via stellar winds and
supernovae {'feedback'} on the properties of a galaxy are of
fundamental importance to understanding galaxy evolution. One crucial
aspect in these studies is a precise census of the recent star
formation in a galaxy. The aim of this proposal is to obtain spatially
resolved star formation histories with a time resolution of roughly 30
Myr over the last 500 Myr in a carefully designed sample using the
absolutely unique capabilities of the ACS. Our sample comprises 10
galaxies in the M81 group which is host to a wide diversity of dwarf
star forming galaxies. They span ranges of 6 magnitudes in luminosity,
1000 in current star formation rate, and 0.5 dex in metallicity. The
ACS observations will allow us to directly observe the strength and
spatial relationships of all of the star formation in these galaxies
in the last 500 Myr. We can then quantify the star formation and
measure {1} the fraction of star formation that is triggered by
feedback, {2} the fraction of star formation that occurs in clusters
and associations, and {3} to what degree future star formation is
governed by the feedback from previous star formation. The ACS
observations will be complemented with high-quality ancillary data
collected by our team for all galaxies {e.g., Spitzer, UV/optical/NIR,
VLA HI}. We will calculate the energy created by star formation events
and compare it to the estimated energy deposited into the local ISM.
This will enable us to construct prescriptions of how star formation
and feedback depend on metallicity, size, gas content, and current
star formation rates in galaxies. Our resolved star formation maps
will be compared with star formation rates inferred from H-alpha, UV,
and IR observations - allowing an independent calibration of these
techniques. Recent ACS imaging by us of one galaxy in the same group
clearly demonstrates the feasibility of the proposed program. Most of
the sample galaxies are located in the CVZ, making this an extremely
efficient program.

ACS/WFC/WFPC2 10584

The link between X-ray source and stellar populations in M81

We propose to perform a deep v~26-27.0 HST-ACS survey of the nearby
{3.6 Mpc} spiral galaxy M~81 in order to study the nature of its X-ray
source populations detected with Chandra. For the first time in a
galaxy other than the Milky-Way or the Magelanic Clouds, we will
classify X-ray sources as High-Mass and Low-Mass X-ray binaries
{HMXBs, LMXBs} and investigate how these populations depend on their
galactic environment. The classification will be performed {a} by
finding and classifying unique optical counterparts for the X-ray
sources and {b} studying the stellar populations in their vicinity.
Both tasks require the 0.1'' resolution of HST-ACS which matches well
the positional accuracy of Chandra. Finally we will use these results
together with X-ray binary evolution synthesis models in order to
constrain X-ray binary {XRB} evolution channels. These data will also
be a great resource for studies of the star-formation and star-
cluster populations in one of the prototypical spiral galaxies.

FGS 10757

Monitoring FGS1r's Interferometric Response as a Function of Spectral
Color

This proposal obtains reference point source Transfer Functions
{S-Curves} for FGS1r through the F583W filter and the F5ND attenuator
at the center position of the FGS1r FOV for a variety of stars of
different spectral types. These Transfer Functions are needed to
support the analysis of GO science data for the study of close and
wide binary star systems and for determining the angular size and
shape of extended sources. This proposal observes stars that have been
observed in previous cycles to monitor the long term evolution of the
FGS1r S-curves. This proposal also {1} monitors the FGS1r Lateral
Color response {using stars Latcol-A and Latcol-B}, {2} calibrates the
"Pos/Trans" bias of a star's position as determined from Transfer mode
and Position mode observations, and {3} calibrates the shift of a
star's centroid when observed with F5ND relative to that when observed
with F583W.

NIC2 10527

Imaging Scattered Light from Debris Disks Discovered by the Spitzer
Space Telescope Around 20 Sun-like Stars

We propose to use the high contrast capability of the NICMOS
coronagraph to image a sample of newly discovered circumstellar disks
associated with sun-like stars. These systems were identified by their
strong thermal infrared emission with the Spitzer Space Telescope as
part of the Spitzer Legacy Science program titled, "The Formation and
Evolution of Planetary Systems {FEPS}." Modelling of the thermal
excess emission in the form of spectral energy distributions alone
cannot distinguish between narrowly confined high opacity disks and
broadly distributed, low opacity disks. However, our proposed NICMOS
observations can, by imaging the light scattered from this material.
Even non- detections will place severe constraints on the disk
geometry, ruling out models with high optical depth. Unlike previous
disk imaging programs, our program contains a well defined sample of
solar mass stars covering a range of ages from ~10Myrs to a few Gyrs,
allowing us to study the evolution of disks from primordial to debris
for the first time. These results will greatly improve our
understanding of debris disks around Sun- like stars at stellar ages
nearly 10x older than any previous investigation. Thus we will have
fit a crucial piece into the puzzle concerning the formation and
evolution of our own solar system.

WFPC2 10749

Earth Flats

This proposal monitors flatfield stability. This proposal obtains
sequences of Earth streak flats to construct high quality flat fields
for the WFPC2 filter set. These flat fields will allow mapping of the
OTA illumination pattern and will be used in conjuction with previous
internal and external flats to generate new pipeline superflats. These
Earth flats will complement the Earth flat data obtained during cycles
4-13.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10177 - GSAcq(1,3,1) results in finelock backup (3,0,3) due to scan
step limit exceeded on FGS-1 @ 079/1737z

The GSAcq(1,3,1) scheduled at 079/17:37:17 - 17:44:54 resulted in
finelock backup (3,0,3) using FGS-3, due to scan step limit exceeded
on FGS-1. Pre-acquisition OBADs were successful. OBAD2 at 079/17:32:47
had total attitude correction (RSS) value of 15.02 arcseconds.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 11 11
FGS REacq 03 03
OBAD with Maneuver 23 23

SIGNIFICANT EVENTS: (None)

 




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