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 # 4404
PERIOD COVERED: UT July 13,14,15, 2007 (DOY 194,195,196)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8793
NICMOS Post-SAA calibration - CR Persistence Part 4
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
images. Each observation will need its own CRMAP, as
different SAA
passages leave different imprints on the NICMOS detectors.
WFPC2 11178
Probing Solar System History with Orbits, Masses, and
Colors of
Transneptunian Binaries
The recent discovery of numerous transneptunian binaries
{TNBs} opens a
window into dynamical conditions in the protoplanetary
disk where they
formed as well as the history of subsequent events which
sculpted the
outer Solar System and emplaced them onto their present
day heliocentric
orbits. To date, at least 47 TNBs have been discovered,
but only about a
dozen have had their mutual orbits and separate colors
determined,
frustrating their use to investigate numerous important
scientific
questions. The current shortage of data especially
cripples scientific
investigations requiring statistical comparisons among the
ensemble
characteristics. We propose to obtain sufficient
astrometry and
photometry of 23 TNBs to compute their mutual orbits and
system masses
and to determine separate primary and secondary colors,
roughly tripling
the sample for which this information is known, as well as
extending it
to include systems of two near-equal size bodies. To make
the most
efficient possible use of HST, we will use a
optimally schedule our observations.
WFPC2 11175
UV Imaging to Determine the Location of Residual Star
Formation in
Galaxies Recently Arrived on the Red Sequence
We have indentified 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.
NIC2 11157
NICMOS Imaging Survey of Dusty Debris Around Nearby Stars
Across the
Stellar Mass Spectrum
Association of planetary systems with dusty debris disks
is now quite
secure, and advances in our understanding of planet
formation and
evolution can be achieved by the identification and
characterization of
an ensemble of debris disks orbiting a range of central
stars with
different masses and ages. Imaging debris disks in
starlight scattered
by dust grains remains technically challenging so that
only about a
dozen systems have thus far been imaged. A further advance
in this field
needs an increased number of imaged debris disks. However,
the technical
challege of such observations, even with the superb
combination of HST
and NICMOS, requires the best targets. Recent HST imaging
investigations
of debris disks were sample-limited not limited by the
technology used.
We performed a search for debris disks from a IRAS/Hipparcos
cross
correlation which involved an exhaustive background
contamination check
to weed out false excess stars. Out of ~140 identified
debris disks, we
selected 22 best targets in terms of dust optical depth
and disk angular
size. Our target sample represents the best currently
available target
set in terms of both disk brightness and resolvability.
For example, our
targets have higher dust optical depth, in general, than
newly
identified Spitzer disks. Also, our targets cover a wider
range of
central star ages and masses than previous debris disk
surveys. This
will help us to investigate planetary system formation and
evolution
across the stellar mass spectrum. The technical
feasibility of this
program in two-gyro mode guiding has been proven with
on-orbit
calibration and science observations during HST cycles 13,
14, and 15.
WFPC2 11079
Treasury Imaging of Star Forming Regions in the Local
Group:
Complementing the GALEX and NOAO Surveys
We propose to use WFPC2 to image the most interesting
star-forming
regions in the Local Group galaxies, to resolve their
young stellar
populations. We will use a set of filters including F170W,
which is
critical to detect and characterize the most massive
stars, to whose hot
temperatures colors at longer wavelengths are not
sensitive. WFPC2's
field of view ideally matches the typical size of the
star-forming
regions, and its spatial resolution allows us to measure
indvidual
stars, given the proximity of these galaxies. The
resulting H-R diagrams
will enable studies of star- formation properties in these
regions,
which cover largely differing metallicities {a factor of
17, compared to
the factor of 4 explored so far} and characteristics. The
results will
further our understanding of the star-formation process,
of the
interplay between massive stars and environment, the
properties of dust,
and will provide the key to interpret integrated
measurements of
star-formation indicators {UV, IR, Halpha} available for
several
hundreds more distant galaxies. Our recent deep surveys of
these
galaxies with GALEX {FUV, NUV} and ground-based imaging
{UBVRI, Halpha,
[OIII] and [SII]} provided the identification of the most
relevant SF
sites. In addition to our scientific analysis, we will
provide catalogs
of HST photometry in 6 bands, matched corollary
ground-based data, and
UV, Halpha and IR integrated measurements of the
associations, for
comparison of integrated star-formation indices to the
resolved
populations. We envisage an EPO component.
ACS/SBC/WFPC2 10904
Star formation in extended UV disk {XUV-disk} galaxies
The Galaxy Evolution Explorer {GALEX} has discovered the
existence of
extended UV-disk {XUV-disk} galaxies. This class of
intriguing spiral
galaxies is distinguished by UV-bright regions of star
formation located
at extreme galactocentric radii, commonly reaching many
times the
optical extent of each target. XUV-disks represent a
population of
late-type galaxies still actively building, or
significantly augmenting,
their stellar disk in the outer, low-density environment.
Prior to
GALEX, such regions were considered to be far more stable
against star
formation than now realized. Our work on these targets has
led to the
recognition of the XUV phenomenon as probing a diverse
population of
galaxies which, although having certain commonality in
terms of their
present XUV star formation, have apparently experienced
different star
formation histories {as judged by their outer disk
UV-optical colors and
morphology}. In ordinary spirals, disk formation occurred
at a much
earlier epoch, making today's XUV-disks useful templates
for
commonplace, high z galaxies. The diverse XUV-disks in our
sample may
represent snapshots of different phases in the disk
building process. We
seek to characterize the demographics of star forming
regions occupying
this environmental range, especially in contrast to their
inner disk
counterparts. HST imaging is needed to accurately
characterize the
massive stars and clusters which have, in fact, managed to
form. The
GALEX observations are limited by 5" resolution. Deep
ACS FUV, B, V, I,
and H-alpha imaging {along with parallel WFPC2 data} will
allow: {1}
photometric classification of the
the cluster mass function and age distribution, {3}
critical accounting
for possible leakage of Lyman continuum photons in a
porous ISM or an
IMF change, and {4} population synthesis modeling of the
field SFH on
Gyr timescales. We benefit from extensive archival HST
observations of
our target galaxies, although the outer disk has yet to be
probed.
WFPC2 10884
The Dynamical Structure of Ellipticals in the Coma and
Abell 262
Clusters
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
modelling. 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.
NIC3 10874
Search for Extremely Faint z>7 Galaxy Population with
Cosmic Lenses
Deep UDF/NICMOS observations find a significant decrease
in the number
of galaxy candidates between redshift z=6 and 7, but the
sample at z>7
is too small to draw conclusions. From our observations of
15 clusters
we have found a number of bright z-dropouts, aided by the
lensing
amplification. We propose deep NICMOS observations of the
best cases of
cluster centers where a rare combination of a significant
lensing effect
and the richness in z-band dropouts in background may
dramatically
increase the discovery rate. The NICMOS images will reach
an
unprecendented depth of AB~27.8, or AB~30 in nonlensed
intrinsic
magnitude, and may find many faint {~0.05L*} galaxies at
z=7-10, at a
level that the UDF reaches for z~6 objects. We produce
precision mass
distribution maps from weak-lensing models, which enable
us to derive
the candidates' intrinsic magnitudes and their luminosity
function. The
knowledge of such faint galaxy population at z>7 will
facilitate the
models of the IGM reionization and future JWST planning.
WFPC2 10818
Very Young Globular Clusters in M31 ?
We propose to use HST's unique high spatial resolution
imaging
capabilities to conclusively confirm or refute the
presence of alleged
very young globular clusters in M31. Such young globular
clusters with
ages < 3 Gyr are not present in our galaxy, and, if real,
would lead to
a striking difference in the age distribution of the GCs
between M31 and
the
in M31 is confirmed through our proposed ACS imaging {now
WFPC2 imaging}
with HST, this would suggest major differences in the
history of
assembly of the two galaxies, with probable substantial
late accretion
into M31 which did not occur in our own galaxy.
ACS/SBC 10810
The Gas Dissipation Timescale: Constraining Models of
Planet Formation
We propose to constrain planet-formation models by
searching for
molecular hydrogen emission around young {10-50 Myr}
solar-type stars
that have evidence for evolved dust disks. Planet
formation models show
that the presence of gas in disks is crucial to the
formation of BOTH
giant and terrestrial planets, influences dust dynamics,
and through
tidal interactions with giant planets leads to orbital
migration.
However, there is a lack of systematic information on the
presence and
lifetime of gas residing at planet-forming radii. We will
use a newly
identified broad continuum emission feature of molecular
hydrogen at
1600 Angstrom to search for residual gas within an orbital
radius of
5-10 AU around young stars that have evolved beyond the
optically thick
T Tauri phase. These observations will enable the most
sensitive probe
to date of remant gas in circumstellar disks, detecting
surfaces
densites of ~0.0001 g/cm^2, or less than 10^-5 of the
theoretical
"mininum mass" solar nebula from which our solar
system is thought to
have formed. Our observations are designed to be
synergistic with
ongoing searches for gas emission that is being performed
using the
Spitzer Space Telescope in that the proposed HST
observations are ~100
times more sensitive and will have 50 times higher angular
resolution.
These combined studies will provide the most comprehensive
view of
residual gas in proto- planetary disks and can set
important constraints
on models of planet formation.
ACS/HRC 10806
Accretion in the closest binary systems known
Recently, three variable stars have been identified as
likely accreting
binary systems with ultra- short orbital periods. Optical
and X-ray
observations have revealed periodicities of 5-10 minutes,
making them
the closest binaries known as well as strong sources of
gravitational
wave emission. Such short-period accreting binaries form
the cornerstone
to our understanding of binary formation and evolution, in
particular of
the large double white dwarf population in our galaxy, a
candidate
progenitor population for
first UV spectroscopy of these objects using the ACS
prisms in order to
{i} determine the temperature of the primary and the
composition of
their donor stars, {ii} correlate the UV variability with
other
wavebands and determine if the periods are indeed orbital.
These UV
observations are essential in order to unequivocally
determine whether
these are indeed the most compact binaries known.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
#10892 OBAD Failed Quaternion (ESB 1903) & OBAD Too
few stars
(ESB 1901).
At 194/19:00:38 "OBAD Failed Quaternion".
At 19:01:37
equation F2SOB flagged indicating entering
Stuck-on-Bottom. At 19:05:42
F2SOB returned back in bounds due to start of OBAD #2. At
19:08:26
received error "OBAD Too few stars". At 19:09:31
equation F2SOB flagged
indicating Stuck-on-Bottom. Unable to perform OBAD table
dumps as
forward ended at 19:01:01. OBAD #1: V1 673.57, V2
-1769.09, V3 -336.61,
RSS 1922.68 OBAD #2: Same numbers as above OBAD MAP: V1
593.88, V2
-1714.43, V3 -423.05, RSS 1863.05 GSAcq scheduled at
19:10:43 was not
attempted.
#10893 GSAcq (1,2,2) failed due to Search Radius Limit
Exceeded on FGS
1.
At AOS (195/01:05:57) GSAcq (1,2,2) scheduled from
195/00:00:14-00:07:34
failed due to search radius limit exceeded on FGS 1. OBAD
data unavailable
due to LOS. OBAD MAP RSS: 49.95
#10894 GSacq(2,1,2) failed, Search Radius Limit exceeded
on FGS 2.
Upon acquisition of signal at 195/19:25:25 vehicle was in
RGA control with
FGS2 Search Radius Limit and Stop flags set. GSacq(2,1,2)
scheduled at
19:11:56 failed with search radius limit exceeded on FGS
2.
Post-acquisition OBAD/MAP at 19:20:00 had RSS error of
20.16 arcseconds.
OBADs prior to GSACQ are not available. REACQ(2,1,2) at
20:44:12 was
successful.
#10895 GSaqc(1,2,2) failed to RGA control.
The GSacq(1,2,2) scheduled at 195/22:21:07 failed during
LOS due to search
radius limit exceeded on FGS 1. The map at 22:28:27 showed
errors of
V1=o.33, V2=-3.53, V3=61.25, and RSS= 61.35.
#10896 OBAD Failed Identification (ESB 1902).
OBAD1 scheduled at 195/23:47:00 failed during LOS. OBAD2
and the
GSacq was successful.
#10897 REacq(1,3,1) failed, Search Radius Limit exceeded
on FGS 2.
REacq(1,3,1) at 196/11:07:23 failed at 11:13:04 with
search radius limit
exceeded on FGS 1. OBADs prior to REacq at 11:03:03 had
RSS error of
59.84 arcseconds, Post-acquisition OBAD/MAP at 11:15:27
had RSS error of
62.24 arcseconds.
COMPLETED OPS REQUEST:
#17597-9 FHST Stuck-on-Bottom Macro Execution @ 196/0136z
& 196/0322z
SCHEDULED SUCCESSFUL
FGS GSacq 25
21
FGS REacq
18
17
OBAD with
Maneuver
86
83
COMPLETED OPS NOTES: (None)
SIGNIFICANT EVENTS: (None)