Notice: For the foreseeable future, the daily reports may
contain
apparent discrepancies between some proposal descriptions
and the listed
instrument usage. This is due to the conversion of
previously approved
ACS WFC or HRC observations into WFPC2, or NICMOS
observations
subsequent to the loss of ACS CCD science capability in
late January.
HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4382
PERIOD COVERED: UT June 12, 2007 (DOY 163)
OBSERVATIONS SCHEDULED
WFPC2 10880
The host galaxies of QSO2s: AGN feeding and evolution at
high
luminosities
Now that the presence of supermassive black holes in the
nuclei of
galaxies is a well established fact, other questions
related to the AGN
phenomena still have to be answered. Problems of
particular interest are
how the AGN gets fed, how the black hole evolves and how
the evolution
of the black hole is related to the evolution of the
galaxy bulge. Here
we propose to address some of these issues using ACS/WFC +
F775W
snapshot images of 73 QSO2s with redshifts in the range
0.3<z<0.4. These
observations will be combined with similar archival data
of QSO1s and
ground based data of Seyfert and normal galaxies. First,
we will
intestigate whether interactions are the most important
feeding
mechanism in high luminosity AGNs. This will be done in a
quantitative
way, comparing the asymmetry indices of QSO2 hosts with
those of lower
luminosity AGNs and normal galaxies. Second, we will do a
detailed study
of the morphology of the host galaxies of both QSO types,
to determine
if they are similar, or if there is an evolutionary trend
from QSO2s to
QSO1s. The results from this project will represent an
important step in
the understanding of AGN evolution, and may also introduce
a substantial
modification to the Unified Model.
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 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.
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.
WFPC2 11081
RR Lyrae stars in M31 Globular Clusters: How did the M31
Spiral Galaxy
Form?
The pulsation properties of the RR Lyrae stars in the
globular clusters
of the Andromeda galaxy {M31} have the potential to
provide essential
insight on the first epoch of the galaxy formation and to
trace the
merging episodes that led to the assembly of M31. Their
mean periods
along with the cluster metallicities can provide an
independent estimate
of the M31 cluster ages and, in turn, of the time scale of
the M31 halo
formation, by comparison with their Milky Way
counterparts. We will
observe RR Lyrae stars in 6 appropriately selected
globular clusters of
M31 using WFPC2 to derive periods, light curves, and
physical parameters
of these eyewitnesses of the first epochs of the M31
formation.
WFPC2 11083
The Structure, Formation and Evolution of Galactic Cores
and Nuclei
A surprising result has emerged from the ACS Virgo Cluster
Survey
{ACSVCS}, a program to obtain ACS/WFC gz imaging for a
large, unbiased
sample of 100 early-type galaxies in the Virgo Cluster. On
subarcsecond
scales {i.e., <0.1"-1"}, the HST brightness
profiles vary systematically
from the brightest giants {which have nearly constant
surface brightness
cores} to the faintest dwarfs {which have compact stellar
nuclei}.
Remarkably, the fraction of galaxy mass contributed by the
nuclei in the
faint galaxies is identical to that contributed by
supermassive black
holes in the bright galaxies {0.2%}. These findings
strongly suggest
that a single mechanism is responsible for both types of
Central Massive
Object: most likely internally or externally modulated gas
inflows that
feed central black holes or lead to the formation of
"nuclear star
clusters". Understanding the history of gas
accretion, star formation
and chemical enrichment on subarcsecond scales has thus
emerged as the
single most pressing question in the study of nearby
galactic nuclei,
either active or quiescent. We propose an ambitious HST
program {199
orbits} that constitutes the next, obvious step forward:
high-resolution, ultraviolet {WFPC2/F255W} and infrared
{NIC1/F160W}
imaging for the complete ACSVCS sample. By capitalizing on
HST's unique
ability to provide high-resolution images with a sharp and
stable PSF at
UV and IR wavelengths, we will leverage the existing optical
HST data to
obtain the most complete picture currently possible for
the history of
star formation and chemical enrichment on these small
scales. Equally
important, this program will lead to a significant
improvement in the
measured structural parameters and density distributions
for the stellar
nuclei and the underlying galaxies, and provide a
sensitive measure of
"frosting" by young stars in the galaxy cores.
By virtue of its superb
image quality and stable PSF, NICMOS is the sole
instrument capable of
the IR observations proposed here. In the case of the
WFPC2
observations, high-resolution UV imaging {< 0.1"}
is a capability unique
to HST, yet one that could be lost at any any time.
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
04
04
FGS REacq
11
11
OBAD with Maneuver
29
29
SIGNIFICANT EVENTS: (None)