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
# 4334
PERIOD COVERED: UT April 05, 2007
(DOY 094)
OBSERVATIONS SCHEDULED
ACS/SBC 11050
ACS UV contamination monitor
The observations consist of
imaging and spectroscopy with SBC of the
cluster NGC 6681 in order to
monitor the temporal evolution of the UV
sensitivity of the SBC.
WFPC2 10798
Dark Halos and Substructure from
Arcs & Einstein Rings
The surface brightness
distribution of extended gravitationally lensed
arcs and Einstein rings contains
super-resolved information about the
lensed object, and, more
excitingly, about the smooth and clumpy mass
distribution of the lens galaxies.
The source and lens information can
non-parametrically be separated,
resulting in a direct "gravitational
image" of the inner
mass-distribution of cosmologically-distant
galaxies
{Koopmans 2005; Koopmans et al.
2006 [astro-ph/0601628]}. With this goal
in mind, we propose deep HST
ACS-F555W/F814W and NICMOS-F160W WFC
imaging of 20 new
gravitational-lens systems with spatially resolved
lensed sources, of the 35 new lens
systems discovered by the Sloan Lens
ACS Survey {Bolton et al. 2005} so
far, 15 of which are being imaged in
Cycle-14. Each system has been
selected from the SDSS and confirmed in
two time- efficient HST-ACS
snapshot programs {cycle 13&14}.
High-fidelity multi-color HST
images are required {not delivered by the
420s snapshots} to isolate these
lensed images {properly cleaned,
dithered and extinction-corrected}
from the lens galaxy surface
brightness distribution, and apply
our "gravitational maging" technique.
Our sample of 35 early-type lens
galaxies to date is by far the largest,
still growing, and most uniformly
selected. This minimizes selection
biases and small-number
statistics, compared to smaller, often
serendipitously discovered,
samples. Moreover, using the WFC provides
information on the field around
the lens, higher S/N and a better
understood PSF, compared with the
HRC, and one retains high spatial
resolution through drizzling. The
sample of galaxy mass distributions -
determined through this method
from the arcs and Einstein ring HST
images - will be studied to: {i}
measure the smooth mass distribution of
the lens galaxies {dark and
luminous mass are separated using the HST
images and the stellar M/L values
derived from a joint stellar-dynamical
analysis of each system}; {ii}
quantify statistically and individually
the incidence of mass-substructure
{with or without obvious luminous
counter- parts such as dwarf
galaxies}. Since dark-matter substructure
could be more prevalent at higher
redshift, both results provide a
direct test of this prediction of
the CDM hierarchical
structure-formation model.
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.
WFPC2 10886
The Sloan Lens ACS Survey: Towards
100 New Strong Lenses
As a continuation of the highly
successful Sloan Lens ACS {SLACS} Survey
for new strong gravitational
lenses, we propose one orbit of ACS-WFC
F814W imaging for each of 50
high-probability strong galaxy-galaxy lens
candidates. These observations
will confirm new lens systems and permit
immediate and accurate photometry,
shape measurement, and mass modeling
of the lens galaxies. The lenses
delivered by the SLACS Survey all show
extended source structure,
furnishing more constraints on the projected
lens potential than lensed-quasar
image positions. In addition, SLACS
lenses have lens galaxies that are
much brighter than their lensed
sources, facilitating detailed
photometric and dynamical observation of
the former. When confirmed lenses
from this proposal are combined with
lenses discovered by SLACS in
Cycles 13 and 14, we expect the final
SLACS lens sample to number
80--100: an approximate doubling of the
number of known galaxy-scale
strong gravitational lenses and an
order-of-magnitude increase in the
number of optical Einstein rings. By
virtue of its homogeneous
selection and sheer size, the SLACS sample
will allow an unprecedented
exploration of the mass structure of the
early-type galaxy population as a
function of all other observable
quantities. This new sample will
be a valuable resource to the
astronomical community by enabling
qualitatively new strong lensing
science, and as such we will waive
all but a short {3-month} proprietary
period on the observations.
NIC1 10859
Precise Measurements of Sgr A*
Flare Activity
Correlated X-ray and near-IR flare
emission from Sgr A*, the closest
supermassive black hole, contains
information about the hydrodynamics,
energetics, and accretion behavior
of matter within the innermost ten
Schwarzschild radii of the hole.
We propose HST/NICMOS observations of
near-IR flares, in conjunction
with already approved obsrevations using
XMM-Newton {214 ksec} and CSO {3
nights}, which can make the precise,
new measurements necessary to
understand the radiation mechanism and low
luminosity of Sgr A*. HST/NICMOS
is required due to its very low and
stable background, and its stable,
tightly focused PSF, which allow
accurate measurement of fainter
flares than can be observed using
groundbased adaptive optics
systems. We will measure the spectral index
distribution, the time-averaged
flux and duration of flares, and the
statistics of flare activity, and
will confirm previously reported
quasi-periodic variability. These
measurements will have far-reaching
implications for testing the
inverse Compton scattering {ICS}
and
synchrotron models of
low-luminosity flares, for understanding the
process of accretion onto and
outflow from supermassive black holes, and
for constraining the acceleration
mechanism of flares and the inferred
black hole spin. This knowledge,
in turn, will help us understand more
generally low-luminosity AGN and
X-ray binaries in a very low/quiescent
accretion state.
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA calibration - CR
Persistence Part 6
A new proceedure proposed to
alleviate the CR-persistence problem of
NICMOS. Dark frames will be
obtained immediately upon exiting the SAA
contour 23, and everytime 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.
WFPC2 11022
WFPC2 Cycle 15 Decontaminations
and Associated Observations
This proposal is for the WFPC2
decons. Also included are instrument
monitors tied to decons:
photometric stability check, focus monitor,
pre- and post-decon internals
{bias, intflats, kspots, & darks}, UV
throughput check, VISFLAT sweep,
and internal UV flat check.
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.
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
10
10
FGS
REacq
05
05
OBAD with Maneuver
30
30
SIGNIFICANT EVENTS:
(None)