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 # 4323
PERIOD COVERED: UT March 20, 2007 (DOY 079)
OBSERVATIONS SCHEDULED
WFPC2 10563
Accurate dark-matter mass profiles in 3 elliptical
galaxies as a test of
CDM
A critical test of the successful Lambda-CDM picture for
structure
formation is the measurement of the power law exponent,
gamma, of the
centre of dark matter density profiles, predicted to lie
in the range
1.0-1.5. Measurements of gamma derived from rotation
curves of LSB
galaxies appear to contradict CDM, but rely on assumptions
that are
difficult to verify {e.g. axisymmetry}. We have recently
demonstrated,
using our new `semi- linear' inversion method, how strong
gravitational
lensing by galaxies can provide a clean and accurate
measurement of
gamma, free of such ambiguities. HST images of lensed
non-AGN galaxies
provide hundreds of resolution elements, each a constraint
on the mass
profile. Such lenses are exceedingly rare, but we have
recently
discovered new systems. We propose deep ACS-HRC
observations of 3
systems to measure gamma in each, accurate to 0.15 {95%
confidence} and
to obtain an indication of its variation between galaxies.
To establish
the required number of orbits we have undertaken an
end-to-end
simulation of the problem, creating and analysing
synthetic ACS images.
Additionally the semi-linear method simultaneously
reconstructs the
pixelised source surface brightness distribution. Our
simulations
demonstrate that the fine sampling and small pixel
scattering of the
HRC, resolves the morphology of the sources with exquisite
detail.
WFPC2 10833
Host Galaxies of Reverberation Mapped AGNs
We propose to obtain unsaturated high-resolution images of
17
reverberation-mapped active galactic nuclei in order to
remove the
point-like nuclear light from each image, thus yielding a
"nucleus-free"
image of the host galaxy. This will allow investigation of
host galaxy
properties: our particular interest is determination of
the host-galaxy
starlight contribution to the reverberation-mapping
observations. This
is necessary {1} for accurate determination of the
relationship between
the AGN nuclear continuum flux and the size of the broad
Balmer-line
emitting regions of AGNs, which is important in estimating
black hole
masses for large samples of QSOs, and {2} for accurate
determination of
the bolometric luminosity of the AGN proper. Through
observations in
Cycles 12 and 14, we have obtained or will obtain images
of 18 of the 35
objects in the reverberation-mapping compilation of
Peterson et al.
{2004}. These observations revealed that the host-galaxy
contribution,
even in the higher-luminosity AGNs, is higher than
expected and that all
of the reverberation- mapped AGNs will have to be
observed, not just the
lower-luminosity sources; each source is different, and
each source is
important. Therefore we request time to observe the 17
remaining
reverberation-mapped AGNs.
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.
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/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.
NIC2 10802
SHOES-Supernovae, HO, for the Equation of State of Dark
energy
The present uncertainty in the value of the Hubble
constant {resulting
in an uncertainty in Omega_M} and the paucity of
redshifts exceeding 1 are now the leading obstacles to
determining the
nature of dark energy. We propose a single, integrated set
of
observations for Cycle 15 that will provide a 40%
improvement in
constraints on dark energy. This program will observe
known Cepheids in
six reliable hosts of
uncertainty in H_0 by a factor of two because of the
smaller dispersion
along the instability strip, the diminished extinction,
and the weaker
metallicity dependence in the infrared. In parallel with
ACS, at the
same time the NICMOS observations are underway, we will
discover and
follow a sample of
measurements, along with prior constraints from WMAP, will
provide a
great improvement in HST's ability to distinguish between
a static,
cosmological constant and dynamical dark energy. The
Hubble Space
Telescope is the only instrument in the world that can
make these IR
measurements of Cepheids beyond the Local Group, and it is
the only
telescope in the world that can be used to find and follow
supernovae at
z > 1. Our program exploits both of these unique
capabilities of HST to
learn more about one of the greatest mysteries in science.
NIC3 11080
Exploring the Scaling Laws of Star Formation
As a variety of surveys of the local and distant Universe
are
approaching a full census of galaxy populations, our
attention needs to
turn towards understanding and quantifying the physical mechanisms
that
trigger and regulate the large-scale star formation rates
{SFRs} in
galaxies.
WFPC2 10890
Morphologies of the Most Extreme High-Redshift
Mid-IR-Luminous Galaxies
The formative phase of the most massive galaxies may be
extremely
luminous, characterized by intense star- and
AGN-formation. Till now,
few such galaxies have been unambiguously identified at
high redshift,
restricting us to the study of low-redshift ultraluminous
infrared
galaxies as possible analogs. We have recently discovered
a sample of
objects which may indeed represent this early phase in
galaxy formation,
and are undertaking an extensive multiwavelength study of
this
population. These objects are bright at mid-IR wavelengths
{F[24um]>0.8mJy}, but deep ground based imaging
suggests extremely faint
{and in some cases extended} optical counterparts
{R~24-27}. Deep K-band
images show barely resolved galaxies. Mid-infrared
spectroscopy with
Spitzer/IRS reveals that they have redshifts z ~ 2-2.5,
suggesting
bolometric luminosities ~10^{13-14}Lsun! We propose to
obtain deep ACS
F814W and NIC2 F160W images of these sources and their
environs in order
to determine kpc-scale morphologies and surface photometry
for these
galaxies. The proposed observations will help us determine
whether these
extreme objects are merging systems, massive obscured
starbursts {with
obscuration on kpc scales!} or very reddened {locally
obscured} AGN
hosted by intrinsically low-luminosity galaxies.
WFPC2 11085
Europa in Eclipse: Tenuous Atmosphere, Electromagnetic
Activity and
Surface Luminescence HST Proposal 11085
We propose to image Europa during its orbital eclipse by
Jupiter. This
will form the basis of an investigation into the nature of
the tenuous
atmosphere, electromagnetic environment and surface
material of Europa.
We will compare the FUV oxygen line at 1356A to the
optical line at
6300A and seek optical auroral hydrogen emission in
Halpha. With broad
continuum filters, we will search for optical emissions
from other
atmospheric constituents and for fluorescence of the
surface material,
arising from the very high level of incident energetic
particle
radiation. The high spatial resolution of ACS will allow
us to fully
resolve scales of interest and allow us to distinguish easily
the
different terrains on Europa's surface. In particular we
wish to compare
luminesence in regions dominated by ice to those of
potentially organic
red material.
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
09
09
FGS REacq
06
06
OBAD with Maneuver
29
29
SIGNIFICANT EVENTS: (None)