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 # 4319
PERIOD COVERED: UT March 14, 2007 (DOY 073)
OBSERVATIONS SCHEDULED
FGS 10801
Direct Determination of Kuiper Belt Object Diameters with
HST
When it comes to fundamental properties of an astronomical
object, it is
difficult to think of a more fundamental physical property
than its
size. Because of their distance, objects in the Kuiper
Belt are
generally too small for their disks to be resolved. The
heterogeneous
albedo and color of the Kuiper Belt population makes size
estimates from
observed absolute magnitude highly uncertain. And the
long-awaited data
from the Spitzer Space Telescope suffers from our
ignorance of crucial
macro- and micro-physical properties such as spin period,
pole
orientation, surface roughness, and thermal inertia. We
propose to add a
new dimension to the measurement of KBO diameters by employing
two
techniques that will directly measure the diameters of
three large KBOs.
We expect to obtain diameter measurements with
uncertainties of 10% or
better and utilize these to validate and cross calibrate
the growing web
of diameter measurements for KBOs.
NIC2 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.
FGS 10989
Astrometric Masses of Extrasolar Planets and Brown Dwarfs
We propose observations with HST/FGS to estimate the
astrometric
elements {perturbation orbit semi-major axis and
inclination} of
extra-solar planets orbiting six stars. These companions
were originally
detected by radial velocity techniques. We have
demonstrated that FGS
astrometry of even a short segment of reflex motion, when
combined with
extensive radial velocity information, can yield useful
inclination
information {McArthur et al. 2004}, allowing us to
determine companion
masses. Extrasolar planet masses assist in two ongoing
research
frontiers. First, they provide useful boundary conditions
for models of
planetary formation and evolution of planetary systems.
Second, knowing
that a star in fact has a plantary mass companion,
increases the value
of that system to future extrasolar planet observation missions
such as
SIM PlanetQuest, TPF, and GAIA.
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 11084
Probing the Least Luminous Galaxies in the Local Universe
We propose to obtain deep color-magnitude data of eight
new Local Group
galaxies which we recently discovered: Andromeda XI,
Andromeda XII, and
Andromeda XIII {satellites of M31}; Canes Venatici I,
Canes Venatici II,
Hercules, and Leo IV {satellites of the Milky Way}; and
Leo T, a new
"free-floating" Local Group dwarf spheroidal
with evidence for recent
star formation and associated H I gas. These represent the
least
luminous galaxies known at *any* redshift, and are the
only accessible
laboratories for studying this extreme regime of galaxy
formation. With
deep WFPC-2 F606W and F814W pointings at their centers, we
will
determine whether these objects contain single or multiple
age stellar
populations, as well as whether these objects display a
range of
metallicities.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
10739 - GSAcq (1,2,1) failed due to QSTOP Flag on FGS
GSAcq (1,2,1) at 074/02:12:05-02:19:22 failed due to QSTOP & QF1STOPF
flaggs on FGS 1. Received no 486 ESB messages.
OBAD #1 RSS: 3424.76
OBAD #2 RSS: 16.98
OBAD MAP RSS: 2.37
10740 - ACS 779 Fold Mechanism Move was Blocked
At
074/02:20:24 Received Status Buffer Message ACS 779 (x2) (Fold
Mechanism Move Was Blocked) #1 P=0, T= 30057, #2 P=0, T=35017. This was
the result of the failed GSAcq at 02:14:58 so the TDF was down when the
fold mechanism move to the SBC position was commanded. The move is
blocked and SBC MAMA HV will remain on. The MAMA HV staying on is a new
feature for ACS FSW CS4.01
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
09
08
FGS
REacq
06
06
OBAD with Maneuver
30
30
SIGNIFICANT EVENTS: (None)