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 # 4473
PERIOD
COVERED: UT October 22, 2007 (DOY 295)
OBSERVATIONS
SCHEDULED
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.
WFPC2
11024
WFPC2
CYCLE 15 INTERNAL MONITOR
This
calibration proposal is the Cycle 15 routine internal monitor for
WFPC2,
to be run weekly to monitor the health of the cameras. A variety
of
internal exposures are obtained in order to provide a monitor of the
integrity
of the CCD camera electronics in both bays {both gain 7 and
gain
15 -- to test stability of gains and bias levels}, a test for
quantum
efficiency in the CCDs, and a monitor for possible buildup of
contaminants
on the CCD windows. These also provide raw data for
generating
annual super-bias reference files for the calibration
pipeline.
FGS
11211
An
Astrometric Calibration of Population II Distance Indicators
In
2002 HST produced a highly precise parallax for RR Lyrae. That
measurement
resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a
useful
result, judged by the over ten refereed citations each year
since.
It is, however, unsatisfactory to have the direct,
parallax-based,
distance scale of Population II variables based on a
single
star. We propose, therefore, to obtain the parallaxes of four
additional
RR Lyrae stars and two Population II Cepheids, or
stars.
The Population II Cepheids lie with the RR Lyrae stars on a
common
K-band Period-Luminosity relation. Using these parallaxes to
inform
that relationship, we anticipate a zero-point error of 0.04
magnitude.
This result should greatly strengthen confidence in the
Population
II distance scale and increase our understanding of RR Lyrae
star
and Pop II Cepheid astrophysics.
NIC2
11197
Sweeping
Away the Dust: Reliable Dark Energy with an Infrared Hubble
Diagram
We
propose building a high-z Hubble Diagram using type Ia supernovae
observed
in the infrared rest-frame J-band. The infrared has a number of
exceptional
properties. The effect of dust extinction is minimal,
reducing
a major systematic that may be biasing dark energy
measurements.
Also, recent work indicates that type Ia supernovae are
true
standard candles in the infrared meaning that our Hubble diagram
will
be resistant to possible evolution in the Phillip's relation over
cosmic
time. High signal-to-noise measurements of 16 type Ia events at
z~0.4
will be compared with an independent optical Hubble diagram from
the
ESSENCE project to test for a shift in the derived dark energy
equation
of state due to a systematic bias. In Cycle 15 we obtained
NICMOS
photometry of 8 ESSENCE supernovae and are awaiting template
observations
to place them on the IR Hubble diagram. Here we request
another
8 supernovae be studied in the final season of the ESSENCE
search.
Because of the bright sky background, H-band photometry of z~0.4
supernovae
is not feasible from the ground. Only the superb image
quality
and dark infrared sky seen by HST makes this test possible. This
experiment
may also lead to a better, more reliable way of mapping the
expansion
history of the universe with the Joint Dark Energy Mission.
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
11070
WFPC2
CYCLE 15 Standard Darks - part II
This
dark calibration program obtains dark frames every week in order to
provide
data for the ongoing calibration of the CCD dark current rate,
and
to monitor and characterize the evolution of hot pixels. Over an
extended
period these data will also provide a monitor of radiation
damage
to the CCDs.
WFPC2
11130
AGNs
with Intermediate-mass Black Holes: Testing the Black Hole-Bulge
Paradigm,
Part II
The
recent progress in the study of central black holes in galactic
nuclei
has led to a general consensus that supermassive {10^6-10^9 solar
mass}
black holes are closely connected with the formation and
evolutionary
history of large galaxies, especially their bulge
component.
Two outstanding issues, however, remain unresolved. Can
central
black holes form in the absence of a bulge? And does the mass
function
of central black holes extend below 10^6 solar masses?
Intermediate-mass
black holes {<10^6 solar masses}, if they exist, may
offer
important clues to the nature of the seeds of supermassive black
holes.
Using the SDSS, our group has successfully uncovered a new
population
of AGNs with intermediate-mass black holes that reside in
low-luminosity
galaxies. However, very little is known about the
detailed
morphologies or structural parameters of the host galaxies
themselves,
including the crucial question of whether they have bulges
or
not. Surprisingly, the majority of the targets of our Cycle 14 pilot
program
have structural properties similar to dwarf elliptical galaxies.
The
statistics from this initial study, however, are really too sparse
to
reach definitive conclusions on this important new class of black
holes.
We wish to extend this study to a larger sample, by using the
Snapshot
mode to obtain WFPC2 F814W images from a parent sample of 175
AGNs
with intermediate-mass black holes selected from our final SDSS
search.
We are particularly keen to determine whether the hosts contain
bulges,
and if so, how the fundamental plane properties of the host
depend
on the mass of their central black holes. We will also
investigate
the environment of this unique class of AGNs.
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
11194
Beyond
the Bullet: Direct Detection of Dark Matter in Merging Galaxy
Clusters
Our
comparison of the distribution of baryons {stars and gas} and mass
{from
weak lensing} in the "Bullet" Cluster has recently yielded
concrete
evidence for dark matter independent of basic assumptions
regarding
the nature of the gravitational force. The one incomplete
aspect
of the argument relates to potential, although highly unlikely,
coincidences
{special alignments along the line of sight, and/or
fortuitous
canceling in non- standard gravitational models} that can
always
be invoked against results derived from the study of one object.
Therefore,
we propose to complete this line of investigations by
increasing
the size of our sample with observations of an additional
cluster.
Here we propose to obtain HST WFPC2 imaging mosaics around the
cores
of the cluster to detect at high significance if the weak
gravitational
lensing mass peaks are routinely displaced from the X-ray
plasma
clouds and aligned with the galaxy concentrations in interacting
clusters.
With a relatively modest allocation of time, we seek to
complete
a significant step toward the eventual resolution of the dark
matter
question.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11034
- Guide Star Acquisition Failure
GSacq1,3,3
at 296/00:00:00 failed due to stop flag on FGS 1. The failure
occurred
during LOS. Observations affected include WFPC 70,71,72,73.
Two
OBADs before the GSacq were successful with errors of:
OC1,3: V1 112.61; V2 -463.47; V3 148.48; RSS 499.53
OC1,2 : V1
3.73; V2 6.40; V3 -5.80 ; RSS 9.41
The map after the failed guide star acq showed errors of:
V1 -3.25; V2 -7>11; V3 11.57; RSS 13.96
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
10
09
FGS
REacq
04
04
OBAD
with Maneuver
28
28
SIGNIFICANT
EVENTS: (None)