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 #
4399
PERIOD COVERED: UT July 06, 07, 08, 2007 (DOY 187,188,189)
OBSERVATIONS SCHEDULED
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.
FGS 11294
The orbit of the most massive known astrometric
binary
We have recently used FGS and HRC observations to {a}
resolve HD 93129A
into two components with very
similar optical/UV colors and a magnitude
difference of 1.3 and to {b} detect their
relative orbital motion over a
span of 8 years. HD 93129Aa is the
prototype O2 If* star, with an
evolutionary mass near 100 M_Sun, while Ab is likely to be a
very early
O main-sequence star with a similar or only slightly
smaller mass. Our
HST astrometric measurements
yield a total mass above 100 M_Sun, thus
confirming the extremely high mass of the
binary, and indicate that the
system appears to be approaching periastron. We request new FGS
observations to {a} calculate the mass ratio
of the system by measuring
the orbit of each of the components
with respect to the nearby stars,
{b} obtain the periastron epoch, and {c} start measuring the orbit in
order to produce an estimate of the
total mass. These measurements are
crucial to shed light on the value of
the stellar upper mass limit.
WFPC2 11289
SL2S: The Strong Lensing Legacy
Survey
Recent systematic surveys of strong galaxy-galaxy lenses
{CLASS, SLACS,
GOODS, etc.} are
producing spectacular results for galaxy masses roughly
below a transition mass M~10^13 Mo.
The observed lens properties and
their evolution up to z~0.2,
consistent with numerical simulations, can
be described by isothermal
elliptical potentials. In contrast, modeling
of giant arcs in X-ray luminous
clusters {halo masses M >~10^13 Mo}
favors NFW mass profiles, suggesting
that dark matter halos are not
significantly affected by baryon cooling.
Until recently, lensing
surveys were neither deep nor extended
enough to probe the intermediate
mass density regime, which is
fundamental for understanding the assembly
of structures. The CFHT Legacy
Survey now covers 125 square degrees, and
thus offers a large reservoir of
strong lenses probing a large range of
mass densities up to z~1. We have
extracted a list of 150 strong lenses
using the most recent CFHTLS data
release via automated procedures.
Following our first SNAPSHOT proposal in cycle 15, we
propose to
continue the Hubble follow-up targeting
a larger list of 130 lensing
candidates. These are intermediate mass
range candidates {between
galaxies and clusters} that are selected
in the redshift range of 0.2-1
with no a priori X-ray selection.
The HST resolution is necessary for
confirming the lensing
candidates, accurate modeling of the lenses, and
probing the total mass concentration in
galaxy groups up to z~1 with the
largest unbiased sample available to
date.
WFPC2 11229
SEEDS: The Search for Evolution of Emission from Dust in
Supernovae with
HST and
The role that massive stars play in the dust content of
the Universe is
extremely uncertain. It has long been
hypothesized that dust can
condense within the ejecta
of supernovae {SNe}, however there is a
frustrating discrepancy between the amounts
of dust found in the early
Universe, or predicted by nucleation theory, and inferred
from SN
observations. Our SEEDS collaboration has
been carefully revisiting the
observational case for dust formation by
core-collapse SNe, in order to
quantify their role as dust contributors
in the early Universe. As dust
condenses in expanding SN ejecta, it will increase in optical depth,
producing three simultaneously observable
phenomena: {1} increasing
optical extinction; {2} infrared {IR}
excesses; and {3} asymmetric
blue-shifted emission lines. Our SEEDS
collaboration recently reported
all three phenomena occuring in SN2003gd, demonstrating the success of
our observing strategy, and
permitting us to derive a dust mass of up to
0.02 solar masses created in the SN. To advance our
understanding of the
origin and evolution of the
interstellar dust in galaxies, we propose to
use HST's
WFPC2 and NICMOS instruments plus Spitzer's photometric
instruments to monitor ten recent core-
collapse SNe for dust formation
and, as a bonus, detect light
echoes that can affect the dust mass
estimates. These space-borne observations
will be supplemented by
ground- based spectroscopic monitoring
of their optical emission line
profiles. These observations would
continue our 2-year HST and Spitzer
monitoring of this phenomena in order to
address two key questions: Do
all SNe
produce dust? and How much dust do they produce? As
all the SN
are witin
15 Mpc, each SN stands an excellent chance of
detection with
HST and Spitzer and of resolving potential light echoes.
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.
FGS 11210
The Architecture of Exoplanetary
Systems
Are all planetary systems coplanar? Concordance cosmogony
makes that
prediction. It is, however, a prediction
of extrasolar planetary system
architecture as yet untested by direct
observation for main sequence
stars other than the Sun. To provide
such a test, we propose to carry
out FGS astrometric
studies on four stars hosting seven companions. Our
understanding of the planet formation process
will grow as we match not
only system architecture, but formed
planet mass and true distance from
the primary with host star
characteristics for a wide variety of host
stars and exoplanet
masses. We propose that a series of FGS astrometric
observations with demonstrated 1 millisecond
of arc per- observation
precision can establish the degree of coplanarity and component true
masses for four extrasolar
systems: HD 202206 {brown dwarf+planet}; HD
128311 {planet+planet}, HD
160691 = mu Arae {planet+planet}, and HD
222404AB = gamma Cephei {planet+star}. In each case the companion is
identified as such by assuming that the
minimum mass is the actual mass.
For the last target, a known stellar binary system, the
companion orbit
is stable only if coplanar with
the AB binary orbit.
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 11175
UV Imaging to Determine the Location of Residual Star
Formation in
Galaxies Recently Arrived on the Red Sequence
We have indentified a sample of
low-redshift {z = 0.04 - 0.10} galaxies
that are candidates for recent
arrival on the red sequence. They have
red optical colors indicative of
old stellar populations, but blue
UV-optical colors that could indicate the presence of a
small quantity
of continuing or very recent star
formation. However, their spectra lack
the emission lines that
characterize star-forming galaxies. We propose
to use ACS/SBC to obtain high-
resolution imaging of the UV flux in
these galaxies, in order to determine
the spatial distribution of the
last episode of star formation.
WFPC2 imaging will provide B, V, and I
photometry to measure the main stellar
light distribution of the galaxy
for comparison with the UV imaging,
as well as to measure color
gradients and the distribution of
interstellar dust. This detailed
morphological information will allow us to
investigate the hypothesis
that these galaxies have recently
stopped forming stars and to compare
the observed distribution of the
last star formation with predictions
for several different mechanisms
that may quench star formation in
galaxies.
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 11113
Binaries in the Kuiper Belt:
Probes of Solar System Formation and
Evolution
The discovery of binaries in the Kuiper
Belt and related small body
populations is powering a revolutionary
step forward in the study of
this remote region. Three quarters
of the known binaries in the Kuiper
Belt have been discovered with HST, most
by our snapshot surveys. The
statistics derived from this work are
beginning to yield surprising and
unexpected results. We have found a strong
concentration of binaries
among low-inclination Classicals, a possible size cutoff to binaries
among the Centaurs, an apparent
preference for nearly equal mass
binaries, and a strong increase in the
number of binaries at small
separations. We propose to continue this
successful program in Cycle 16;
we expect to discover at least 13
new binary systems, targeted to
subgroups where these discoveries can
have the greatest impact.
NIC2 11101
The Relevance of Mergers for Fueling AGNs:
Answers from QSO Host
Galaxies
The majority of QSOs are known
to reside in centers of galaxies that
look like ellipticals.
Numerical simulations have shown that remnants of
galaxy mergers often closely resemble
elliptical galaxies. However, it
is still strongly debated whether
the majority of QSO host galaxies are
indeed the result of relatively recent
mergers or whether they are
completely analogous to inactive ellipticals to which nothing
interesting has happened recently. To
address this question, we recently
obtained deep HST ACS images for five
QSO host galaxies that were
classified morphologically as ellipticals {GO-10421}. This pilot study
revealed striking signs of tidal
interactions such as ripples, tidal
tails, and warped disks that were not
detected in previous studies. Our
observations show that at least some
"elliptical" QSO host galaxies are
the products of relatively recent
merger events rather than old galaxies
formed at high redshift.
However, the question remains whether the host
galaxies of classical QSOs are truly distinct from inactive ellipticals
and whether there is a connection
between the merger events we detect
and the current nuclear activity.
We must therefore place our results
into a larger statistical context.
We are currently conducting an HST
archival study of inactive elliptical
galaxies {AR-10941} to form a
control sample. We now propose to
obtain deep HST/WFPC2 images of 13
QSOs whose host
galaxies are classified as normal ellipticals. Comparing
the results for both samples will
help us determine whether classical
QSOs reside in normal elliptical
galaxies or not. Our recent pilot study
of five QSOs
indicates that we can expect exciting results and deep
insights into the host galaxy morphology
also for this larger sample of
QSOs. A statistically meaningful
sample will help us determine the true
fraction of QSO hosts that suffered
strong tidal interactions and thus,
whether a merger is indeed a
requirement to trigger nuclear activity in
the most luminous AGNs. In addition to our primary science observations
with WFPC2, we will obtain NICMOS3
parallel observations with the
overall goal to select and characterize
galaxy populations at high
redshifts. The imaging will be among the
deepest NICMOS images: These
NICMOS images are expected to go to a limit a little over
1 magnitude
brighter than HUDF-NICMOS data, but over
13 widely separated fields,
with a total area about 1.5 times
larger than HUDF-NICMOS. This
separation means that the survey will tend
to average out effects of
cosmic varience.
The NICMOS3 images will have sufficient resolution for
an initial characterization of
galaxy morphologies, which is currently
one of the most active and
promising areas in approaching the problem of
the formation of the first massive
galaxies. The depth and area coverage
of our proposed NICMOS
observations will also allow a careful study of
the mass function of galaxies at
these redshifts. This provides a large
and unbiased sample, selected in
terms of stellar mass and unaffected by
cosmic variance, to study the on-going
star formation activity as a
function of mass {i.e. integrated star
formation} at this very important
epoch.
NIC1 11063
NICMOS Focus Monitoring
This program is a version of the standard focus sweep used
since cycle
7. It has been modified to go deeper and uses more narrow
filters for
improved focus determination. For
Cycle14 a new source has been added in
order to accomodate
2-gyro mode: the open cluster NGC1850. The old
target, the open cluster NGC3603, will
be used whenever available and
the new target used to fill the
periods when NGC3603 is not visible.
Steps: a} Use refined target field positions as determined
from cycle 7
calibrations b} Use MULTIACCUM sequences of
sufficient dynamic range to
account for defocus c} Do a 17- point
focus sweep, +/- 8mm about the PAM
mechanical zeropoint
for each cameras 1 and 2, in 1.0mm steps. d} Use
PAM X/Y tilt and OTA offset slew compensations refined
from previous
focus monitoring/optical alignment
activities
WFPC2 11028
WFPC2 Cycle 15 UV Earth Flats
Monitor flat field stability. This proposal obtains
sequences of earth
streak flats to improve the quality of
pipeline flat fields for the
WFPC2 UV filter set. These Earth flats will complement the
UV earth flat
data obtained during cycles 8-14.
WFPC2/ACS/HRC/WFPC 11020
Cycle 15 Focus Monitor
The focus of HST is measured primarily with ACS/HRC over
full CVZ orbits
to obtain accurate mean focus
values via a well sampled breathing curve.
Coma and astigmatism are also determined from the same
data in order to
further understand orbital effects on
image quality and optical
alignments. To monitor the stability of
ACS to WFPC2 relative focii,
we've carried over from previous
focus monitor programs parallel
observations taken with the two cameras at
suitable orientations of
previously observed targets, and
interspersed them with the HRC CVZ
visits.
FGS 11019
Monitoring FGS1r's Interferometric
Response as a Function of Spectral
Color
This proosal uses FGS1r in
Transfer mode to observe standard single
stars of a variety of spectral types
to obtain point source
interferograms for the Transfer mode
calibration library. In specific
cases, the calibration star will also
be observed in POS mode multiple
times with the F583W and F5ND
elements to provide the data to verify the
stabiligy of the cross filter
calibration.
WFPC2 10837
Establishing the Nature of a Mysterious Evolved Star,
HD179821
We propose to reobserve the
spherical circumstellar shells of an evolved
star, HD 179821. The nature of this
object, whether it is an
intermediate-mass post-asymptotic giant branch
star or a massive
super-giant, has been debated over years.
The past investigations
scrutinized the properties of the object
and its circumstellar shells.
This enigmatic object possesses characteristics of a
post-AGB star and a
yellow hyper-giant, and there is no
evidence that unambiguously defines
the nature of this object. The circumstellar shell of HD 179821 was
imaged in the previous WFPC2
observations during cycle 6, and its
multiple concentric arcs extending out
to about 8 arcsec were revealed.
The purpose of the proposed HST observations is to obtain
the
second-epoch images of this source and
perform proper-motion
measurements of the shells in order to
directly determine the distance
to this object, thereby
establishing its incredibly elusive nature once
and for all. It has been nearly 10
years since the last observations.
Given the object's rather high expansion velocity of 34
km/s, the
expected angular expansion is 72 milli-arcsec if the object is located
at 1 kpc
and 12 milli-arcsec if 6 kpc.
These values are well above the
smallest material motion we can measure,
2 to 3 milli-arcsec, in our
methodology that has been proven in our
recent proper-motion
measurements on a proto-planetary nebula,
the Egg Nebula, using the
archived HST/NICMOS near-IR continuum
data. We estimate that the new
distance measurement is of about 10%
error. Once we obtain the distance
to HD 179821, we will construct a radiative transfer model of the object
to constrain physical parameters
of the star and shells with a greater
certainty. Then, we can confront theories
of the stellar evolution with
the newly obtained revelation. In
addition, we can examine if all shells
are moving at the same speed, since
there are multiple shells around HD
179821. It is typically assumed that the expansion of the circumstellar
shells is constant over the lifetime
of the nebula. Our results will
immediately test the validity of this one
of the most fundamental
assumptions in the stellar outflows.
ACS/WFC 10787
Modes of Star Formation and Nuclear Activity in an Early
Universe
Laboratory
Nearby compact galaxy groups are uniquely suited to
exploring the
mechanisms of star formation amid repeated
and ongoing gravitational
encounters, conditions similar to those of
the high redshift universe.
These dense groups host a variety of modes of star
formation, and they
enable fresh insights into the role of
gas in galaxy evolution. With
Spitzer mid-IR observations in hand, we have begun to
obtain high
quality, multi-wavelength data for a
well- defined sample of 12 nearby
{<4500km/s} compact groups covering the full range of
evolutionary
stages. Here we propose to obtain
sensitive BVI images with the ACS/WFC,
deep enough to reach the turnover of
the globular cluster luminosity
function, and WFPC2 U-band and ACS
H-alpha images of Spitzer-identified
regions hosting the most recent star
formation. In total, we expect to
detect over 1000 young star clusters
forming inside and outside
galaxies, more than 4000 old globular
clusters in >40 giant galaxies
{including 16 early-type
galaxies}, over 20 tidal features,
approximately 15 AGNs,
and intragroup gas in most of the 12 groups.
Combining the proposed ACS images with Chandra
observations, UV GALEX
observations, ground-based H-alpha imaging,
and HI data, we will conduct
a detailed study of stellar
nurseries, dust, gas kinematics, and AGN.
ACS/WFC 10760
Black Hole X-ray Novae in M31
We have been carring out a
Chandra {GO+GTO} and HST {GO} program to find
Black Hole X-ray Nova {BHXN} and their optical
counterparts in M31 for
several years. To date we have found
>2 dozen BHXN and 3 HST optical
counterparts for these BHXN. Our results
suggest a rather high ratio of
BH to neutron star {NS} binaries,
or a high duty cycle for the BHXN. We
propose to continue this program, with
the goal of determining the
orbital period distribution and duty
cycles of these BHXN. Current
results yield 3 orbital periods and 2
upper limits. Our proposed
observations will ~double the total number
of periods and therefore
yield sufficient numbers to make a
first approximation of the orbital
period distribution. The orbital
period distribution is the fundamental
observable parameter any binary stellar
evolution models must match, and
the duty cycle is very poorly known
but directly influences the binary
lifetime. M31 is the only galaxy in
which this extra-galactic study of
BHXN is feasible.
ACS/WFC 10583
Resolving the LMC Microlensing
Puzzle: Where Are the Lensing Objects
?
We are requesting 32 HST orbits to help ascertain the
nature of the
population that gives rise to the observed
set of microlensing events
towards the LMC. The SuperMACHO project is an ongoing ground-based
survey on the CTIO 4m that has
demonstrated the ability to detect LMC
microlensing events in real-time via frame
subtraction. The improvement
in angular resolution and
photometric accuracy available from HST will
allow us to 1} confirm that the
detected flux excursions arise from LMC
source stars rather than extended
objects {such as for background
supernovae or AGN}, and 2} obtain reliable baseline flux
measurements
for the objects in their unlensed state. The latter measurement is
important to resolve degeneracies
between the event timescale and
baseline flux, which will yield a
tighter constraint on the microlensing
optical depth.
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:
#17659-0
ESTR Reconditioning (Generic) @ 187/1318z
#18042-1
MA/GN Recorder Dump Test (Generic) @ 187/1630z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 22 22
FGS REacq 20 20
OBAD with Maneuver
81 81
SIGNIFICANT EVENTS: (None)
-
____________________________________________________________
Lynn F. Bassford
Hubble Space Telescope
CHAMP
Lockheed Martin
NASA GSFC PH#: 301-286-2876
"The
Hubble Space Telescope is the astronomical observatory and key to unlocking the
most cosmic mysteries of the past, present and future." -
7/26/6