HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT #4632
PERIOD
COVERED: 5am June 13 - 5am June 16, 2008 (DOY 165/0900z-168/0900z)
OBSERVATIONS
SCHEDULED
NIC1/NIC2/NIC3
8795
NICMOS Post-SAA Calibration - CR Persistence Part 6
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 i
mages.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
NIC3
11512
Molecules
in Exoplanet Atmospheres
We
propose to characterize the conditions, composition, and chemistry in
two
transiting exoplanet atmospheres using molecules as probes. This
will
be accomplished through high precision, near-IR spectroscopy during
an
interval that spans the primary and/or secondary eclipse events. We
have
selected the hot-Jovian HD 209458b and the warm-Neptune GJ 436b for
spectroscopy
from 1.4 to 2.5 microns and we expect to detect the
molecules
H2O, CH4, CO, CO2, and NH3. We will infer the atmospheric
temperature-pressure
profiles and determine the abundance of detected
molecules;
this will be done by comparing detailed radiative transfer
models
with emission and transmission spectra of the exoplanet
atmospheres.
Taken together with the existing observations of HD
189733b,
the proposed measurements will probe the diversity of exoplanet
atmospheres
and the effects of radiation from the stellar primary.
NIC3
11332
NICMOS
Cycle 16 Time Dependent Flat Fields
This
proposal obtains sequences of NICMOS narrow, medium and broad band
filter
flat fields for camera 1. In cameras 2 and 3, parallel
observations
will allow us to obtain high S/N flats for all spectral
elements.
WFPC2
11316
HST
Cycle 16 & Pre-SM4 Optical Monitor
This
is a continuation of the Cycle 15 & pre-SM4 Optical Monitor, 11020.
Please
see that proposal for a more complete description of the
observing
strategy. The 6 visits comprising this proposal observe two
single
standard stars with WFPC2/PC in order to establish overall OTA
focal
length for the purposes of focus maintenance. The goal of this
monitoring
before SM4 is to establish a best estimate of the OTA focus
entering
SMOV.
WFPC2
11218
Snapshot
Survey for Planetary Nebulae in Globular Clusters of the Local
Group
Planetary
nebulae {PNe} in globular clusters {GCs} raise a number of
interesting
issues related to stellar and galactic evolution. The number
of
PNe known in Milky Way GCs, 4, is surprisingly low if one assumes
that
all stars pass through a PN stage. However, it is likely that the
remnants
of stars now evolving in Galactic GCs leave the AGB so slowly
that
any ejected nebula dissipates long before the star becomes hot
enough
to ionize it. Thus there should not be ANY PNe in Milky Way
GCs--but
there are four! It has been suggested that these PNe are the
result
of mergers of binary stars within GCs, i.e., that they are
descendants
of blue stragglers. The frequency of occurrence of PNe in
external
galaxies poses more questions, because it shows a range of
almost
an order of magnitude. I propose a Snapshot survey aimed at
discovering
PNe in the GC systems of Local Group galaxies more distant
than
the Magellanic Clouds. These clusters, some of which may be much
younger
than their counterparts in the Milky Way, might contain many
more
PNe than those of our own galaxy. I will use the standard technique
of
emission-line and continuum imaging, which easily discloses PNe.
FGS
11213
Distances
to Eclipsing M Dwarf Binaries
We
propose HST FGS observations to measure accurate distances of 5
nearby
M dwarf eclipsing binary systems, from which model-independent
luminosities
can be calculated. These objects have either poor or no
existing
parallax measurements. FGS parallax determinations for these
systems,
with their existing dynamic masses determined to better than
0.5%,
would serve as model-independent anchor points for the low-mass
end
of the mass-luminosity diagram.
WFPC2/NIC2
11173
Completing
an Accurate Map of M31 Microlensing
The
halo microlensing masses detected in the MACHO survey (claimed to
compose
about 20% of the Galaxy's mass) represent a major enigma in
astrophysics,
one that must be effectively cross-examined by an
independent
test. We have completed a large, densely-sampled survey of
M31
that can reveal in another galaxy such a halo microlensing signal if
it
exists. In a previous HST/ACS+WFPC2 program (GO 10273, Cycle 13, 16
orbits)
we were able to learn considerably more about a subsample of
these
M31 microlensing events. We were pleased to find that in most
cases
we could isolate the source star for each event, find its baseline
flux
and colors (essential for ruling out classes of confusing variable
stars),
test for misidentification of background supernovae, and measure
the
Einstein parameters, which constrain the range of most likely lens
mass.
(These Cycle 13 results are published in The Astrophysical Journal
Letters.)
We propose to finish the job, taking a similar series of
exposures
to more than double the sample of well-constrained
microlensing
events, which together with the larger ground-based sample
for
which we are completing our analyses will provide 20-30 M31 bona
fide
microlensing events observed by HST. This will be done via a series
of
targeted PC exposures, meant to maximize the number of candidates
studied,
one (or two) at a time. A sample of this size and quality
should
be sufficient to settle the issue of a significant contribution
to
the halos of galaxies by stellar-mass lenses. Furthermore, if there
is
a surplus of such microlensing events above what might be expected
from
stars alone, the higher quality of information will allow us to
more
accurately describe the spatial distribution of these lenses. We
will
also complete several unique studies of M31 stellar populations,
both
in support of the microlensing measurement and in their own right.
NIC1/NIC2
11172
Defining
Classes of Long Period Variable Stars in M31
We
propose a thrifty but information-packed investigation {1440
exposures
total} with NICMOS F205W, F160W and F110W providing crucial
information
about Long Period Variables in M31, at a level of detail
that
has recently allowed the discovery of new variable star classes in
the
Magellanic Clouds, a very different stellar population. These
observations
are buttressed by an extensive map of the same fields with
ACS
and WFPC2 exposures in F555W and F814W, and a massive ground-based
imaging
patrol producing well-sampled light curves for more than 400,000
variable
stars. Our primary goal is to collect sufficient NIR data in
order
to analyze and classify the huge number of long-period variables
in
our catalog {see below} through Period- Luminosity {P/L} diagrams. We
will
produce accurate P/L diagrams for both the bulge and a progression
of
locations throughout the disk of M31. These diagrams will be similar
in
quality to those currently in the Magellanic Clouds, with their lower
metallicity,
radically different star formation history, and larger
spread
in distance to the variables. M31 offers an excellent chance to
study
more typical disk populations, in a manner which might be extended
to
more distant galaxies where such variables are still visible, probing
a
much more evenly spread progenitor age distribution than cepheids {and
perhaps
useful as a distance scale alternative or cross- check}. Our
data
will also provide a massive and unique color-magnitude dataset, and
allow
us to confirm the microlensing nature of a large sample of
candidate
lensed sources in M31. We expect that this study will produce
several
important results, among them a better understanding of P/L and
P/L-color
relations for pulsating variables which are essential to the
extragalactic
distance ladder, will view these variables at a common
distance
over a range of metallicities {eliminating the distance-error
vs.
metallicity ambiguity between the LMC and SMC}, allow further
insight
into possible faint-variable mass-loss for higher metallicities,
and
in general produce a sample more typical of giant disk galaxies
predominant
in many studies.
NIC2/WFPC2
11142
Revealing
the Physical Nature of Infrared Luminous Galaxies at 0.3<z<2.7
Using
HST and Spitzer
We
aim to determine physical properties of IR luminous galaxies at
0.3<z<2.7
by requesting coordinated HST/NIC2 and MIPS 70um observations
of
a unique, 24um flux-limited sample with complete Spitzer mid-IR
spectroscopy.
The 150 sources investigated in this program have S{24um}
>
0.8mJy and their mid-IR spectra have already provided the majority
targets
with spectroscopic redshifts {0.3<z<2.7}. The proposed
150~orbits
of NIC2 and 66~hours of MIPS 70um will provide the physical
measurements
of the light distribution at the rest-frame ~8000A and
better
estimates of the bolometric luminosity. Combining these
parameters
together with the rich suite of spectral diagnostics from the
mid-IR
spectra, we will {1} measure how common mergers are among LIRGs
and
ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers
of
z>1 ULIRGs, as in the local Universe. {2} study the co-evolution of
star
formation and blackhole accretion by investigating the relations
between
the fraction of starburst/AGN measured from mid-IR spectra vs.
HST
morphologies, L{bol} and z. {3} obtain the current best estimates of
the
far-IR emission, thus L{bol} for this sample, and establish if the
relative
contribution of mid-to-far IR dust emission is correlated with
morphology
{resolved vs. unresolved}.
WFPC2
11129
The
Star Formation History of the Fornax Dwarf Spheroidal Galaxy
The
Fornax dwarf spheroidal galaxy is one of the most luminous dwarf
satellites
of the Milky Way. It is unusual in many ways: it hosts 5
globular
clusters, shows some relatively young stars, and has faint
sub-structures
which have been interpreted as signs of recent
interactions.
It is thus of great interest to learn the complete star
formation
history {SFH} of Fornax to establish a link between its
evolutionary
path and the predictions from numerical simulations, as a
test
of our understanding of dwarf galaxy evolution. Yet many questions
remain
open. Is the old stellar population made up of stars formed in a
very
early burst, perhaps before the epoch of re-ionization, or the
result
of a more continuous star formation between 13 and 9 Gyr ago ?
How
quickly did Fornax increase its metallicity during its initial
assembly
and during subsequent episodes of star formation ? Are
accretion
episodes required to explain the age-metallicity history of
Fornax
? However, there has never been a comprehensive study of the
global
SFH of the Fornax field based on data of sufficient depth to
unambiguously
measure the age mixture of the stellar populations and
their
spatial variation. We propose to use the WFPC2 to obtain very deep
images
in several fields across the central region of Fornax in order to
reach
the oldest main-sequence turnoffs. The number of fields is
determined
by the need to measure the SFH over different regions with
distinct
kinematics and metallicity. The resolution achievable with HST
is
crucial to answer these questions because, to derive the age
distribution
of the oldest stars, we are interested in I magnitude
differences
of the order 0.2 mag in crowded fields at V=24.5. We will
directly
measure the time variation in star-formation rate over the
entire
galaxy history, from first stars coeval with the Milky Way halo
to
the youngest populations 200 Myr ago. The combination of detailed CMD
analysis
with WFPC2 with our existing metallicity and kinematic
information
will allow us to trace out the early phases of its
evolution.
NIC3
11107
Imaging
of Local Lyman Break Galaxy Analogs: New Clues to Galaxy
Formation
in the Early Universe
We
have used the ultraviolet all-sky imaging survey currently being
conducted
by the Galaxy Evolution Explorer {GALEX} to identify for the
first
time a rare population of low-redshift starbursts with properties
remarkably
similar to high-redshift Lyman Break Galaxies {LBGs}. These
"compact
UV luminous galaxies" {UVLGs} resemble LBGs in terms of size,
SFR,
surface brightness, mass, metallicity, kinematics, dust, and color.
The
UVLG sample offers the unique opportunity of investigating some very
important
properties of LBGs that have remained virtually inaccessible
at
high redshift: their morphology and the mechanism that drives their
star
formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS
in
order to 1} characterize their morphology and look for signs of
interactions
and mergers, and 2} probe their star formation histories
over
a variety of timescales. The images show a striking trend of small-
scale
mergers turning large amounts of gas into vigorous starbursts {a
process
referred to as dissipational or "wet" merging}. Here, we propose
to
complete our sample of 31 LBG analogs using the ACS/SBC F150LP {FUV}
and
WFPC2 F606W {R} filters in order to create a statistical sample to
study
the mechanism that triggers star formation in UVLGs and its
implications
for the nature of LBGs. Specifically, we will 1} study the
trend
between galaxy merging and SFR in UVLGs, 2} artificially redshift
the
FUV images to z=1-4 and compare morphologies with those in similarly
sized
samples of LBGs at the same rest-frame wavelengths in e.g. GOODS,
UDF,
and COSMOS, 3} determine the presence and morphology of significant
stellar
mass in "pre- burst" stars, and 4} study their immediate
environment.
Together with our Spitzer {IRAC+MIPS}, GALEX, SDSS and
radio
data, the HST observations will form a unique union of data that
may
for the first time shed light on how the earliest major episodes of
star
formation in high redshift galaxies came about. This proposal was
adapted
from an ACS HRC+WFC proposal to meet the new Cycle 16 observing
constraints,
and can be carried out using the ACS/SBC and WFPC2 without
compromising
our original science goals.
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 individual
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.
WFPC2
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:
11342
- Reacq(2,0,2) failed to RGA control
The Reacq(2,0,2)scheduled at 166/03:38:49 failed to RGA hold.
There were
no flags. OBAD1 showed errors of V1=-521.21, V2=-807.25,
V3=278.46, and
RSS=1000.42. OBAD2 showed errors of V1=-7.40, V2=-7.41, V3=14.43,
and
RSS=17.83.
Observations affected: NIC 75 -80 Proposal# (11172)A1F-C3-JT and
(11172)A1F-C3-K6
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
20
20
FGS
REacq
24
23
OBAD
with Maneuver 88
88
SIGNIFICANT
EVENTS: (None)