HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4656
PERIOD COVERED: 5am July 18 - 5am July 21, 2008 (DOY
200/0900z-203/0900z)
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.
NIC2 11547
Characterizing Pre-Main Sequence Populations in Stellar
Associations of
the Large Magellanic Cloud
The Large Magellanic Cloud (LMC) offers an extremely rich
sample of
resolved low-mass stars (below 1 Solar Mass) in the act of
formation
that has not been explored sufficiently yet. These
pre-main sequence
(PMS) stars provide a unique snapshot of the star
formation process, as
it is being recorded for the last ~20 Myr, and they give
important
information on the low-mass Initial Mass Function (IMF) of
their host
stellar systems. Studies of young, rich LMC clusters like
30 Doradus are
crowding limited, even at the angular resolution
facilitated by HST in
the optical. To learn more about low-mass PMS stars in the
LMC, one has
to study less crowded regions like young stellar
associations. We propose
to employ WFPC2 to obtain deep photometry (V ~ 25.5 mag)
of four
selected LMC stellar associations in order to perform an
original
optical analysis of their red PMS and blue bright MS
stellar
populations. With these observations we aim at a
comprehensive study,
which will add substantial information on the most recent
star formation
and the IMF in the LMC. The data reduction and analysis
will be
performed with a 2D photometry software package especially
developed by
us for WFPC2 imaging of extended stellar associations with
variable
background. Our targets have been selected optimizing a
combination of
criteria, namely spatial resolution, crowding, low
extinction, nebular
contamination, and background confusion in comparison to
other regions
in the Local Group. Parallel NICMOS imaging will provide
additional
information on near-infrared properties of the stellar
population in the
regions surrounding these systems.
NIC3 11545
A NICMOS Survey of Newly-Discovered Young Massive Clusters
We are on the cusp of a revolution in massive star
research triggered by
2MASS and Spitzer/GLIMPSE, and now is the ideal time to
capitalize on
these projects by performing the first survey of massive
stars in young
stellar clusters throughout the Galactic plane. A search
of the 2MASS
and GLIMPSE surveys has produced over 450 newly-identified
massive
stellar cluster candidates in the Galactic plane which are
hidden from
our view at optical wavelengths due to extinction. Here we
propose a
program of 29 orbits to image the most promising candidate
clusters in
broad and narrow band filters using HST/NICMOS. We will be
complementing
these observations with approved Spitzer and Chandra
programs,
numerous approved and planned ground-based spectroscopic
observations,
and state-of-the-art modeling. We expect to substantially
increase the
numbers of massive stars known in the Galaxy, including
main sequence
stars and post-main sequence stars in the Red Supergiant,
Luminous Blue
Variable and Wolf-Rayet stages. Ultimately, this programme
will address
many of the fundamental topics in astrophysics: the slope
to the initial
mass function (IMF), an upper-limit to the masses of
stars, the
formation and evolution of the most massive stars,
gamma-ray burst (GRB)
progenitors, the chemical enrichment of the interstellar
medium, and
nature of the first stars in the Universe.
NIC3 11333
NICMOS Non-linearity tests
This program incorporates a number of tests to analyze the
count rate
dependent non-linearity seen in NICMOS spectro-photometric
observations.
We will observe a field with stars of a range in
luminosity in NGC3603
with NICMOS in NIC1: F090M, F110W, F140W, F160W NIC2:
F110W, F160W,
F187W, F205W, and F222M NIC3: F110W, F150W, F160W, F175W,
and F222M. We
will repeat the observations with flatfield lamp on,
creating
artificially high count-rates, allowing tests of NICMOS
linearity as
function of count rate. We first take exposures with the
lamp off, then
exposures with the lamp on, and repeat at the end with
lamp off.
Finally, we continue with taking darks during occultation.
We will furthermore observe spectro-photometric standard
P041C using the
G096, G141, and G206 grisms in NIC3, and repeat the lamp
off/on/off test
to artificially create a high background.
ACS/SBC 11324
UV Contamination Monitor
The observations consist of imaging and spectroscopy with
SBC of the
cluster NGC 6681 in order to monitor the temporal
evolution of the UV
sensitivity of the SBC.
WFPC2 11235
HST NICMOS Survey of the Nuclear Regions of Luminous
Infrared Galaxies
in the Local Universe
At luminosities above 10^11.4 L_sun, the space density of
far-infrared
selected galaxies exceeds that of optically selected
galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily
interacting or
merging disk galaxies undergoing enhanced star formation
and Active
Galactic Nuclei {AGN} activity, possibly triggered as the
objects
transform into massive S0 and elliptical merger remnants.
We propose
NICMOS NIC2 imaging of the nuclear regions of a complete
sample of 88
L_IR > 10^11.4 L_sun luminous infrared galaxies in the
IRAS Revised
Bright Galaxy Sample {RBGS: i.e., 60 micron flux density
> 5.24 Jy}.
This sample is ideal not only in its completeness and
sample size, but
also in the proximity and brightness of the galaxies. The
superb
sensitivity and resolution of NICMOS NIC2 on HST enables a
unique
opportunity to study the detailed structure of the nuclear
regions,
where dust obscuration may mask star clusters, AGN and
additional nuclei
from optical view, with a resolution significantly higher
than possible
with Spitzer IRAC. This survey thus provides a crucial
component to our
study of the dynamics and evolution of IR galaxies
presently underway
with Wide-Field, HST ACS/WFC and Spitzer IRAC observations
of these 88
galaxies. Imaging will be done with the F160W filter
{H-band} to examine
as a function of both luminosity and merger stage {i} the
luminosity and
distribution of embedded star clusters, {ii} the presence
of optically
obscured AGN and nuclei, {iii} the correlation between the
distribution
of 1.6 micron emission and the mid-IR emission as detected
by Spitzer
IRAC, {iv} the evidence of bars or bridges that may funnel
fuel into the
nuclear region, and {v} the ages of star clusters for
which photometry
is available via ACS/WFC observations. The NICMOS data,
combined with
the HST ACS, Spitzer, and GALEX observations of this
sample, will result
in the most comprehensive study of merging and interacting
galaxies to
date.
NIC2 11219
Active Galactic Nuclei in Nearby Galaxies: a New View of
the Origin of
the Radio-loud Radio- quiet Dichotomy?
Using archival HST and Chandra observations of 34 nearby
early-type
galaxies {drawn from a complete radio selected sample} we
have found
evidence that the radio-loud/radio-quiet dichotomy is
directly connected
to the structure of the inner regions of their host
galaxies in the
following sense: [1] Radio-loud AGN are associated with
galaxies with
shallow cores in their light profiles [2] Radio-quiet AGN
are only
hosted by galaxies with steep cusps. Since the brightness
profile is
determined by the galaxy's evolution, through its merger
history, our
results suggest that the same process sets the AGN flavor.
This
provides us with a novel tool to explore the co-evolution
of galaxies
and supermassive black holes, and it opens a new path to
understand the
origin of the radio-loud/radio-quiet AGN dichotomy.
Currently our
analysis is statistically incomplete as the brightness
profile is not
available for 82 of the 116 targets. Most galaxies were
not observed
with HST, while in some cases the study is obstructed by
the presence of
dust features. We here propose to perform an infrared
NICMOS snapshot
survey of these 82 galaxies. This will enable us to i}
test the reality
of the dichotomic behavior in a substantially larger
sample; ii} extend
the comparison between radio-loud and radio-quiet AGN to a
larger range
of luminosities.
FGS 11212
Filling the Period Gap for Massive Binaries
The current census of binaries among the massive O-type
stars is
seriously incomplete for systems in the period range from
years to
millennia because the radial velocity variations are too
small and the
angular separations too close for easy detection. Here we
propose to
discover binaries in this observational gap through a
Faint Guidance
Sensor SNAP survey of relatively bright targets listed in
the Galactic O
Star Catalog. Our primary goal is to determine the binary
frequency
among those in the cluster/association, field, and runaway
groups. The
results will help us assess the role of binaries in
massive star
formation and in the processes that lead to the ejection
of massive
stars from their natal clusters. The program will also
lead to the
identification of new, close binaries that will be targets
of long term
spectroscopic and high angular resolution observations to
determine
their masses and distances. The results will also be
important for the
interpretation of the spectra of suspected and newly
identified binary
and multiple systems.
WFPC2 11206
At the Cradle of the Milky Way: Formation of the Most
Massive Field Disk
Galaxies at z>1
We propose to obtain 2 orbit WFPC2 F814W images of a
sample of the 15
most massive galaxies found at $1 < z < 1.3$. These
were culled from
over 20,000 Keck spectra collected as part of DEEP and are
unique among
high redshift massive galaxy samples in being
kinematically selected.
Through a recent HST NICMOS-2 imaging program {GO-10532},
we have
confirmed that these galaxies have regular stellar disks,
and their
emission line kinematics are not due to gradients from
merging
components. These potentially very young galaxies are
likely precursors
to massive local disks, assuming no further merging. The
proposed WFPC2
and existing NIC-2 data provide colors, stellar masses,
and ages of
bulge and disk subcomponents, to assess whether old
stellar bulges and
disks are in place at that time or still being built, and
constrain
their formation epochs. Finally, this sample will yield
the first
statistically significant results on the $z > 1$
evolution of the
size-velocity-luminosity scaling relations, for massive
galaxies at
different wavelengths, and constrain whether this
evolution reflects
stellar mass growth, or passive evolution, of either bulge
or disk
components.
WFPC2 11202
The Structure of Early-type Galaxies: 0.1-100 Effective
Radii
The structure, formation and evolution of early-type
galaxies is still
largely an open problem in cosmology: how does the
Universe evolve from
large linear scales dominated by dark matter to the highly
non-linear
scales of galaxies, where baryons and dark matter both
play important,
interacting, roles? To understand the complex physical
processes
involved in their formation scenario, and why they have
the tight
scaling relations that we observe today {e.g. the
Fundamental Plane}, it
is critically important not only to understand their
stellar structure,
but also their dark-matter distribution from the smallest
to the largest
scales. Over the last three years the SLACS collaboration
has developed
a toolbox to tackle these issues in a unique and
encompassing way by
combining new non-parametric strong lensing techniques,
stellar
dynamics, and most recently weak gravitational lensing,
with
high-quality Hubble Space Telescope imaging and VLT/Keck
spectroscopic
data of early-type lens systems. This allows us to break
degeneracies
that are inherent to each of these techniques separately
and probe the
mass structure of early-type galaxies from 0.1 to 100
effective radii.
The large dynamic range to which lensing is sensitive
allows us both to
probe the clumpy substructure of these galaxies, as well
as their
low-density outer haloes. These methods have convincingly
been
demonstrated, by our team, using smaller pilot-samples of
SLACS lens
systems with HST data. In this proposal, we request
observing time with
WFPC2 and NICMOS to observe 53 strong lens systems from
SLACS, to obtain
complete multi-color imaging for each system. This would
bring the total
number of SLACS lens systems to 87 with completed HST
imaging and
effectively doubles the known number of galaxy-scale
strong lenses. The
deep HST images enable us to fully exploit our new
techniques, beat down
low- number statistics, and probe the structure and
evolution of
early-type galaxies, not only with a uniform data-set an
order of
magnitude larger than what is available now, but also with
a fully
coherent and self-consistent methodological approach!
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.
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.
WFPC2 11156
Monitoring Active Atmospheres on Uranus and Neptune
We propose Snapshot observations of Uranus and Neptune to
monitor
changes in their atmospheres on time scales of weeks and
months. Uranus
equinox is only months away, in December 2007. Hubble
Space Telescope
observations during the past several years {Hammel et al.
2005, Icarus
175, 284 and references therein} have revealed strongly
wavelength-dependent latitudinal structure, the presence
of numerous
visible-wavelength cloud features in the northern hemisphere,
at least
one very long-lived discrete cloud in the southern
hemisphere, and in
2006 the first dark spot ever seen on Uranus. Long-term
ground-based
observations {Lockwood and Jerzekiewicz, 2006, Icarus 180,
442; Hammel
and Lockwood 2007, Icarus 186, 291} reveal seasonal
brightness changes
whose origins are not well understood. Recent near-IR
images of
obtained using adaptive optics on the Keck Telescope,
together with HST
observations {Sromovsky et al. 2003, Icarus 163, 256 and
references
therein} which include previous Snapshot programs {GO
8634, 10170,
10534} show a general increase in activity at south
temperate latitudes
until 2004, when
Further Snapshot observations of these two dynamic planets
will
elucidate the nature of long-term changes in their zonal
atmospheric
bands and clarify the processes of formation, evolution,
and dissipation
of discrete albedo features.
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.
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.
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 28
28
FGS REacq 13
13
OBAD with Maneuver 80
80
SIGNIFICANT EVENTS: (None)