HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3786
PERIOD COVERED: DOYs 028 - 030
OBSERVATIONS SCHEDULED
NICMOS 8791
NICMOS Post-SAA calibration - CR Persistence Part 2
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 10451
FGS 2 Points of Light Test for TGM
This proposal acquires S-curves at two locations in each FGS in one
HST orbit. The PUPIL and F583W spectral elements will be used to
observe UPGREN69 in Trans mode.
ACS/WFC 10429
Streaming Towards Shapley: The Mass of the Richest Galaxy
Concentration in the Local Universe
The 600 km/s motion of the Local Group {LG} with respect to the cosmic
microwave background {CMB} is now known to high accuracy. However, its
precise origin remains poorly understood. The contribution to the
motion from the pull of the rich Shapley supercluster at z = 0.048 is
particularly controversial. This extreme mass concentration contains
more than 20 Abell clusters within 35 Mpc of its very rich central
cluster A3558, and is recognized as both the optically richest and the
most X-ray luminous structure in the local {z < 0.1} universe. Yet,
published values for the mass of Shapley continue to differ by an
order of magnitude, and recent estimates of its pull on the LG range
from negligible {20 km/s} to highly significant {300 km/s or more}.
Here we propose to resolve this key issue by using ACS to measure
high-precision surface brightness fluctuation {SBF} distances in order
to make a direct measurement of the infall towards Shapley. We will
target three Shapley foreground clusters where the infall is expected
to be high {possibly 1000 km/s or more}, as well as the Shapley core,
in order to test the assumption that it is at rest in the CMB. Prior
to ACS, the Shapley region was unreachable for SBF, but ACS doubles
the distance range of the SBF method with HST, enabling the distances
to be measured to the required accuracy. The proposed measurements
will place a firm limit on the largest mass fluctuation in the nearby
universe and finally determine its contribution to the observed CMB
dipole.
ACS/WFC 10420
The assembly of a massive galaxy cluster: The 4/h Mpc filament feeding
We propose a deep ACS/WFC F606W+F814W mosaic of the massive cluster
MACSJ0717.5+3745 at z=0.55 in order to obtain the first direct
detection of cluster evolution through infall of matter along
large-scale filaments. Existing optical, X-ray, and groundbased
weak-lensing data show strong evidence of galaxy groups and dark
matter in a coherent structure spanning at least 10 arcmin {4/h Mpc,
LCDM} in the plane of the sky. The size of this object rules out prior
interaction between the groups and the cluster, thus making it a prime
candidate for a genuine filament as opposed to a merger remnant. The
proposed observation will 1} allow the first direct measurement of the
dark matter content and mass distribution along a large-scale filament
via weak lensing, and 2} provide, through galaxy morphology and
resolved colour information, unprecedented insights into the physical
processes and environmental effects governing the transition from
field to cluster galaxies.
ACS/HRC/WFC 10370
CCD Hot Pixel Annealing
Hot pixel annealing will continue to be performed once every 4 weeks.
The CCD TECs will be turned off and heaters will be activated to bring
the detector temperatures to about +20C. This state will be held for
approximately 12 hours, after which the heaters are turned off, the
TECs turned on, and the CCDs returned to normal operating condition.
To assess the effectiveness of the annealing, a bias and four dark
images will be taken before and after the annealing procedure for both
WFC and HRC. The HRC darks are taken in parallel with the WFC darks.
The charge transfer efficiency {CTE} of the ACS CCD detectors declines
as damage due to on-orbit radiation exposure accumulates. This
degradation has been closely monitored at regular intervals, because
it is likely to determine the useful lifetime of the CCDs. We will now
combine the annealling activity with the charge transfer efficiency
monitoring and also merge into the routine dark image collection. To
this end, the CTE monitoring exposures have been moved into this
proposal . All the data for this program is acquired using internal
targets {lamps} only, so all of the exposures should be taken during
Earth occultation time {but not during SAA passages}. This program
emulates the ACS pre-flight ground calibration and post-launch SMOV
testing {program 8948}, so that results from each epoch can be
directly compared. Extended Pixel Edge Response {EPER} and First Pixel
Response {FPR} data will be obtained over a range of signal levels for
both the Wide Field Channel {WFC}, and the High Resolution Channel
{HRC}.
ACS/HRC/WFC 10367
ACS CCDs daily monitor- cycle 13 - part 1
This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS.
ACS/HRC 10244
Coronagraphic imaging of Eta Corvus: a newly discovered debris disk at
18 pc
Debris disks are one of the final stages in the evolution of planetary
systems. High resolution imaging of debris disks has been instrumental
to our understanding of the status of planet formation in these
systems. The detection of clumps and asymmetries has even led to the
detection of unseen planets. However, just six resolved disks exist in
the literature. Eta Crv is now the seventh debris disk confirmed with
imaging, and was discovered in a recent sub-mm survey of nearby stars.
Its proximity {18 pc} and similarity to Beta Pic, one of the "big
four" Vega-type disks, makes it an excellent candidate for a high
resolution coronagraphic study of its disk structure. Modeling of this
structure at many wavelengths will set hard constraints on its unseen
planetary system and the distribution of particles from micron to
kilometer in size, thus significantly extending our understanding of
the planet formation processes in debris disks
NIC/NIC3 10226
The NICMOS Grism Parallel Survey
We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7
ACS/WFC 10210
Groups of Dwarf Galaxies: Pools of Mostly Dark Matter?
Within 5 Mpc, there are 6 groups with well-known luminous galaxies but
there also appears to be a comparable number of groups containing only
dwarfs. If these dwarf entities are truly bound then M/L values are an
order of magnitude higher than values found for groups with luminous
spiral galaxies. There are theoretical reasons to anticipate that low
mass halos may frequently be mostly dark. The dynamical influence of
low mass halos is negligible in familiar groups with luminous members.
By contrast, a study of the dynamics of `groups of dwarfs' may provide
direct evidence of the existence of dark matter potential wells with
few baryons. The goal of the present study is to gather detailed
information on the 3-D distribution of dwarf galaxies suspected to lie
within 7 groups of dwarfs within 5 Mpc. Distances with 7% relative
accuracy can be measured with the Tip of the Giant Branch method with
ACS and integrations within 1 orbit per target.
ACS/WFC/NIC2 10189
PANS-Probing Acceleration Now with Supernovae
Type Ia supernovae {SNe Ia} provide the most direct evidence for an
accelerating Universe, a result widely attributed to dark energy.
Using HST in Cycle 11 we extended the Hubble diagram with 6 of the 7
highest-redshift SNe Ia known, all at z>1.25, providing conclusive
evidence of an earlier epoch of cosmic deceleration. The full sample
of 16 new SNe Ia match the cosmic concordance model and are
inconsistent with a simple model of evolution or dust as alternatives
to dark energy. Understanding dark energy may be the biggest current
challenge to cosmology and particle physics. To understand the nature
of dark energy, we seek to measure its two most fundamental
properties: its evolution {i.e., dw/dz}, and its recent equation of
state {i.e., w{z=0}}. SNe Ia at z>1, beyond the reach of the ground
but squarely within the reach of HST with ACS, are crucial to break
the degeneracy in the measurements of these two basic aspects of dark
energy. The SNe Ia we have discovered and measured with HST in Cycle
11, now double the precision of our knowledge of both properties. Here
we propose to quadruple the sample of SNe Ia at z>1 in the next two
cycles, complementing on-going surveys from the ground at z<1, and
again doubling the precision of dark energy constraints. Should the
current best fit model prove to be the correct one, the precision
expected from the current proposal will suffice to rule out a
cosmological constant at the 99% confidence level. Whatever the
result, these objects will provide the basis with which to extend our
empirical knowledge of this newly discovered and dominant component of
the Universe, and will remain one of the most significant legacies of
HST. In addition, our survey and follow-up data will greatly enhance
the value of the archival data within the target Treasury fields for
galaxy studies.
ACS/HRC 10185
When does Bipolarity Impose itself on the Extreme Mass Outflows from
AGB Stars? An ACS SNAPshot Survey
Essentially all well-characterized preplanetary nebulae {PPNe} --
objects in transition between the AGB and planetary nebula
evolutionary phases - are bipolar, whereas the mass-loss envelopes of
AGB stars are strikingly spherical. In order to understand the
processes leading to bipolar mass-ejection, we need to know at what
stage of stellar evolution does bipolarity in the mass-loss first
manifest itself? Our previous SNAPshot surveys of a PPNe sample {with
ACS & NICMOS} show that roughly half our targets observed are
resolved, with well-defined bipolar or multipolar morphologies.
Spectroscopic surveys of our sample confirm that these objects have
not yet evolved into planetary nebulae. Thus, the transformation from
spherical to aspherical geometries has already fully developed by the
time these dying stars have become preplanetary nebulae. From this new
and surprising result, we hypothesize that the transformation to
bipolarity begins during the very late AGB phase, and happens very
quickly, just before, or as the stars are evolving off the AGB. We
propose to test this hypothesis quantitatively, through a SNAPshot
imaging survey of very evolved AGB stars which we believe are nascent
preplanetary nebulae; with our target list being drawn from published
lists of AGB stars with detected heavy mass-loss {from millimeter-wave
observations}. This survey is crucial for determining how and when the
bipolar geometry asserts itself. Supporting kinematic observations
using long-slit optical spectroscopy {with the Keck}, millimeter and
radio interferometric observations {with OVRO, VLA & VLBA} are being
undertaken. The results from this survey {together with our previous
work} will allow us to draw general conclusions about the onset of
bipolar mass-ejection during late stellar evolution, and will provide
crucial input for theories of post-AGB stellar evolution. Our survey
will produce an archival legacy of long-standing value for future
studies of dying stars.
ACS/HRC 10182
Towards a Comprehensive Understanding of Type Ia Supernovae: The
Necessity of UV Observations
Type Ia supernovae {SNe Ia} are very important to many diverse areas
of astrophysics, from the chemical evolution of galaxies to
observational cosmology which led to the discovery of dark energy and
the accelerating Universe. However, the utility of SNe Ia as
cosmological probes depends on the degree of our understanding of SN
Ia physics, and various systematic effects such as cosmic chemical
evolution. At present, the progenitors of SNe Ia and the exact
explosion mechanisms are still poorly understood, as are evolutionary
effects on SN Ia peak luminosities. Since early-time UV spectra and
light curves of nearby SNe Ia can directly address these questions, we
propose an approach consisting of two observational components: {1}
Detailed studies of two very bright, young, nearby SNe Ia with HST UV
spectroscopy at 13 epochs within the first 1.5 months after discovery;
and {2} studies of correlations with luminosity for five somewhat more
distant Hubble-flow SNe Ia, for which relative luminosities can be
determined with precision, using 8 epochs of HST UV spectroscopy
and/or broad-band imaging. The HST data, along with extensive
ground-based optical to near-IR observations, will be analyzed with
state-of-the-art models to probe SN Ia explosion physics and constrain
the nature of the progenitors. The results will form the basis for the
next phase of precision cosmology measurements using SNe Ia, allowing
us to more fully capitalize on the substantial past {and future}
investments of time made with HST in observations of high-redshift SNe
Ia.
NIC2 10177
Solar Systems In Formation: A NICMOS Coronagraphic Survey of
Protoplanetary and Debris Disks
Until recently, despite decades of concerted effort applied to
understanding the formation processes that gave birth to our solar
system, the detailed morphology of circumstellar material that must
eventually form planets has been virtually impossible to discern. The
advent of high contrast, coronagraphic imaging as implemented with the
instruments aboard HST has dramatically enhanced our understanding of
natal planetary system formation. Even so, only a handful of evolved
disks {~ 1 Myr and older} have been imaged and spatially resolved in
light scattered from their constituent grains. To elucidate the
physical processes and properties in potentially planet-forming
circumstellar disks, and to understand the nature and evolution of
their grains, a larger spatially resolved and photometrically reliable
sample of such systems must be observed. Thus, we propose a highly
sensitive circumstellar disk imaging survey of a well-defined and
carefully selected sample of YSOs {1-10 Myr T Tau and HAeBe stars} and
{> app 10 Myr} main sequence stars, to probe the posited epoch of
planetary system formation, and to provide this critically needed
imagery. Our resolved images will shed light on the spatial
distributions of the dust in these thermally emissive disks. In
combination with their long wavelength SEDs the physical properties of
the grains will be discerned, or constrained by our photometrically
accurate surface brightness sensitivity limits for faint disks which
elude detection. Our sample builds on the success of the exploratory
GTO 7233 program, using two-roll per orbit PSF-subtracted NICMOS
coronagraphy to provide the highest detection sensitivity to the
smallest disks around bright stars which can be imaged with HST. Our
sample will discriminate between proposed evolutionary scenarios while
providing a legacy of cataloged morphologies for interpreting mid- and
far-IR SEDs that the recently launched Spitzer Space Telescope will
deliver.
NIC2 10176
Coronagraphic Survey for Giant Planets Around Nearby Young Stars
A systematic imaging search for extra-solar Jovian planets is now
possible thanks to recent progress in identifying "young stars near
Earth". For most of the proposed young {<~ 30 Myrs} and nearby {<~ 60
pc} targets, we can detect a few Jupiter-mass planets as close as a
few tens of AUs from the primary stars. This represents the first time
that potential analogs of our solar system - that is planetary systems
with giant planets having semi-major axes comparable to those of the
four giant planets of the Solar System - come within the grasp of
existing instrumentation. Our proposed targets have not been observed
for planets with the Hubble Space Telescope previously. Considering
the very successful earlier NICMOS observations of low mass brown
dwarfs and planetary disks among members of the TW Hydrae Association,
a fair fraction of our targets should also turn out to posses low mass
brown dwarfs, giant planets, or dusty planetary disks because our
targets are similar to {or even better than} the TW Hydrae stars in
terms of youth and proximity to Earth. Should HST time be awarded and
planetary mass candidates be found, proper motion follow-up of
candidate planets will be done with ground-based AOs.
NIC2 10173
Infrared Snapshots of 3CR Radio Galaxies
Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain NICMOS infrared images of 3CR sources with z<0.3 as a major
enhancement to an already superb dataset. We aim to deshroud dusty
galaxies, study the underlying host galaxy free from the distorting
effects of dust, locate hidden regions of star formation and establish
the physical characteristics of the dust itself. We will measure
frequency and spectral energy distributions of point-like nuclei,
expected to be stronger and more prevalent in the IR, seek spectral
turnovers in known synchrotron jets and find new jets. We will
strongly test unified AGN schemes and merge these data with existing
X-ray to radio observations. The resulting database will be an
incredibly valuable resource to the astronomical community for years
to come.
NIC2 10172
Our Galaxy's most promising Super Star Cluster candidate, Westerlund
1: Tip of the Iceberg?
Recent ground-based observations have revealed that the highly
reddened Galactic cluster Westerlund 1 is the current best and by far
the nearest "Young Massive Star Cluster" {YSC} candidate, i.e. a young
{< 10 Myr}, dense and massive {> 10, 000 Mo} object of which until
recently 30 Doradus in the LMC was believed to be the nearest example.
However, extrapolations of the locally derived cluster luminosity
function indicate that perhaps up to a hundred similar objects should
exist within the Galaxy. The close-up view of a YSC provided by
Westerlund 1 allows us to obtain an unprecedented glimpse of the
process of massive cluster formation, evolution and fate, which are
among the very key issues in modern astrophysics. Utilising deep ACS
and NICMOS imaging and sophisticated N-body and Monte Carlo
simulations, we will address key questions regarding Westerlund 1's
nature, formation and dynamical evolution. These include, What are the
initial conditions with which Westerlund 1 was born? To what degree
was mass segregation really primordial? Has the binary fraction
changed during the short cluster lifetime? Do we expect the cluster to
have a population of stellar-mass black holes? Does the cluster
harbour an intermediate-mass black hole in its core? Is Westerlund 1
unique as a Galactic YSC? How similar is the cluster to the massive
"Arches" and "Quintuplet" Galactic Centre clusters, and to 30 Doradus?
With an expected life-span of > 100 Myr, it is conceivable that there
should be more YSCs like Westerlund 1 in the Galactic disk. Our
dynamical simulations will help us determine the ultimate fate of such
clusters, allowing us to at least begin to answer the question of
Westerlund 1's uniqueness in the context of the Galaxy's stellar
populations.
NIC2 10169
Star Formation in Luminous Infrared Galaxies: giant HII Regions and
Super Star Clusters
Luminous Infrared Galaxies {LIRGs, LIR = 10^11-10^12Lsol} and
Ultraluminous Infrared Galaxies {LIR>10^12Lsol} account for
approximately 75% of all the galaxies detected in the mid-infrared in
the redshift range z=0-1.5. In the local universe it is found that
LIRGs are predominantly powered by intense star formation {SF}.
However, the physical conditions and processes governing such dramatic
activity over scales of tens to a few hundred parsecs are poorly
known. In the last decade HST has been playing a significant role,
mainly with the discovery of super star clusters {SSCs}, and more
recently, giant HII regions. Based on observations of a few LIRGs, we
found that these giant HII regions and associated SSCs appear to be
more common in LIRGs than in normal galaxies, and may dominate the
star formation activity in LIRGs. A larger sample is required to
address fundamental questions. We propose an HST/NICMOS targeted
campaign of a volume limited sample {v<5200km/s} of 24 LIRGs. This
proposal will probe the role of giant HII regions in the overall
energetics of the current star formation, their relation to SSCs, and
the dependence of star formation properties on other parameters of
LIRGs. Such detailed knowledge of the SF properties of LIRGs in the
local universe is essential for understanding galaxies at high
redshift.
NIC1 10143
Ultracool companions to the nearest L dwarfs
We propose to conduct the most sensitive survey to date for low mass
companions to nearby L dwarfs. We will use NICMOS to image targets
drawn from a volume-complete sample of 70 L dwarfs within 20 parsecs.
The combination of infrared imaging and proximity will allow us to
search for T dwarf companions at separations as small as 1.6 AU. This
is crucial, since no ultracool binaries are currently known with
separations exceeding 15 AU. Only 10 dwarfs in this sample have
previous HST observations primarily at optical wavelengths. With the
increased sensitivity of our survey, we will provide the most
stringent test to date of brown dwarf models which envisage formation
as ejected stellar embryos. In addition, our observations will be
capable of detecting binaries with mass ratios as low as 0.3, and will
therefore also test the apparent preference for equal-mass ultracool
binaries. Finally, our observations offer the best prospect to date of
detecting companions significantly cooler than the coolest t dwarf
currently known.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None
COMPLETED OPS REQs:
17363-0 Null Genslews for Proposal 10244 Slots 8-14 (No Commanding
Needed) @028/1658z
OPS NOTES EXECUTED: None
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 35 35
FGS Reacq 18 18
FHST Update 36 36
LOSS of LOCK
SIGNIFICANT EVENTS: None
