HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science
 
DAILY REPORT      #5048
 
PERIOD COVERED: 5am March 8 - 5am March 9, 2010 (DOY 067/10:00z-068/10:00z)
 
OBSERVATIONS SCHEDULED
 
ACS/WFC 11995
 
CCD Daily Monitor (Part 2)
 
This program comprises basic tests for measuring the read noise and dark
current of the ACS WFC and for tracking the growth of hot pixels. The
recorded frames are used to create bias and dark reference images for
science data reduction and calibration. This program will be executed
four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To
facilitate scheduling, this program is split into three proposals. This
proposal covers 320 orbits (20 weeks) from 1 February 2010 to 20 June
2010.
 
COS/FUV 11895
 
FUV Detector Dark Monitor
 
The purpose of this proposal is to monitor the FUV detector dark rate by
taking long science exposures without illuminating the detector. The
detector dark rate and spatial distribution of counts will be compared
to pre-launch and SMOV data in order to verify the nominal operation of
the detector. Variations of count rate as a function of orbital position
will be analyzed to find dependence of dark rate on proximity to the
SAA. Dependence of dark rate as function of time will also be tracked.
 
COS/NUV 11894
 
NUV Detector Dark Monitor
 
The purpose of this proposal is to measure the NUV detector dark rate by
taking long science exposures with no light on the detector. The
detector dark rate and spatial distribution of counts will be compared
to pre-launch and SMOV data in order to verify the nominal operation of
the detector. Variations of count rate as a function of orbital position
will be analyzed to find dependence of dark rate on proximity to the
SAA. Dependence of dark rate as function of time will also be tracked.
 
COS/NUV 11896
 
NUV Spectroscopic Sensitivity Monitoring
 
The purpose of this proposal is to monitor sensitivity of each NUV
grating mode to detect any changes due to contamination or other causes.
 
NIC2/WFC3/IR 11548
 
Infrared Imaging of Protostars in the Orion A Cloud: The Role of
Environment in Star Formation
 
We propose NICMOS and WFC3/IR observations of a sample of 252 protostars
identified in the Orion A cloud with the Spitzer Space Telescope. These
observations will image the scattered light escaping the protostellar
envelopes, providing information on the shapes of outflow cavities, the
inclinations of the protostars, and the overall morphologies of the
envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron
spectra of 75 of the protostars. Combining these new data with existing
3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured
with the Spitzer Space Telescope, we will determine the physical
properties of the protostars such as envelope density, luminosity,
infall rate, and outflow cavity opening angle. By examining how these
properties vary with stellar density (i.e. clusters vs. groups vs.
isolation) and the properties of the surrounding molecular cloud; we can
directly measure how the surrounding environment influences protostellar
evolution, and consequently, the formation of stars and planetary
systems. Ultimately, this data will guide the development of a theory of
protostellar evolution.
 
S/C 11639
 
Catching Accreting WDs Moving into Their Instability Strip(s)
 
Our past HST studies of the temperatures of 9 accreting, pulsating white
dwarfs in cataclysmic variables show that 3 are in the normal
instability strip for single white dwarfs, but the other 6 are much
hotter (15, 000-16, 500K). This dual strip has been proposed to be due
to mass differences in the white dwarfs related to evolutionary history
and driven by the ionization of different elements in their respective
driving regions. In 2007, GW Lib (the brightest and best studied of the
6 hot accreting pulsators) and V455 And (the brightest and best studied
of the 3 cool accreting pulsators) underwent rare large amplitude dwarf
nova outbursts (known to heat the white dwarf) and their pulsations
disappeared. We propose COS observations to: a) take advantage of the
unprecedented opportunity to view the change in pulsation modes due to
cooling of the white dwarf envelope and b) determine the masses of the
white dwarfs to test the dual strip theory. In addition, a nova that had
its outburst 22 yrs ago has begun non-radial pulsations as it returns to
quiescence. We will use COS to determine its temperature in relation to
the instability strip for the pulsating white dwarfs in dwarf novae.
 
STIS/CC 11845
 
CCD Dark Monitor Part 2
 
Monitor the darks for the STIS CCD.
 
STIS/CC 11847
 
CCD Bias Monitor-Part 2
 
Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and 1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution of hot columns.
 
STIS/CCD 11721
 
Verifying the Utility of Type Ia Supernovae as Cosmological Probes:
Evolution and Dispersion in the Ultraviolet Spectra
 
The study of distant type Ia supernova (SNe Ia) offers the most
practical and immediate discriminator between popular models of dark
energy. Yet fundamental questions remain over possible
redshift-dependent trends in their observed and intrinsic properties.
High-quality Keck spectroscopy of a representative sample of 36
intermediate redshift SNe Ia has revealed a surprising, and unexplained,
diversity in their rest-frame UV fluxes. One possible explanation is
hitherto undiscovered variations in the progenitor metallicity.
Unfortunately, this result cannot be compared to local UV data as only
two representative SNe Ia have been studied near maximum light. Taking
advantage of two new `rolling searches' and the restoration of STIS, we
propose a non-disruptive TOO campaign to create an equivalent comparison
local sample. This will allow us to address possible evolution in the
mean UV spectrum and its diversity, an essential precursor to the study
of SNe beyond z~1.
 
STIS/CCD 11852
 
STIS CCD Spectroscopic Flats C17
 
The purpose of this proposal is to obtain pixel-to-pixel lamp flat
fields for the STIS CCD in spectroscopic mode.
 
WFC3/ACS/UVIS/IR 11570
 
Narrowing in on the Hubble Constant and Dark Energy
 
A measurement of the Hubble constant to a precision of a few percent
would be a powerful aid to the investigation of the nature of dark
energy and a potent "end-to end" test of the present cosmological model.
In Cycle 15 we constructed a new streamlined distance ladder utilizing
high- quality type Ia supernova data and observations of Cepheids with
HST in the near-IR to minimize the dominant sources of systematic
uncertainty in past measurements of the Hubble constant and reduce its
total uncertainty to a little under 5%. Here we propose to exploit this
new route to reduce the remaining uncertainty by more than 30%,
translating into an equal reduction in the uncertainty of the equation
of state of dark energy. We propose three sets of observations to reach
this goal: a mosaic of NGC 4258 with WFC3 in F160W to triple its sample
of long period Cepheids, WFC3/F160W observations of the 6 ideal SN Ia
hosts to triple their samples of Cepheids, and observations of NGC 5584
the host of a new SN Ia, SN 2007af, to discover and measure its Cepheids
and begin expanding the small set of SN Ia luminosity calibrations.
These observations would provide the bulk of a coordinated program aimed
at making the measurement of the Hubble constant one of the leading
constraints on dark energy.
 
WFC3/IR 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
WFC3 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!
 
WFC3/UV/IR 11664
 
The WFC3 Galactic Bulge Treasury Program: Populations, Formation
History, and Planets
 
Exploiting the full power of the Wide Field Camera 3 (WFC3), we propose
deep panchromatic imaging of four fields in the Galactic bulge. These
data will enable a sensitive dissection of its stellar populations,
using a new set of reddening-free photometric indices we have
constructed from broad-band filters across UV, optical, and near-IR
wavelengths. These indices will provide accurate temperatures and
metallicities for hundreds of thousands of individual bulge stars.
Proper motions of these stars derived from multi-epoch observations will
allow separation of pure bulge samples from foreground disk
contamination. Our catalogs of proper motions and panchromatic
photometry will support a wide range of bulge studies.
 
Using these photometric and astrometric tools, we will reconstruct the
detailed star-formation history as a function of position within the
bulge, and thus differentiate between rapid- and extended-formation
scenarios. We will also measure the dependence of the stellar mass
function on metallicity, revealing how the characteristic mass of star
formation varies with chemistry. Our sample of bulge stars with accurate
metallicities will include 12 candidate hosts of extrasolar planets.
Planet frequency is correlated with metallicity in the solar
neighborhood; our measurements will extend this knowledge to a remote
environment with a very distinct chemistry.
 
Our proposal also includes observations of six well-studied globular and
open star clusters; these observations will serve to calibrate our
photometric indices, provide empirical population templates, and
transform the theoretical isochrone libraries into the WFC3 filter
system. Besides enabling our own program, these products will provide
powerful new tools for a host of other stellar-population investigations
with HST/WFC3. We will deliver all of the products from this Treasury
Program to the community in a timely fashion.
 
WFC3/UVIS 11905
 
WFC3 UVIS CCD Daily Monitor
 
The behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from this
proposal, along with those from the anneal procedure (Proposal 11909),
will be used to generate the necessary superbias and superdark reference
files for the calibration pipeline (CDBS).
 
WFC3/UVIS/IR 11644
 
A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into
the Formation of the Outer Solar System
 
The eight planets overwhelmingly dominate the solar system by mass, but
their small numbers, coupled with their stochastic pasts, make it
impossible to construct a unique formation history from the dynamical or
compositional characteristics of them alone. In contrast, the huge
numbers of small bodies scattered throughout and even beyond the
planets, while insignificant by mass, provide an almost unlimited number
of probes of the statistical conditions, history, and interactions in
the solar system. To date, attempts to understand the formation and
evolution of the Kuiper Belt have largely been dynamical simulations
where a hypothesized starting condition is evolved under the
gravitational influence of the early giant planets and an attempt is
made to reproduce the current observed populations. With little
compositional information known for the real Kuiper Belt, the test
particles in the simulation are free to have any formation location and
history as long as they end at the correct point. Allowing compositional
information to guide and constrain the formation, thermal, and
collisional histories of these objects would add an entire new dimension
to our understanding of the evolution of the outer solar system. While
ground based compositional studies have hit their flux limits already
with only a few objects sampled, we propose to exploit the new
capabilities of WFC3 to perform the first ever large-scale
dynamical-compositional study of Kuiper Belt Objects (KBOs) and their
progeny to study the chemical, dynamical, and collisional history of the
region of the giant planets. The sensitivity of the WFC3 observations
will allow us to go up to two magnitudes deeper than our ground based
studies, allowing us the capability of optimally selecting a target list
for a large survey rather than simply taking the few objects that can be
measured, as we have had to do to date. We have carefully constructed a
sample of 120 objects which provides both overall breadth, for a general
understanding of these objects, plus a large enough number of objects in
the individual dynamical subclass to allow detailed comparison between
and within these groups. These objects will likely define the core
Kuiper Belt compositional sample for years to come. While we have many
specific results anticipated to come from this survey, as with any
project where the field is rich, our current knowledge level is low, and
a new instrument suddenly appears which can exploit vastly larger
segments of the population, the potential for discovery -- both
anticipated and not -- is extraordinary.
 
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               9               9
FGS REAcq               6               6
OBAD with Maneuver 6               6
 
SIGNIFICANT EVENTS: (None)