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Daily 3712



 
 
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Old October 8th 04, 06:11 PM
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Default Daily 3712

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3712

PERIOD COVERED: DOY 281

OBSERVATIONS SCHEDULED

ACS/HRC 10199

The Most Massive Galaxies in the Universe: Double Trouble?

We are proposing an HST snapshot survey of 70 objects with velocity
dispersion larger than 350 km/s, selected from the Sloan Digital Sky
Survey. Potentially this sample contains the most massive galaxies in
the Universe. Some of these objects may be superpositions; HST imaging
is the key to determining if they are single and massive or if they
are two objects in projection. The objects which HST imaging shows to
be single objects are interesting because they potentially harbor the
most massive black holes, and because their existence places strong
constraints on galaxy formation models. When combined with ground
based data already in hand, the objects which HST imaging shows are
superpositions provide valuable information about interaction rates of
early-type galaxies as well as their dust content. They also constrain
the allowed parameter space for models of binary gravitational lenses
{such models are currently invoked to explain discrepancies in the
distribution of lensed image flux ratios and separations}.

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/SBC 10183

A Deep Far-UV Search for the Interacting Binary Population in M80

We propose to carry out a deep, far-ultraviolet {FUV}, time-resolved
survey for cataclysmic variables {CVs} and other dynamically-formed
objects in the globular cluster {GC} M80. This will include a search
for FUV counterparts to the 17 Chandra sources in our field of view,
which include 2 LMXBs and 5 X-ray selected CV candidates. Our goal is
to confirm these sources as interacting binaries and find any
additional CVs below the Chandra detection limit. We will achieve this
with 6 orbits of FUV imaging with the ACS/SB, plus one additional
orbit of NUV imaging with ACS/HRC. Since crowding is not a problem in
the FUV, this will yield time-resolved FUV photometry of all blue
objects in the cluster core. Our CV census will be both deep enough to
be essentially complete and ``broad'' enough to involve all of the
following CV characteristics: {1} UV brightness; {2} blue FUV spectral
shape; {3} strong CIV and HeII emission; {4} short time-scale {$sim$
minutes} variability {flickering, WD spin}; {6} intermediate
time-scale {$sim$ hours} variability {orbital variations}; {7} long
time-scale {$sim$ weeks} variability {dwarf nova eruptions}. We will
thus uncover the interacting binary population in M80. In addition,
our survey will detect numerous blue stragglers and hot white dwarfs,
as well as any other blue objects in the central regions of this
cluster.

ACS/WFC 10178

Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A
study in dust grain evolution

The formation of planetary systems is intimately linked to the dust
population in circumstellar disks, thus understanding dust grain
evolution is essential to advancing our understanding of how planets
form. By combining {1} the high resolution polarimetric capabilities
of ACS and NICMOS, {2} powerful 3-D radiative transfer codes, and {3}
observations of objects known to span the earliest stellar
evolutionary phases, we will gain crucial insight into the initial
phases of dust grain growth: evolution away from an ISM distribution.
Fractional polarization is a strong function of wavelength, therefore
by comparing polarimetric images in the optical and infrared, we can
sensitively constrain not only the geometry and optical depth of the
scattering medium, but also the grain size distribution. By observing
objects representative of the earliest evolutionary sequence of YSOs,
we will be able to investigate how the dust population evolves in size
and distribution during the crucial transition from a disk+envelope
system to a disk+star system. The proposed study will help to
establish the fundamental time scales for the initial depletion of
ISM-like grains: the first step in understanding the transformation
from small submicron sized dust grains, to large millimeter sized
grains, and untimely to planetary bodies.

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 z1.25, 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 z1, 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 z1 in the next two
cycles, complementing on-going surveys from the ground at z1, 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/WFC/NIC3 10339

PANS

Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than
they would be in a universe without acceleration. A powerful and
straightforward way to assess the reliability of the SN Ia measurement
and the conceptual framework of its interpretation is to look for
cosmic deceleration at z 1. This would be a clear signature of a
mixed dark-matter and dark-energy universe. Systematic errors in the
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative ``epoch of deceleration'' with SN 1997ff at z
= 1.7, and 3 more at z 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 z
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.

FGS 10106

An Astrometric Calibration of the Cepheid Period-Luminosity Relation

We propose to measure the parallaxes of 10 Galactic Cepheid variables.
When these parallaxes {with 1-sigma precisions of 10% or better} are
added to our recent HST FGS parallax determination of delta Cep
{Benedict et al 2002}, we anticipate determining the Period-Luminosity
relation zero point with a 0.03 mag precision. In addition to
permitting the test of assumptions that enter into other Cepheid
distance determination techniques, this calibration will reintroduce
Galactic Cepheids as a fundamental step in the extragalactic distance
scale ladder. A Period-Luminosity relation derived from solar
metallicity Cepheids can be applied directly to extragalactic solar
metallicity Cepheids, removing the need to bridge with the Large
Magellanic Cloud and its associated metallicity complications.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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.

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.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTAR 9559: GS Acquisition (2,1,2) @ 281/09:56:37Z resulted in FL
backup (2,0,2) due to SSLE on FGS 1. Under investigation.

HSTAR 9560: The second of a pair of FHST Full Maneuver Updates
(U1,3FM) scheduled @ 281/10:47:09 and 10:49:54Z, failed with Error
Box results indicating "3FAILED" for mnemonics QEBSTFG0, QEBSTFG1, and
QEBSTFG2 at AOS 281/11:00Z. A single 486 Status Buffer message 901
was observed @ 281/11:00:13Z. Subsequent GS Acquisition (1,2,1) @
281/10:52:39Z was successful. No science data was affected. FHST Map
@ 281/11:00:55Z had 3-axis (RSS) value ~ 12.000 arcsec. Under
investigation.

COMPLETED OPS REQs:
17282-1 Off-line the +D and -AA SPAs @281/1429z

OPS NOTES EXECUTED: None

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 11 11
FGS Reacq 4 4
FHST Update 17 16 281/1050z
(HSTAR#9560)
LOSS of LOCK


SIGNIFICANT EVENTS:

Successfully completed commanding to bring the +CC SPA back on-line
and the +D SPA offline in the PCU-R and SSM 486 FSW (TRSWCC and
MACROs) @ 281/14:29Z (OR 17282-1 with attached script). The - AA SPA
was kept offline from the previous Charge Optimization configuration,
for a total of ten SA 3 strings offline. Following the uplink, EPS SEs
monitored power system operation from the MOR for two orbits to verify
nominal operation of the TRSWCC (-AA and +D SPA Trim Relays
disconnected, commanded relay order upon Trickle Charge initiation,
etc.). Immediately following the uplink, there were 32 and 27 minutes
of Trickle Charge during the first and second orbits, respectively.
EPS SEs continue to closely monitor the power system performance,
especially battery temperatures and pressures, to assess the effects
of this change.


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