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Daily 3699



 
 
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Old September 21st 04, 05:59 PM
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Default Daily 3699

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3699

PERIOD COVERED: DOY 264

OBSERVATIONS SCHEDULED

ACS/HRC 10180

Ultracompact Blue Dwarfs: Galaxy Formation in the Local Universe?

Recent observations suggest that very low-mass galaxies in the local
universe are still in the process of formation. To investigate this
issue we propose to obtain deep ACS HRC images in the U, V and I bands
of a sample of 11 "ultracompact" blue dwarf galaxies {UCBDs}
identified in the Sloan Digital Sky Survey. These objects are nearby
{z 0.009}, actively star-forming, and have extremely small angular
and physical sizes {d 6" and D 1 kpc}. They also tend to reside in
voids. Our WFPC2 images of the prototype object of this class, POX
186, reveal this tiny object to have a highly disturbed morphlogy
indicative of a recent {within 10^8 yr} collision between two small {~
100 pc} clumps of stars that could represent the long-sought building
blocks predicted by the Press-Schechter model of hierarchical galaxy
formation. This collision has also triggered the formation of a
"super" star cluster {SSC} at the object's core that may be the
progenitor of a globular cluster. POX 186 thus appears to be a very
small dwarf galaxy in the process of formation. This exciting
discovery strongly motivates HST imaging of a full sample of UCBDs in
order to determine if they have morphologies similar to POX 186. HST
images are essential for resolving the structure of these objects,
including establishing the presence of SSCs. HST also offers the only
way to determine their morphologies in the near UV. The spectra of the
objects available from the SDSS will also allow us to measure their
star formation rates, dust content and metallicities. In addition to
potentially providing the first direct evidence of Press-Schechter
building blocks, these data could yield insight into the relationship
between galaxy and globular cluster formation, and will serve as a
test of the recent "downsizing" model of galaxy formation in which the
least massive objects are the last to form.

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 10255

A Never Before Explored Phase Space: Resolving Close White Dwarf / Red
Dwarf Binaries

We propose an ACS Snapshot imaging survey to resolve a well-defined
sample of highly probable white dwarf plus red dwarf close binaries.
These candidates were selected from a search for white dwarfs with
infrared excess from the 2MASS database. They represent unresolved
systems {separations less than approximately 2" in the 2MASS images}
and are distributed over the whole sky. Our HST+ACS observations will
be sensitive to a separation range {1-20 AU} never before probed by
any means. The proposed study will be the first empirical test of
binary star parameters in the post-AGB phase, and cannot be
accomplished from the ground. By resolving as few as 20 of our ~100
targets with HST, we will be able to characterize the distribution of
orbital semi-major axes and secondary star masses.

ACS/HRC/WFC 10061

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS.

ACS/HRC/WFC 9728

Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae

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.

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 10120

The Formation Histories and Dynamical Roles of X-ray Binaries in
Globular Clusters

Close binaries are fundamental to the dynamical stability and
evolution of globular clusters, but large populations have been
extremely difficult to identify. Chandra X-ray images provide a
revolutionary resource, revealing a few to dozens of low-luminosity
X-ray sources in every cluster deeply examined; our own Chandra
programs uniformly study these ubiquitous X-ray sources {close
binaries and their progeny} in 11 clusters. However, definitive
understanding of the nature of the various X-ray subpopulations
requires the identification of optical counterparts, and HST is the
demonstrated key in these crowded environments. We thus propose a
proven, efficient, and uniform, HST multicolor imaging program for
optical identifications in 6 of our clusters with Chandra data
on-hand, but which lack adequate optical images in the HST archive.
The proposed ACS images will permit statistical classifications into
the various subtypes: CVs, qLMXBs, BY Dra's/RS CVn's {and MSPs}. A
unique aspect of our program is that our clusters span a range of
physical properties such as central concentration, cluster size, and
mass--essential ingredients in the formation, evolution, and dynamical
roles of cluster binaries. Exploiting this range of properties, we
have identified a relation that provides the first compelling link
between the number of X-ray sources and the predicted stellar
encounter frequency in globular cluster cores. But further progress in
understanding the details implicit in this relationship {e.g., whether
CVs and qLMXBs formed primarily via stellar encounters, while BY
Dra's/RS CVn's are mainly primordial binaries} demands uniform optical
identifications for multiple clusters, spanning the full range
physical properties.

ACS/WFC 10217

The ACS Fornax Cluster Survey

The two rich clusters nearest to the Milky Way, and the only large
collections of early-type galaxies within ~ 25 Mpc, are the Virgo and
Fornax Clusters. We propose to exploit the exceptional imaging
capabilities of the ACS/WFC to carry out the most comprehensive
imaging survey to date of early-type galaxies in Fornax: the ACS
Fornax Cluster Survey. Deep ACS/WFC images -- in the F475W {g'} and
F850LP {z'} bands -- will be acquired for 44 E, S0, dE, dE, N and dS0
cluster members. In Cycle 11, we initiated a similar program targeting
early-type galaxies in the Virgo Cluster {the ACS Virgo Cluster
Survey; GO-9401}. Our proposed survey of Fornax would yield an
extraordinary dataset which would complement that already in hand for
Virgo, and allow a definitive study of the role played by environment
in the structure, formation and evolution of early-type galaxies and
their globular cluster systems, nuclei, stellar populations, dust
content, nuclear morphologies and merger histories. It would also be a
community resource for years to come and, together with the ACS Virgo
Cluster Survey, constitute one of the lasting legacies of HST.

ACS/WFC/WFPC2 10227

Globular Cluster Systems of Giant, Post-Starburst Shell Ellipticals

Mergers seem to have played a major role in determining the shapes and
dynamics of elliptical galaxies. A few galactic mergers still occur
and offer valuable clues to past evolutionary processes. Young
globular clusters formed during mergers hold strong promise for
age-dating such events, besides helping shed light on the
cluster-formation process itself. With young globulars in ongoing
mergers and ~0.5 Gyr old remnants now well studied {NGC 4038/39, 3256,
7252, and 3921}, we propose to observe 4 bona fide ellipticals
featuring ripples, tidal tails as well as post-starburst spectra {E+A
galaxies: strong Balmer absorption}, which are obvious candidates for
having undergone a dissipative merger 1-4 Gyr ago. If the globulars
formed during mergers are formed with a normal IMF, they should still
be around in large numbers in intermediate-age systems. If that is
indeed the case, it would constitute strong evidence in favor of the
scenario in which metal-rich globulars in 'normal' ellipticals are
formed in merging events. We plan to use these ACS observations to {1}
measure high-accuracy {g-I error of 0.1 mag} colors for clusters as
faint as the peak of the luminosity function {LF} of old globulars,
{2} use these colors to separate first- and second-generation
clusters, and {3} determine the LFs of the two kinds of clusters down
to 1.5 mag past the LF peak for old globulars. Deep dithered g&I-band
images form a crucial part of our observing strategy. When combined
with previous HST studies of globulars in mergers, this study will
yield about a dozen globular cluster systems with age estimates,
enough to make meaningful statements about the influence of mergers in
creating "red'', metal-rich globulars in giant E's and the evolution
of the specific frequency of globular clusters during galactic
mergers.

FGS 9335

Masses of Pre-Main Sequence Binaries

We propose to continue to map the orbits of young star binaries in the
Taurus and Ophiuchus star forming regions. Our goal is to measure
their masses dynamically. This is important because there are still no
low mass young stars with reliably known masses so calculations of
their evolution to the main sequence are uncalibrated.

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
0.7z1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial--but poorly observed--redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

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 10160

The nuclear scattering geometry of Seyfert galaxies

Orientation-based unification schemes are now well-established as the
basis for understanding the relationships between different classes of
AGN. However, our recent study of the optical polarization properties
of Seyfert 1 galaxies indicates that scattered light emerging from
these objects often follows a different path to that in Seyfert 2's,
indicating that the simplest unification geometry is incomplete. We
have developed a generic scattering model for Seyfert nuclei which
includes a compact, equatorial scattering region located within the
circum-nuclear torus and the 'classic' polar scattering region outside
it. We propose to test this model by using NICMOS to make NIR imaging
observations that will allow us to isolate the two scattering regions
within individual objects.

WFPC2 10068

WFPC2 CYCLE 12 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels.

WFPC2 10362

WFPC2 Cycle 13 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth
streak flats to improve the quality of pipeline flat fields for the
WFPC2 UV filter set. These Earth flats will complement the UV earth
flat data obtained during cycles 8-12.

WFPC2/ACS/HRC/WFC 10013

Focus Monitor

The focus of HST is measured from WFPC2/PC and ACS/HRC images of
stars. Multiple exposures are taken in parallel over an orbit to
determine the influence of breathing on the derived mean focus.
Observations are taken of clusters with suitable orientations to
ensure stars appear in all fields.

FLIGHT OPERATIONS SUMMARY:

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

HSTAR 9538: Second FHST Full Maneuver Update (U1,2FM) @ 264/20:52:14Z
failed with Error Box results indicating "2 FAILED" for mnemonics
QEBSTFG0, QEBSTFG1, and QEBSTFG2. GS Acquisition @ 264/20:55:28Z was
successful. Under investigation.

COMPLETED OPS REQs: None

OPS NOTES EXECUTED:
1269-2 Enable Misc EPS Limits @ 264/22:40z

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 14 14
FGS Reacq 05 05
FHST Update 23 22 See Hstar #
9538
LOSS of LOCK


SIGNIFICANT EVENTS:

Set-up and execution of HST PSS 3.4 Development testing scheduled
265/11:00Z - 21:00Z with GDOC, HITT, and SOC using CCS "D" String with
CCS Release xx (intentionally removed) and PRD xx (intentionally
removed). The purpose of this testing is to verify the PSS 3.4
Simulator version can support Communications Module and SI FSW dumps.


 




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