Daily # 3976

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3976

PERIOD COVERED: UT October 27, 2005 (DOY 300)

OBSERVATIONS SCHEDULED

ACS/HRC 10564

Resolving Ultracool White Dwarf Binaries

We propose an ACS/HRC imaging survey of the coolest white dwarfs known
in order to search for binarity. Current models fail to match observed
spectral energy distributions of these sub- 4000K stellar remnants,
consistently predicting much lower luminosities than observed. A
possible explanation is that they are binary in nature. Because these
cool degenerates have no spectral features, the only way to
investigate their apparent overluminosity is with very high resolution
imaging, which can only be done with HST {these stars are far too
faint to be observed with adaptive optics on the ground}. Optical
wavelengths are ideal because the spectral energy distributions of
these old degenerates peak near 600 nm. With the F435W filter we will
be able to partially resolve equally luminous binaries as close as
0.02", which corresponds to within 0.6 AU for over half of the 12
proposed target stars. The collected data will be critical in
determining whether these stars represent the oldest white dwarfs in
the solar neighborhood.

ACS/HRC/WFC 10548

Near-UV Snapshot Survey of Low Luminosity AGNs

Low-luminosity active galactic nuclei {LLAGNs} comprise ~30% of all
bright galaxies {B12.5} and are the most common type of AGN. These
include low-luminosity Seyfert galaxies, LINERs, and transition-type
objects {TOs, also called weak-[OI] LINERs}. What powers them is still
at the forefront of AGN research. To unveil the nature of the central
source we propose a near-UV snapshot survey of 50 nearby LLAGNs using
ACS/HRC and the filter {F330W}, a configuration which is optimal to
detect faint star forming regions around their nuclei. These images
will complement optical and near-IR images available in the HST
archive, providing a panchromatic atlas of the inner regions of these
galaxies, which will be used to study their nuclear stellar
population. Our main goals are to: 1} Investigate the presence of
nuclear unresolved sources that can be attributed to an AGN; 2}
Determine the frequency of nuclear and circumnuclear stellar clusters,
and whether they are more common in Transition Objects {TOs} than in
LINERs; 3} Characterize the sizes, colors, luminosities, masses and
ages of these clusters; 4} Derive the luminosity function of star
clusters and study their evaporation over time in the vicinity of
AGNs. Finally, the results of this project will be combined with those
of a previous similar one for Seyfert galaxies in order to compare the
nature of the nuclear sources and investigate if there could be an
evolution from Seyferts to TOs and LINERs. By adding UV images to the
existing optical and near-IR ones, this project will also create an
extremely valuable database for astronomers with a broad range of
scientific interests.

ACS/SBC 10506

Coordinated observations of Saturn's auroral dynamic morphology and
Cassini plasma measurements

Planetary FUV aurora is the most spectacular signature of the
electrodynamical coupling between the solar wind, the planet's
magnetic field, and its atmosphere. Saturn's magnetosphere has
similarities both with the Earth's magnetosphere, which is 'open' to
solar wind interaction and Jupiter's relatively 'closed' case with its
large internal sources of plasma. HST observations of Saturn's aurora
have shown a much more complex and dynamic morphology than
anticipated: a frequent 'spiral' structure, a changing size of the
oval in response to variations of the solar wind dynamics pressure,
and large brightness changes in a few ten of minutes following
compression of the magnetosphere by the solar wind. In addition, the
global morphology and some spots move at 70% of the planetary
co-rotation, while some other features appear nearly fixed in local
time. Recently, ideas have emerged to account for Saturn's aurora
specificities, although many aspects are still not understood due to
the paucity of observational data. Electric current models suggest
that the main oval is located at the limit between closed and open
magnetic field lines, near the magnetopause. The availability of
Cassini in Saturn's magnetic environment now offers a unique
opportunity for collaborative science. We thus propose to test the
relationship between the aurora and conditions at Saturn's
magnetopause {MP} boundary. We plan to image the FUV aurora with ACS
at times of inbound Cassini crossing of the MP from the upstream solar
wind/magnetosheath region into the middle magnetosphere during an
inbound segment of a Cassini's orbit. FUV images will also reveal
whether the main oval changes its size over the interval, possibly
indicating evidence for changes in the amount of open flux in the
system. These HST images of the aurora simultaneous with in situ
measurements of the plasma characteristics and electrodynamics inside
the magnetosphere are critical to obtain key observational tests and
constraints to future ideas and models of Saturn's auroral
precipitation and magnetospheric processes involved.

ACS/SBC 10739

Internal Flat Field Stability

The stability of the CCD flat fields will be monitored using the
calibration lamps and a sub-sample of the filter set. For the SBC
imaging filters, differences in the low-frequency flat field structure
with wavelength will be assessed. New high signal P-flats will be
obtained for the SBC prisms.

ACS/WFC 10588

The Host Galaxies of Post-Starburst Quasars

We propose to use ACS to conduct a snapshot imaging survey of
post-starburst quasars now being discovered in signficant numbers by
the Sloan Digital Sky Survey. Post-starburst quasars are broad-lined
AGN that also possess Balmer jumps and high-n Balmer absorption lines
indicative of luminous stellar populations on order of 100 Myr old.
These objects, representing a few percent of the z 0.5 quasar
population, may be an evolutionary stage in the transition of
ultraluminous infrared galaxies into normal quasars, or a type of
galaxy interaction that triggers both star formation and nuclear
activity. These sources may also illustrate how black hole mass/bulge
mass correlations arise. Ground-based imaging of individual
poststarburst quasars has revealed merger remnants, binary systems,
and single point sources. Our ACS snapshots will enable us to
determine morphologies and binary structure on sub-arcsecond scales
{surely present in the sample and impossible to do without HST}, as
well as basic host galaxy properties. We will be looking for
relationships among morphology, particularly separation of double
nuclei, the starburst age, the quasar black hole mass and accretion
rate, that will lead to an understanding of the triggering activity
and mutual evolution. This project will bring quantitative data and
statistics to the previously fuzzy and anecdotal topic of the
"AGN-starburst connection" and help test the idea that post-starburst
quasars are an early evolutionary stage of normal quasars.

ACS/WFC/NIC3/WFPC2 10530

Probing Evolution And Reionization Spectroscopically {PEARS}

While imaging with HST has gone deep enough to probe the highest
redshifts, e.g. the GOODS survey and the Ultra Deep Field,
spectroscopic identifications have not kept up. We propose an ACS
grism survey to get slitless spectra of all sources in a wide survey
region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field
in the HUDF reaching sources up to z =28 magnitude. The PEARS survey
will: {1} Find and spectrocopically confirm all galaxies between
z=4-7. {2} Probe the reionization epoch by robustly determining the
luminosity function of galaxies and low luminosity AGNs at z = 4 - 6.
With known redshifts, we can get a local measure of star formation and
ionization rate in case reionization is inhomogeneous. {3} Study
galaxy formation and evolution by finding galaxies in a contiguous
redshift range between 4 z 7, and black hole evolution through a
census of low-luminosity AGNs. {4} Get a robust census of galaxies
with old stellar populations at 1 z 2.5, invaluable for checking
consistency with heirarchical models of galaxy formation. Fitting
these galaxies' spectra will yield age and metallicity estimates. {5}
Study star-formation and galaxy assembly at its peak at 1 z 2 by
identifying emission lines in star-forming galaxies, old populations
showing the 4000A break, and any combination of the two. {6} Constrain
faint white dwarfs in the Galactic halo and thus measure their
contribution to the dark matter halo. {7} Derive spectro-photometric
redshifts by using the grism spectra along with broadband data. This
will be the deepest unbiased spectroscopy yet, and will enhance the
value of the multiwavelength data in UDF and the GOODS fields to the
astronomical community. To this end we will deliver reduced spectra to
the HST archives.

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 10620

Massive Star Formation and the Proper Motions of the OMC-1 Molecular
Hydrogen Fingers

The Orion Molecular Cloud OMC-1 is by far the nearest region of
massive star formation, and as such provides a laboratory for studying
massive star formation with unprecedented detail. Using NICMOS, eight
years ago our group discovered unique molecular hydrogen 'fingers'
emanating from the IRc2 area. We propose new NICMOS imaging of the
same region to compare with our earlier results. This will determine
spatial motions to ~3 AU/year. Using the two data sets, we will: 1}
bound the age range of the features and thus address whether all the
molecular hydrogen features were produced in a single event - such as
an explosion or a stellar merger - or in multiple events/steady
outflow; 2} limit the location of the outflow source{s}, which remain
to be identified despite sub-arcsecond imaging at thermal infrared
wavelengths; and 3} characterize inhomogeneities on the 100 AU scale.
Together these findings will significantly constrain how massive star
formation proceeds in OMC-1. NICMOS achieves the highest quality,
near-infrared images for diffuse objects in crowded regions. Because
of the complexity of the OMC-1 region, and the difficulty in using
Adaptive Optics to measure small position shifts for diffuse, low
contrast objects, these high precision proper motion measurements
require the stable PSF, high Strehl ratio, and low response in the PSF
wings which HST/NICMOS uniquely provides.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

9986 - GSAcq (1,2,1) failed due to search radius limit exceeded on
FGS1 @ 300/0913z GSAcq (1,2,1) scheduled @ 300/09:08:18 failed due to
search radius limit exceeded on FGS1. Received ESB "a05" Exceeded SRL.
OBAD 1 @ 300/08:40:52 = V1 -10.92, V2 -443.85, V3 -16.05, RSS 444.27
OBAD 2 @ 300/08:58:32 = V1 -18.45, V2 -15.73, V3 -1092, RSS 26.60
Following MAP @ 300/09:15:38 = V1 15.83, V2 54.45, V3 20.14, RSS 60.18

9987 - GSAcq (1,2,1) failed due to search radius limit exceeded on
FGS1 @ 300/1537z GSacq(1,2,1) scheduled at 300/15:32:08 failed due to
search radius limit exceeded on FGS 1. The OBADs showed errors of:
OBAD1 - V1= -842.94, V2= 4214.59, V3 = -1915.90 RSS= 4705.74 OBAD2 -
V1= -57.97, V2= 27.22, V3= -51.87, RSS= 82.42 The map at 15:39:28
showed errors of: V1= 58.75, V2= 64.71, V3= 54.93, RSS= 103.23

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 10 9 300/1537z
(HSTAR 9987)
FGS
REacq 4 3 300/0913z
(HSTAR 9986)
OBAD with Maneuver 27 27

SIGNIFICANT EVENTS: (None)