Daily Rpt #4679

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT*** #4679

PERIOD COVERED: 5am August 20 - 5am August 21, 2008 (DOY
233/0900z-234/0900z)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA Calibration - CR Persistence Part 6

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 11237

The Origin of the Break in the AGN Luminosity Function

We propose to use NICMOS imaging to measure rest-frame optical
luminosities and morphological properties of a complete sample of
faint AGN host galaxies at redshifts z ~ 1.4. The targets are drawn
from the VLT-VIMOS Deep Survey, and they constitute a sample of the
lowest luminosity type 1 AGN known at z 1. The spectroscopically
estimated black hole masses are up to an order of magnitude higher
than expected given their nuclear luminosities, implying highly
sub-Eddington accretion rates. This exactly matches the prediction
made by recent theoretical models of AGN evolution, according to which
the faint end of the AGN luminosity function is populated mainly by
big black holes that have already exhausted a good part of their fuel.
In this proposal we want to test further predictions of that
hypothesis, by focusing on the host galaxy properties of our
low-luminosity, low- accretion AGN. If the local ratio between black
hole and bulge masses holds at least approximately at these redshifts,
one expects most of these low-luminosity AGN to reside in fairly big
ellipticals with stellar masses around and above 10^11 solar masses
(in contrast to the Seyfert phenomenon in the local universe). With
NICMOS imaging we will find out whether that is true, implying also a
sensitive test for the validity of the M_BH/M_bulge relation at z ~
1.4.

NIC2 11548

NICMOS Imaging of Protostars in the Orion A Cloud: The Role of
Environment in Star Formation

We propose NICMOS 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.

NIC3 11512

Molecules in Exoplanet Atmospheres

We propose to characterize the conditions, composition, and chemistry
in two transiting exoplanet atmospheres using molecules as probes.
This will be accomplished through high precision, near-IR spectroscopy
during an interval that spans the primary and/or secondary eclipse
events. We have selected the hot-Jovian HD 209458b and the
warm-Neptune GJ 436b for spectroscopy from 1.4 to 2.5 microns and we
expect to detect the molecules H2O, CH4, CO, CO2, and NH3. We will
infer the atmospheric temperature-pressure profiles and determine the
abundance of detected molecules; this will be done by comparing
detailed radiative transfer models with emission and transmission
spectra of the exoplanet atmospheres. Taken together with the
existing observations of HD 189733b, the proposed measurements will
probe the diversity of exoplanet atmospheres and the effects of
radiation from the stellar primary.

WFPC2 11178

Probing Solar System History with Orbits, Masses, and Colors of
Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens
a window into dynamical conditions in the protoplanetary disk where
they formed as well as the history of subsequent events which sculpted
the outer Solar System and emplaced them onto their present day
heliocentric orbits. To date, at least 47 TNBs have been discovered,
but only about a dozen have had their mutual orbits and separate
colors determined, frustrating their use to investigate numerous
important scientific questions. The current shortage of data
especially cripples scientific investigations requiring statistical
comparisons among the ensemble characteristics. We propose to obtain
sufficient astrometry and photometry of 23 TNBs to compute their
mutual orbits and system masses and to determine separate primary and
secondary colors, roughly tripling the sample for which this
information is known, as well as extending it to include systems of
two near-equal size bodies. To make the most efficient possible use of
HST, we will use a Monte Carlo technique to optimally schedule our
observations.

WFPC2 11203

A Search for Circumstellar Disks and Planetary-Mass Companions around
Brown Dwarfs in Taurus

During a 1-orbit program in Cycle 14, we used WFPC2 to obtain the
first direct image of a circumstellar disk around a brown dwarf. These
data have provided fundamental new constraints on the formation
process of brown dwarfs and the properties of their disks. To search
for additional direct detections of disks around brown dwarfs and to
search for planetary-mass companions to these objects, we propose a
WFPC2 survey of 32 brown dwarfs in the Taurus star-forming region.

WFPC2 11221

A Dark Core in Abell 520

We have recently discovered that the rich cluster Abell 520 exhibits
truly extreme multi-wavelength characteristics. The data indicate that
the cluster is the site of a major merger. Our weak lensing analysis,
based on a deep CFHT image, suggests the presence of a massive dark
core that coincides with the central X-ray emission peak, while being
largely devoid of galaxies. Although a displacement between the X-ray
gas and the galaxy/dark matter distribution may be expected in a
merger (e.g. as in the bullet cluster), the dark matter peak without
galaxies cannot be easily explained within the current collisionless
dark matter paradigm. A higher resolution mass map is required to make
further progress, as it will enable us to examine the detailed
structure of the dark matter distribution, as well as improve the
significance of the dark peak. We propose a 3 x 3 WFPC2 mosaic of
interlaced images, where each pointing consists of two sets of F814W
exposures offset by 5.5 pixels. This will precisely pinpoint the
locations of the highest lensing peaks, enhance the comparison with
the Chandra X-ray data, and test physical and geometrical models for
the spatial and thermal structure of this remarkable cluster derived
from our suite of gas+dark matter simulations of head-on/off-axis
cluster mergers.

WFPC2 11544

The Dynamical Legacy of Star Formation

We propose to use WFPC2 to conduct a wide-field imaging survey of the
young cluster IC348. This program, in combination with archival HST
observations, will allow us to measure precise proper motions for
individual cluster members, characterizing the intra-cluster velocity
dispersion and directly studying the dynamical signatures of star
formation and early cluster evolution. Our projected astrometric
precision (~1 mas in each epoch) will allow us to calculate individual
stellar velocities to unprecedented precision (0.5 mas/yr; 1 km/s)
and directly relate these velocities to observed spatial substructure
within the cluster. This survey will also allow us to probe
small-scale star formation physics by searching for high-velocity
stars ejected from decaying multiple systems, expanding our knowledge
of multiplicity in dense environments, and identifying new substellar
and planetary-mass cluster members based on kinematic membership
tests.

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******************** 08************** 08
FGS REacq******************** 07************** 07
OBAD with Maneuver*********** 30************** 30

SIGNIFICANT EVENTS: (None)