HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4678
PERIOD COVERED: 5am August 19 - 5am August 20, 2008 (DOY
232/0900z-233/0900z)
OBSERVATIONS SCHEDULED
NIC1 11205
The Effects of Multiplicity on the Evolution of Young
Stellar Objects: A
NICMOS Imaging Study
We propose to use NICMOS to investigate the multiplicity
of young
stellar objects (YSOs) in the Orion B molecular cloud.
Previous
observations with the Spitzer Space Telescope have
revealed a remarkable
star forming filament near the NGC 2068 reflection nebula.
The
population of YSOs associated with the filament exhibit a
surprisingly
wide range of circumstellar evolutionary states, from
deeply embedded
protostars to T Tauri accretion disks. Many of the
circumstellar disks
themselves show evidence for significant dust evolution,
including grain
growth and settling and cleared inner holes, apparently in
spite of the
very young age of these stars. We will estimate the binary
fraction of a
representative sample of objects in these various stages
of evolution in
order to test whether companions may play a significant
role in that
evolution.
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 i
mages. Each observation will need its own CRMAP, as
different SAA
passages leave different imprints on the NICMOS detectors.
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.
WFPC2 11130
AGNs with Intermediate-mass Black Holes: Testing the Black
Hole-Bulge
Paradigm, Part II
The recent progress in the study of central black holes in
galactic
nuclei has led to a general consensus that supermassive
{10^6-10^9 solar
mass} black holes are closely connected with the formation
and
evolutionary history of large galaxies, especially their
bulge
component. Two outstanding issues, however, remain
unresolved. Can
central black holes form in the absence of a bulge? And
does the mass
function of central black holes extend below 10^6 solar
masses?
Intermediate-mass black holes {<10^6 solar masses}, if
they exist, may
offer important clues to the nature of the seeds of
supermassive black
holes. Using the SDSS, our group has successfully
uncovered a new
population of AGNs with intermediate-mass black holes that
reside in
low-luminosity galaxies. However, very little is known
about the
detailed morphologies or structural parameters of the host
galaxies
themselves, including the crucial question of whether they
have bulges
or not. Surprisingly, the majority of the targets of our
Cycle 14 pilot
program have structural properties similar to dwarf
elliptical galaxies.
The statistics from this initial study, however, are
really too sparse
to reach definitive conclusions on this important new
class of black
holes. We wish to extend this study to a larger sample, by
using the
Snapshot mode to obtain WFPC2 F814W images from a parent
sample of 175
AGNs with intermediate- mass black holes selected from our
final SDSS
search. We are particularly keen to determine whether the
hosts contain
bulges, and if so, how the fundamental plane properties of
the host
depend on the mass of their central black holes. We will
also
investigate the environment of this unique class of AGNs.
WFPC2 11221
A Dark Core in Abell 520
We have recently disocovered 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.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11449 - GSacq(2,1,1) failed to RGA control
At
232/23:58:32 the GSacq(2,1,1) scheduled at 232/23:55:35 failed to RGA
control due to scan
step limit exceeded on FGS 2.
Observations
affected: NIC 86 - 107 Proposal ID 11512
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
08
07
FGS
REacq
07
07
OBAD with Maneuver
30
30
SIGNIFICANT EVENTS: (None)