HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4628
PERIOD
COVERED: 5am June 09 - 5am June 10, 2008 (DOY161/0900z-162/0900z)
OBSERVATIONS
SCHEDULED
WFPC2
10583
Resolving
the LMC Microlensing Puzzle: Where Are the Lensing Objects?
We
are requesting 32 HST orbits to help ascertain the nature of the
population
that gives rise to the observed set of microlensing events
towards
the LMC. The SuperMACHO project is an ongoing ground-based
survey
on the CTIO 4m that has demonstrated the ability to detect LMC
microlensing
events in real-time via frame subtraction. The improvement
in
angular resolution and photometric accuracy available from HST will
allow
us to 1} confirm that the detected flux excursions arise from LMC
source
stars rather than extended objects {such as for background
supernovae
or AGN}, and 2} obtain reliable baseline flux measurements
for
the objects in their unlensed state. The latter measurement is
important
to resolve degeneracies between the event timescale and
baseline
flux, which will yield a tighter constraint on the microlensing
optical
depth.
WFPC2
11024
WFPC2
CYCLE 15 INTERNAL MONITOR
This
calibration proposal is the Cycle 15 routine internal monitor for
WFPC2,
to be run weekly to monitor the health of the cameras. A variety
of
internal exposures are obtained in order to provide a monitor of the
integrity
of the CCD camera electronics in both bays {both gain 7 and
gain
15 -- to test stability of gains and bias levels}, a test for
quantum
efficiency in the CCDs, and a monitor for possible buildup of
contaminants
on the CCD windows. These also provide raw data for
generating
annual super-bias reference files for the calibration
pipeline.
FGS
11212
Filling
the Period Gap for Massive Binaries
The
current census of binaries among the massive O-type stars is
seriously
incomplete for systems in the period range from years to
millennia
because the radial velocity variations are too small and the
angular
separations too close for easy detection. Here we propose to
discover
binaries in this observational gap through a Faint Guidance
Sensor
SNAP survey of relatively bright targets listed in the Galactic O
Star
Catalog. Our primary goal is to determine the binary frequency
among
those in the cluster/association, field, and runaway groups. The
results
will help us assess the role of binaries in massive star
formation
and in the processes that lead to the ejection of massive
stars
from their natal clusters. The program will also lead to the
identification
of new, close binaries that will be targets of long term
spectroscopic
and high angular resolution observations to determine
their
masses and distances. The results will also be important for the
interpretation
of the spectra of suspected and newly identified binary
and
multiple systems.
NIC1/NIC2
11155
Dust
Grain Evolution in Herbig Ae Stars: NICMOS Coronagraphic Imaging
and
Polarimetry
We propose
to take advantage of the sensitive coronagraphic capabilities
of
NICMOS to obtain multiwavelength coronagraphic imaging and
polarimetry
of primordial dust disks around young intermediate-mass
stars
{Herbig Ae stars}, in order to advance our understanding of how
dust
grains are assembled into larger bodies. Because the polarization
of
scattered light is strongly dependent on scattering particle size and
composition,
coronagraphic imaging polarimetry with NICMOS provides a
uniquely
powerful tool for measuring grain properties in spatially
resolved
circumstellar disks. It is widely believed that planets form
via
the gradual accretion of planetesimals in gas-rich, dusty
circumstellar
disks, but the connection between this suspected process
and
the circumstellar disks that we can now observe around other stars
remains
very uncertain. Our proposed observations, together with
powerful
3-D radiative transfer codes, will enable us to quantitatively
determine
dust grain properties as a function of location within disks,
and
thus to test whether dust grains around young stars are in fact
growing
in size during the putative planet-formation epoch. HST imaging
polarimetry
of Herbig Ae stars will complement and extend existing
polarimetric
studies of disks around lower-mass T Tauri stars and debris
disks
around older main-sequence stars. When combined with these
previous
studies, the proposed research will help us establish the
influence
of stellar mass on the growth of dust grains into larger
planetesimals,
and ultimately to planets. Our results will also let us
calibrate
models of the thermal emission from these disks, a critical
need
for validating the properties of more distant disks inferred on the
basis
of spectral information alone.
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
11219
Active
Galactic Nuclei in Nearby Galaxies: a New View of the Origin of
the
Radio-loud Radio- quiet Dichotomy?
Using
archival HST and Chandra observations of 34 nearby early-type
galaxies
{drawn from a complete radio selected sample} we have found
evidence
that the radio-loud/radio-quiet dichotomy is directly connected
to
the structure of the inner regions of their host galaxies in the
following
sense: [1] Radio-loud AGN are associated with galaxies with
shallow
cores in their light profiles [2] Radio-quiet AGN are only
hosted
by galaxies with steep cusps. Since the brightness profile is
determined
by the galaxy's evolution, through its merger history, our
results
suggest that the same process sets the AGN flavour. This
provides
us with a novel tool to explore the co-evolution of galaxies
and
supermassive black holes, and it opens a new path to understand the
origin
of the radio-loud/radio-quiet AGN dichotomy. Currently our
analysis
is statistically incomplete as the brightness profile is not
available
for 82 of the 116 targets. Most galaxies were not observed
with
HST, while in some cases the study is obstructed by the presence of
dust
features. We here propose to perform an infrared NICMOS snapshot
survey
of these 82 galaxies. This will enable us to i} test the reality
of
the dichotomic behaviour in a substantially larger sample; ii} extend
the
comparison between radio-loud and radio-quiet AGN to a larger range
of
luminosities.
WFPC2
11070
WFPC2
CYCLE 15 Standard Darks - part II
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
11113
Binaries
in the Kuiper Belt: Probes of Solar System Formation and
Evolution
The
discovery of binaries in the Kuiper Belt and related small body
populations
is powering a revolutionary step forward in the study of
this
remote region. Three quarters of the known binaries in the Kuiper
Belt
have been discovered with HST, most by our snapshot surveys. The
statistics
derived from this work are beginning to yield surprising and
unexpected
results. We have found a strong concentration of binaries
among
low-inclination Classicals, a possible size cutoff to binaries
among
the Centaurs, an apparent preference for nearly equal mass
binaries,
and a strong increase in the number of binaries at small
separations.
We propose to continue this successful program in Cycle 16;
we
expect to discover at least 13 new binary systems, targeted to
subgroups
where these discoveries can have the greatest impact.
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
11227
The
Orbital Period for an Ultraluminous X-ray Source in NGC1313
The
ultraluminous X-ray sources {ULXs} are extragalactic point sources
with
luminosities that exceed the Eddington luminosity for conventional
stellar-mass
black holes by factors of 10 - 100. It has been hotly
debated
whether the ULXs are just common stellar-mass black hole sources
with
beamed emission or whether they are sub-Eddington sources that are
powered
by the long-sought intermediate mass black holes {IMBH}. To
firmly
decide this question, one must obtain dynamical mass measurements
through
photometric and spectroscopic monitoring of the secondaries of
these
system. The crucial first step is to establish the orbital period
of
a ULX, and arguably the best way to achieve this goal is by
monitoring
its ellipsoidal light curve. The extreme ULX NGC1313 X-2
provides
an outstanding target for an orbital period determination
because
its relatively bright optical counterpart {V = 23.5} showed a
15%
variation between two HST observations separated by three months.
This
level of variability is consistent with that expected for a tidally
distorted
secondary star. Here we propose a set of 20 imaging
observations
with HST/WFPC2 to define the orbital period. This would be
the
first photometric measurement of the orbital period of a ULX binary.
Subsequently,
we will propose to obtain spectroscopic observations to
obtain
its radial velocity amplitude and thereby a dynamical estimate of
its
mass.
WFPC2
11342
X-ray
Jets Activity in the Symbiotic System CH Cyg
We
propose follow up Chandra/HST/VLA observations of the recently
discovered
X-ray jets in the nearby symbiotic system CH Cyg. CH Cyg is
only
the second symbiotic systems with jet activity detected at X-ray
wavelengths.
Symbiotic systems are fascinating accreting binaries with a
key
evolutionary importance since they are potential progenitors of
bipolar
PN and SN type
Chandra
and VLA imaging, will provide the closest view of the region
where
jets form and interact with the surrounding material. The
observations
will provide a key information on the spatial, spectral and
temporal
characteristics of the jets, crucial inputs and quantitative
constraints
to models of non-relativistic jets.
WFPC2
11553
HST
Imaging of the Luminous Transient in NGC 300
A
luminous optical transient discovered in the nearby (~2.2 Mpc)
Sculptor
Group spiral NGC 300 in May 2008 appears to be a new member of
the
V838 Monocerotis class of stars that expand in a few weeks to become
red
supergiants. Spectroscopic observations show that the NGC 300 OT is
categorically
not a classical nova, supernova, or luminous blue
variable.
At an absolute magnitude of -12.5, it is by far the brightest
star
at present in NGC 300, but if it follows the pattern of V838 Mon
and
the similar object M31 RV, it will fade away rapidly in about 3
months.
Before
it fades, we propose to obtain WFPC2 images in order to locate
the
position of the object to within a few milliarcsec. This will allow
us
to identify the progenitor object, based on a superb set of
pre-outburst
ACS and WFPC2 images of NGC 300 available in the archive.
We
also propose a second observation in September 2008, in order to
search
for emergence of a light echo similar to the spectacular one that
surrounds
V838 Mon. If a light echo does appear, follow-up ACS
polarimetry
after SM4 offers the possibility of a direct geometric
distance
determination, allowing a fundamental calibration of the rich
variety
of standard candles that exist in NGC 300 (Cepheids, red-giant
tip,
planetary nebulae, etc.).
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11332
- GSACQ(1,2,2) failed, scan step limit exceeded on FGS 1
GSACQ(1,2,2) at 162/05:23:04 failed due to scan step limit
exceeded on
FGS 1. Vehicle was LOS at time of failure, #44 commands did not
update
from their values prior to LOS. QF1SSLEX, QSTOPF, QSTEPEXC and
QSTOP
flags were set at AOS, no 486 ESB messages were received,
REACQ(1,2,2) at 06:58:55 was successful.
Observations affected: NICMOS 11, WFPC 74 to 76, proposal 11142.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
08
07
FGS
REacq
07
07
OBAD
with Maneuver
15
15
SIGNIFICANT
EVENTS: (None)