Notice: For the foreseeable future, the daily reports may
contain
apparent discrepancies between some proposal descriptions
and the listed
instrument usage. This is due to the conversion of
previously approved
ACS WFC or HRC observations into WFPC2, or NICMOS
observations
subsequent to the loss of ACS CCD science capability in
late January.
HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4353
PERIOD COVERED: UT May 01, 2007 (DOY 121)
OBSERVATIONS SCHEDULED
WFPC2 10468
Jupiter's Upper Stratospheric Hazes Probed with Ganymede
I propose to observe a disappearance of Ganymede behind
the dark limb of
Jupiter with five filters of the ACS/HRC camera. Two
exposures in each
filter can be taken during such an event. The images will
provide the
spectral variation of the altitude of the apparent limb of
Jupiter. The
altitude of the apparent limb is dependent on the presence
of hazes in
Jupiter's stratosphere. Hazes of vertical optical depths below
0.001
could be detected with these observations, providing an
extremely
sensitive probe of high hazes. The observations probe
altitudes levels
near the 1-mb pressure level, for which we have very
limited data. The
creation of aerosols, their growth, and their transport by
winds is
currently a mostly theoretical study. It would
significantly benefit
from constraints derived from the proposed observations.
ACS/HRC is the
only instrument capable of the required spatial resolution
in the
ultraviolet. Furthermore, a favorable geometry of
Ganymede's orbit
occurs only once every six years. This proposal achieves
unique results
with a minimum of HST time.
WFPC2 10832
Solving the microlensing puzzle: An HST high-resolution
imaging approach
We propose to use the HST Advanced Camera for Surveys High
Resolution
Channel to obtain high resolution imaging data for 10
bona-fide LMC
microlensing events seen in the original MACHO survey. The
purpose of
this survey will be to assess whether or not the lens and
source stars
have separated enough to be resolved since the original
microlensing
event took place - about a decade has passed since the
original MACHO
survey and the HST WFPC2 follow-up observations of the
microlensing
events. If the components of the lensing event are
resolved, we will
determine the apparent magnitude and color of both the
lens and the
source stars. These data, in combination with Spitzer/IRAC
data and
Magellan near-IR JHK data, will be used to ascertain the
basic
properties of the lens stars. With the majority of the
microlensing
events in the original MACHO survey observed at the
highest spatial
resolution currently possible, we will be able to draw
important
conclusions as to what fraction of these events have
lenses which belong
to some population of dwarf stars in the disk and what
fraction must be
due to lenses in the halo or beyond. These data will
greatly increase
our understanding of the structure of the Galaxy by
characterizing the
stellar population responsible for the gravitational
microlensing.
WFPC2 10896
An Efficient ACS Coronagraphic Survey for Debris Disks
around Nearby
Stars
We propose to finish our Cycle 11 optical survey for
nearby debris disks
using the ACS/HRC coronagraph. Out of 43 orbits originally
proposed for
the survey, 23 orbits were allocated, leading to a survey
of 22 stars,
from which two new debris disks were imaged for the first
time. Our
analysis of the initial survey gives an empirical estimate
for the
detection rate of debris disks relative to heliocentric
distance and
dust optical depth. Our target list for Cycle 15 is now
optimized to
yield more frequent disk detections. Likewise our
observing strategy is
improved to maximize sensitivity per telescope orbit
allocated.
Therefore we present the most efficient survey possible.
The scientific
motivation is to obtain scattered light images of
previously unresolved
debris disks to determine their viewing geometry and
physical
architecture, both of which may characterize the underlying
planetary
system. We choose 25 debris disk targets for which we
predict a
detection rate of 25% ? 5%. Four targets have extrasolar
planets from
which the viewing geometry revealed by a disk detection
will resolve the
v sin{i} ambiguity in the planet masses. These targets
present the
remarkable opportunity of finally seeing a debris disk in
system with
known planets.
NIC1/NIC2/NIC3 8794
NICMOS Post-SAA calibration - CR Persistence Part 5
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.
NIC3 10792
Quasars at Redshift z=6 and Early Star Formation History
We propose to observe four high-redshift quasars {z=6} in
the NIR in
order to estimate relative Fe/Mg abundances and the central
black hole
mass. The results of this study will critically constrain
models of
joint quasar and galaxy formation, early star formation,
and the growth
of supermassive black holes. Different time scales and
yields for
alpha-elements {like O or Mg} and for iron result into an
iron
enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the
well-known
complexity of the FeII emission line spectrum, the ratio
iron/alpha -
element is a potentially useful cosmological clock. The
central black
hole mass will be estimated based on a recently revised
back hole mass -
luminosity relationship. The time delay of the iron
enrichment and the
time required to form a supermassive black hole {logM>8
Msol, tau
~0.5Gyr} as evidenced by quasar activity will be used to
date the
beginning of the first intense star formation, marking the
formation of
the first massive galaxies that host luminous quasars, and
to constrain
the epoch when supermassive black holes start to grow by
accretion.
WFPC2 10845
HUNTING FOR OPTICAL COMPANIONS TO BINARY MILLISECOND
PULSARS IN TERZAN 5
AND NGC6266
We propose deep WFPC2 and NICMOS observations to search
for optical
companions to binary millisecond pulsar {MSPs} in two
Globular Clusters
{GCs}: Terzan 5 and NGC6266. Terzan 5 has the largest MSP
population of
any GC: 33 MSP {17 in binary systems} have been discovered
up to now in
this stellar system. NGC6266 ranks fifth among the GC for
wealth of MSPs
but it is the only one in which all the {six} detected
MSPs are in
binary systems. Only 5 optical counterparts to binary MSP
companions are
known in GCs {two of them have been discovered by our
group}: hence even
the addition of a few new identifications are crucial to
investigate the
variety of processes occurring in binary MSPs in dense
environment. The
observations proposed here would easily double/triple the
existing
sample of known MSP companions, allowing the first
meaningful study of
the phenomena which drive the formation and evolution of
these exotic
systems. Moreover, since most of binary MSP in GC are
formed via stellar
interactions in the high density regions of the cluster,
the
determination of the nature of the companion and the
incidence of this
collisionally induced population have a significant impact
on our
knowledge of the cluster dynamics. Even more interesting,
the study of
the optical companions to NSs in a GC allows to derive
tighter
constraints {than those obtainable for NS binaries in the
galactic
field} on the properties {mass, orbital inclination and so
on} of the
compation star. This has, in turn, an intrisic importance
for
fundamental physics since it offers the opportunity of
measuring the
mass of the NS and hence to put constraints to the
equation of state of
matter at nuclear equilibrium density.
WFPC2 10890
Morphologies of the Most Extreme High-Redshift
Mid-IR-Luminous Galaxies
The formative phase of the most massive galaxies may be
extremely
luminous, characterized by intense star- and
AGN-formation. Till now,
few such galaxies have been unambiguously identified at
high redshift,
restricting us to the study of low-redshift ultraluminous
infrared
galaxies as possible analogs. We have recently discovered
a sample of
objects which may indeed represent this early phase in
galaxy formation,
and are undertaking an extensive multiwavelength study of
this
population. These objects are bright at mid-IR wavelengths
{F[24um]>0.8mJy}, but deep ground based imaging
suggests extremely faint
{and in some cases extended} optical counterparts
{R~24-27}. Deep K-band
images show barely resolved galaxies. Mid-infrared
spectroscopy with
Spitzer/IRS reveals that they have redshifts z ~ 2-2.5,
suggesting
bolometric luminosities ~10^{13-14}Lsun! We propose to
obtain deep ACS
F814W and NIC2 F160W images of these sources and their
environs in order
to determine kpc-scale morphologies and surface photometry
for these
galaxies. The proposed observations will help us determine
whether these
extreme objects are merging systems, massive obscured
starbursts {with
obscuration on kpc scales!} or very reddened {locally
obscured} AGN
hosted by intrinsically low-luminosity galaxies.
WFPC2 11027
Visible Earth Flats
This proposal monitors flatfield stability. This proposal
obtains
sequences of Earth streak flats to construct high quality
flat fields
for the WFPC2 filter set. These flat fields will allow
mapping of the
OTA illumination pattern and will be used in conjuction
with previous
internal and external flats to generate new pipeline
superflats. These
Earth flats will complement the Earth flat data obtained
during cycles
4-14.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation
Anomaly
Monitor
Intflat observations will be taken to provide a linearity
check: the
linearity test consists of a series of intflats in F555W,
in each gain
and each shutter. A combination of intflats, visflats, and
earthflats
will be used to check the repeatability of filter wheel
motions.
{Intflat sequences tied to decons, visits 1-18 in prop
10363, have been
moved to the cycle 15 decon proposal xxxx for easier
scheduling.} Note:
long-exposure WFPC2 intflats must be scheduled during ACS
anneals to
prevent stray light from the WFPC2 lamps from
contaminating long ACS
external exposures.
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:
18054-0 - Preview KF Sun Vector Data via Telemetry Diags
18060-0 - MSS/Gyro1 KF Initialization Convergence Testing
for SMS 120
18061-0 - MSS KF Adding Gyro1 Convergence Testing for SMS
120
18064-0 - PCS KF OOT Support, 121/18:20z
18065-0 - PCS KF OOT Support, 121/19:49z
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
13
13
FGS REacq
02
02
OBAD with Maneuver
28
28
SIGNIFICANT EVENTS:
Evaluation of Universal Kalman Filter performance
continued. Multiple
text segments were executed, all of them successfully.
Details follow.
Background Kalman Filter Operations Day 121:
The Kalman Filter (KF) was restarted on 120/14:35:30 after
being
halted on 116/21:00 for the Clock Roll-over.
The KF was halted at 121/11:22 (OR 18062-0) during orbit
day and during a
T2G guiding interval. The filter was restarted at
121/11:25 during
orbit day and during a fast changing B-field while
inertially
fixed. The filter was activated with only the MSS
enabled.
All UKF parameters showed nominal operation. The
test was an MSS
Initialization Test Case with the vehicle inertially fixed
during a fast
changing B-field (M_0_INF, Test #3). The MSS/CSS
default KF
configuration was restored at 121/12:13.
The Gyro1 sensor input was added to the KF at 121/15:10
(OR 18059-1)
during orbit day with no vehicle slew and during a T2G
guiding
interval. The filter was running with the MSS and
CSS sensor inputs
enabled and converged. All UKF parameters showed
nominal
operation. The test was an MSS/CSS/Gyro1 test case
with the Gyro1
sensor input removed at 121/16:30 with the filter
running. The
Gyro1 input was removed during an M2G guiding interval,
during orbit day,
during a vehicle maneuver and during a slow changing
B-field (MC_G1_HVS,
Test #32). The response to the removal of the gyro
input was
nominal and the filter remained converged. The
removal of the gyro
input restored the default MSS/CSS configuration of the
filter.
The KF was halted at 121/18:10 (OR 18060-0) during orbit
day and during
an M2G guiding interval. The filter was restarted at
121/18:21
during orbit day and during a slow changing B-field.
The filter was
activated with the MSS and Gyro1 sensor inputs
enabled. All UKF
parameters showed nominal operation. The test was an
MSS/Gyro1
Initialization test case during a vehicle slew, during a
slow changing
B-field (M_G1_IVS, Test #12). The Gyro1 sensor input
was removed at
121/18:34, however the CSS sensor input was intentionally
left disabled
to minimize the configuration changes needed for the next
test at 19:57
and because the originally scheduled TDRSS service to
execute the
reconfiguration was deleted.
The Gyro1 sensor input was added to the KF at 121/19:57
(OR 18061-0)
during orbit day, during a vehicle slew, during an M2G
guiding interval
and during a slow changing B-field. The filter was
running with
only the MSS sensor input enabled and converged. All
UKF parameters
showed nominal operation after the addition of the gyro
sensor input
enabling. The test was an MSS/Gyro1 test case with
the Gyro1 sensor
input added with the filter enabled and converged
(M_G1_RVS, Test
#20). The CSS sensor input was re-enabled, the Gyro1
sensor input
removed and the filter restarted during a T2G guiding
interval and during
orbit night at 121/20:15. This reconfiguration
restored the default
MSS/CSS configuration of the filter.