HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT #4904
PERIOD
COVERED: 5am August 6 - 5am August 7, 2009 (DOY 218/09:00z-219/09:00z)
OBSERVATIONS
SCHEDULED
ACS
11465
ACS
CCD Monitoring and Calibration for WFC3
This
program is a smaller version of our routine CCD monitoring program,
designed
to run throughout SMOV, after which our regular Cycle 17 CAL
proposal
will begin. This program obtains the bias and dark frames
needed
to generate reference files for calibrating science data, and
allows
us to monitor detector noise and the growth of hot pixels.
ACS/WFC3
11564
Optical
and Ultraviolet Photometry of Isolated Neutron Stars
We
propose ultraviolet and B-band observations of 5 nearby, thermally
emitting
neutron stars. These data will measure the Rayleigh-Jeans tails
of
their spectra, providing a vital complement to X-ray spectroscopy and
helping
to constrain atmospheric models, working toward the ultimate
goal
of unraveling the physics of neutron stars. With these data we will
have
good-quality optical and UV data for the full sample of these
objects,
allowing detailed comparisons between them. Finally, the data
should
allow us to measure proper motions for one or two objects, and
will
serve as the reference data for the remaining objects; such proper
motions
allow ages to be determined for these objects by tracing them
back
to likely birth locations.
COS
11487
COS
FUV Internal/External Wavelength Scales
Observe
external radial velocity standard targets in TIME-TAG
(FLASH=YES)
mode with all grating and central wavelength combinations.
The
purpose is to obtain zero-point offsets for the wavelength scale
(internal
wavecal lamp scale to external standard wavelength scale) and
PSA
dispersion relations for all central wavelengths.
Following
this determination, adjustments of the nominal science target
spectral
range for each grating and central wavelength combination will
be
made via SMS patchable constant for nominal OSM1 positions
corresponding
to each central wavelength. Subsequent to this
modification
of the wavelength scale (and its verification via analysis
of
COS30 - program 11488), FUV science-related operations and
wavelength-dependent
EROs can commence.
COS
11488
Internal
FUV Wavelength Verification
This
program will be executed after the uplink of the OSM1 position
updates
derived from the determination of the wavelength-scale zero
points
and desired spectral ranges for each grating in activity COS29
(program
11487 - COS FUV Internal/External Wavelength Scales). This
program
will verify that the operational spectral ranges for each
grating,
central wavelength, and FP-POS are those desired. Subsequent to
a
successful verification, COS FUV ERO observations that require
accurate
wavelength scales (if any) and FUV science can be enabled. An
internal
wavelength calibration spectrum using the default PtNe lamp
(lamp
1) with each FUV grating at each central wavelength setting and
each
FP-POS position will be obtained for the verification. Additional
exposures
and waits between certain exposures will be required to avoid
-
and to evaluate - mechanism drifts.
COS
11492
FUV
Sensitivity
DESCRIPTION:
This activity confirms COS sensitivity versus wavelength
over
the entire observable spectrum for all FUV gratings and central
wavelength
settings. Obtain quick look sensitivity visit early in SMOV.
Later,
after wavelength calibration is verified, perform a
precise-centering
acquisition and observe an appropriate HST flux
standard
star (chosen from the HST prime standard and FASTEX lists) with
the
PSA. (A limited BOA characterization is obtained in Visit 13 using
primary
standard GD153.) No off aperture-center observations are
performed
in this activity (see COS32, program 11490, for off-center
characterizations).
Spectra will be obtained to meet a Poisson S/N
criterion
of ~30 per sensitivity extraction bin or higher; substantially
higher
S/N characterization will be utilized in routine Cycle 17
calibration.
FGS
11704
The
Ages of Globular Clusters and the Population II Distance Scale
Globular
clusters are the oldest objects in the universe whose age can
be
accurately determined. The dominant error in globular cluster age
determinations
is the uncertain Population II distance scale. We propose
to
use FGS 1r to obtain parallaxes with an accuracy of 0.2
milliarcsecond
for 9 main sequence stars with [Fe/H] < -1.5. This will
determine
the absolute magnitude of these stars with accuracies of 0.04
to
0.06mag. This data will be used to determine the distance to 24
metal-poor
globular clusters using main sequence fitting. These
distances
(with errors of 0.05 mag) will be used to determine the ages
of
globular clusters using the luminosity of the subgiant branch as an
age
indicator. This will yield absolute ages with an accuracy 5%, about
a
factor of two improvement over current estimates. Coupled with
existing
parallaxes for more metal-rich stars, we will be able to
accurately
determine the age for globular clusters over a wide range of
metallicities
in order to study the early formation history of the Milky
Way
and provide an independent estimate of the age of the universe.
The
Hipparcos database contains only 1 star with [Fe/H] < -1.4 and an
absolute
magnitude error less than 0.18 mag which is suitable for use in
main
sequence fitting. Previous attempts at main sequence fitting to
metal-poor
globular clusters have had to rely on theoretical
calibrations
of the color of the main sequence. Our HST parallax program
will
remove this source of possible systematic error and yield distances
to
metal-poor globular clusters which are significantly more accurate
than
possible with the current parallax data. The HST parallax data will
have
errors which are 10 times smaller than the current parallax data.
Using
the HST parallaxes, we will obtain main sequence fitting distances
to
11 globular clusters which contain over 500 RR Lyrae stars. This will
allow
us to calibrate the absolute magnitude of RR Lyrae stars, a
commonly
used Population II distance indicator.
STIS
11403
MAMA
Spectroscopic Throughputs
This
activity sets new baseline post-SM4 sensitivity/throughput
measurements
for all the STIS/MAMA spectroscopic modes, and establishes
if
there changes with respect to performance prior to the LVPS failure.
It
also checks the NUV focus of STIS and its dependence on wavelength.
STIS/CCD
11844
CCD
Dark Monitor Part 1
Monitor
the darks for the STIS CCD.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
Monitor
the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and
1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution
of hot columns.
STIS20
11402
STIS-20
NUV MAMA Dark Monitor
The
STIS NUV-MAMA dark current is dominated by a phosphorescent glow
from
the detector window. Meta-stable states in this window are
populated
by cosmic ray impacts, which, days later, can be thermally
excited
to an unstable state from which they decay, emitting a UV
photon.
The equilibrium population of these meta-stable states is larger
at
lower temperatures; so warming up the detector from its cold safing
will
lead to a large, but temporary, increase in the dark current.
To
monitor the decay of this glow, and to determine the equilibrium dark
current
for Cycle 17, four 1380s NUV-MAMA ACCUM mode darks should be
taken
each week during the SMOV period. Once the observed dark current
has
reached an approximate equilibrium with the mean detector
temperature,
the frequency of this monitor can be reduced to one pair of
darks
per week.
WFC3
11447
WFC3
IR Dark Current, Readnoise, and Background
This
proposal obtains full-frame, four-amp readout images.
Un-illuminated
internals are taken at regularly spaced intervals
throughout
SMOV in order to assess and monitor readnoise and dark
current
(of both light-sensitive pixels and reference pixels), and bad
(warm,
hot, dead, variable) pixels. In addition, externals aimed at
fields
with sparse stellar density are taken to measure diffuse
background
light.
This
program corresponds to WFC3-34.
WFC3
11552
Characterization
of the WFC3 IR Grisms
Image
displacement, spectral trace and dispersion, and throughput of the
IR
G102 and G141 grisms will be verified. The HST flux standard GD 153
will
be observed in a 5-point pattern in the IR field of view, which
will
provide image displacement, spectral trace, and throughput
measurements
as a function of location within the FOV. Similarly, the
planetary
nebula PN HB12 will be observed in a 9-point pattern in the IR
field
of view, which will provide dispersion measurements as a function
of
FOV position.
WFC3
11808
WFC3
UVIS Bowtie Monitor
The
UVIS detector was observed during ground testing to occasionally
exhibit
flat field and dark variations with a bowtie pattern. These
variations
are most significant as ~1% flat field (gain) variations
across
the field of view. It is believed that this represents a state or
condition
into which the detector can transition for reasons and under
circumstances
which are not currently understood. It is also very
unlikely
that most science observations will determine the state (bowtie
or
no-bowtie) of the detector. Ground test data indicates that this
state
is long lived (many hours to ~one day). Hysteresis or memory of
past
light exposure is also associated with this state.
Recent
evidence suggests that exposing the detector to ~200k to 500k
electrons
may quench this state. This proposal obtains an internal flat
field
sequence of three exposures: one at 10x full well with two at 0.5x
full
well immediately before and after. Each exposure is 3x3 binned to
reduce
the data volume required.
These
visits should be scheduled 2x per day until further direction is
provided.
WFC3/UVI
11580
Watching
Young Planetary Nebulae Grow: The Movie
The
development of magneto-hydro gas dynamical models is the key to the
understanding
of both the physics (processes) and astronomy (initial
conditions)
of astrophysical nebulae of all sorts. The models are
reaching
their highest degree of accuracy when applied to and compared
against
pre Planetary Nebulae (pPNe) thanks to the simplicity, relative
lack
of extinction, and the detail of the imaging and kinematic data
that
have bcome available for these objects. The primary barrier to
progress
is inadequate kinematic data of pPNe against which the
predictions
models can be tested. Unlike PNe, pPNe do not emit emission
lines
for detailed Doppler measurements. Therefore it is essential to
find
another way to monitor the morphological evolution.
Only
HST can uncover the dynamics of the growth patterns by subtracting
multi-epoch
images spanning a decade or more. We have selected four pPNe
with
highly collimated outflows in different evolutionary stages for
which
high-quality first epoch images were obtained from 1996 to 2002.
All
of them display regularly shaped thin rims, sharp edges, and
symmetric
pairs of knots or bowshocks that are ideal for our purposes.
We
will closely mimic many of the earlier exposures using ACS and to
monitor
changes in structures. The morphology and its evolution will be
compared
to 3-D MHD models with adaptive grids in order to build a far
clearer
picture of the nuclear geometry which shaped the outflows and
constrained
their propagation to the present. We shall also obtain R, J,
and
H images for use with a 3-D dust radiative transfer code LELUYA to
model
the dust distribution deep into the nuclear zones.
WFC3/UVI
11628
Globular
Cluster Candidates for Hosting a Central Black Hole
We
are continuing our study of the dynamical properties of globular
clusters
and we propose to obtain surface brightness profiles for high
concentration
clusters. Our results to date show that the distribution
of
central surface brightness slopes do not conform to standard models.
This
has important implications for how they form and evolve, and
suggest
the possible presence of central intermediate-mass black holes.
From
our previous archival proposals (AR-9542 and AR- 10315), we find
that
many high concentration globular clusters do not have flat cores or
steep
central cusps, instead they show weak cusps. Numerical simulations
suggest
that clusters with weak cusps may harbor intermediate-mass black
holes
and we have one confirmation of this connection with omega
Centauri.
This cluster shows a shallow cusp in its surface brightness
profile,
while kinematical measurements suggest the presence of a black
hole
in its center. Our goal is to extend these studies to a sample
containing
85% of the Galactic globular clusters with concentrations
higher
than 1.7 and look for objects departing from isothermal behavior.
The
ACS globular cluster survey (GO-10775) provides enough objects to
have
an excellent coverage of a wide range of galactic clusters, but it
contains
only a couple of the ones with high concentration. The proposed
sample
consists of clusters whose light profile can only be adequately
measured
from space-based imaging. This would take us close to
completeness
for the high concentration cases and therefore provide a
more
complete list of candidates for containing a central black hole.
The
dataset will also be combined with our existing kinematic
measurements
and enhanced with future kinematic studies to perform
detailed
dynamical modeling.
WFC3/UVI/IR
11557
The
Nature of Low-Ionization BAL QSOs
The
rare subclass of optically-selected QSOs known as low-ionization
broad
absorption line (LoBAL) QSOs show signs of high-velocity gas
outflows
and reddened continua indicative of dust obscuration. Recent
studies
show that galaxies hosting LoBAL QSOs tend to be ultraluminous
infrared
systems that are undergoing mergers, and that have dominant
young
(< 100 Myr) stellar populations. Such studies support the idea
that
LoBAL QSOs represent a short- lived phase early in the life of
QSOs,
when powerful AGN-driven winds are blowing away the dust and gas
surrounding
the QSO. If so, understanding LoBALs would be critical in
the
study of phenomena regulating black hole and galaxy evolution, such
as
AGN feedback and the early stages of nuclear accretion. These
results,
however, come from very small samples that may have serious
selection
biases. We are therefore taking a more aggressive approach by
conducting
a systematic multiwavelength study of a volume limited sample
of
LoBAL QSOs at 0.5 < z < 0.6 drawn from SDSS. We propose to image
their
host galaxies in two bands using WFC3/UVIS and WFC3/IR to study
the
morphologies for signs of recent tidal interactions and to map their
interaction
and star forming histories. We will thus determine whether
LoBAL
QSOs are truly exclusively found in young merging systems that are
likely
to be in the early stages of nuclear accretion.
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:
18674-0
- Restore COS FUV HV Nom values @ 218/1414z
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
11
11
FGS
REAcq
06
06
OBAD
with Maneuver
11
11
SIGNIFICANT
EVENTS: (None)