HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5171
PERIOD
COVERED: 5am August 30 - 5am August 31, 2010 (DOY 242/09:00z-243/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12367
- GSAcq(2,1,1) at 242/18:55:15z failed to gyro control due to search radius
limit
exceeded on FGS2.
Observations affected WFC3 17-18 Proposal ID#11644
12369
- GSAcq(2,1,1) at 243/06:33:18z and REAcq(1,2,1) at 243/07:47:55z acquired Fine
Lock
Backup on FGS 1 Due to Search Radius Limit Exceeded on FGS 2.
Observations possibly affected WFC3 32-25 Proposal ID#11840 and WFC3 36
Proposal ID#11929.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES:
2072-0
- Battery Pressure and FSW SOC Ground Limit Update
SCHEDULED SUCCESSFUL
FGS
GSAcq 8 7
FGS
REAcq 8 8
OBAD
with Maneuver 6 6
SIGNIFICANT
EVENTS:
Flash
Report:
At
approximately DOY 2010/242 16:52 GMT (12:52pm local), the EPS FSW SOC
parameters
and Battery Pressure (PSI) safing test limits were modified
by
15 AH to accommodate the increase in battery capacity.
OBSERVATIONS
SCHEDULED:
ACS/WFC
11996
CCD
Daily Monitor (Part 3)
This
program comprises basic tests for measuring the read noise and dark
current
of the ACS WFC and for tracking the growth of hot pixels. The
recorded
frames are used to create bias and dark reference images for
science
data reduction and calibration. This program will be executed
four
days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To
facilitate
scheduling, this program is split into three proposals. This
proposal
covers 308 orbits (19.25 weeks) from 21 June 2010 to 1 November
2010.
COS/FUV
11895
FUV
Detector Dark Monitor
Monitor
the FUV detector dark rate by taking long science exposures
without
illuminating the detector. The detector dark rate and spatial
distribution
of counts will be compared to pre-launch and SMOV data in
order
to verify the nominal operation of the detector. Variations of
count
rate as a function of orbital position will be analyzed to find
dependence
of dark rate on proximity to the SAA. Dependence of dark rate
as
function of time will also be tracked.
COS/FUV
11897
FUV
Spectroscopic Sensitivity Monitoring
The
purpose of this proposal is to monitor sensitivity in each FUV
grating
mode to detect any changes due to contamination or other causes.
COS/FUV/STIS/CCD/MA1
11592
Testing
the Origin(s) of the Highly Ionized High-Velocity Clouds: A
Survey
of Galactic Halo Stars at z>3 kpc
Cosmological
simulation predicts that highly ionized gas plays an
important
role in the formation and evolution of galaxies and their
interplay
with the intergalactic medium. The NASA HST and FUSE missions
have
revealed high-velocity CIV and OVI absorption along extragalactic
sightlines
through the Galactic halo. These highly ionized high-velocity
clouds
(HVCs) could cover 85% of the sky and have a detection rate
higher
than the HI HVCs. Two competing, equally exciting, theories may
explain
the origin of these highly ionized HVCs: 1) the "Galactic"
theory,
where the HVCs are the result of feedback processes and trace
the
disk-halo mass exchange, perhaps including the accretion of matter
condensing
from an extended corona; 2) the "Local Group" theory, where
they
are part of the local warm-hot intergalactic medium, representing
some
of the missing baryonic matter of the Universe. Only direct
distance
determinations can discriminate between these models. Our group
has
found that some of these highly ionized HVCs have a Galactic origin,
based
on STIS observations of one star at z<5.3 kpc. We propose an HST
FUV
spectral survey to search for and characterize the high velocity NV,
CIV,
and SiIV interstellar absorption toward 24 stars at much larger
distances
than any previous searches (4<d<21 kpc, 3<|z|<13 kpc). COS
will
provide atomic to highly ionized species (e.g.,OI, CII, CIV, SiIV)
that
can be observed at sufficient resolution (R~22, 000) to not only
detect
these highly ionized HVCs but also to model their properties and
understand
their physics and origins. This survey is only possible
because
of the high sensitivity of COS in the FUV spectral range.
COS/NUV
11894
NUV
Detector Dark Monitor
The
purpose of this proposal is to measure the NUV detector dark rate by
taking
long science exposures with no light on the detector. The
detector
dark rate and spatial distribution of counts will be compared
to
pre-launch and SMOV data in order to verify the nominal operation of
the
detector. Variations of count rate as a function of orbital position
will
be analyzed to find dependence of dark rate on proximity to the
SAA.
Dependence of dark rate as function of time will also be tracked.
COS/NUV
11896
NUV
Spectroscopic Sensitivity Monitoring
The
purpose of this proposal is to monitor sensitivity of each NUV
grating
mode to detect any changes due to contamination or other causes.
COS/NUV/FUV
12034
COS-GTO:
Brown Dwarf Activity Part 2
Based
on the Findings in our Cycle 17 program, we will focus on M-stars
in
Cycle 18.
S/C
11639
Catching
Accreting WDs Moving into Their Instability Strip(s)
Our
past HST studies of the temperatures of 9 accreting, pulsating white
dwarfs
in cataclysmic variables show that 3 are in the normal
instability
strip for single white dwarfs, but the other 6 are much
hotter
(15, 000-16, 500K). This dual strip has been proposed to be due
to
mass differences in the white dwarfs related to evolutionary history
and
driven by the ionization of different elements in their respective
driving
regions. In 2007, GW Lib (the brightest and best studied of the
6
hot accreting pulsators) and V455 And (the brightest and best studied
of
the 3 cool accreting pulsators) underwent rare large amplitude dwarf
nova
outbursts (known to heat the white dwarf) and their pulsations
disappeared.
We propose COS observations to: a) take advantage of the
unprecedented
opportunity to view the change in pulsation modes due to
cooling
of the white dwarf envelope and b) determine the masses of the
white
dwarfs to test the dual strip theory. In addition, a nova that had
its
outburst 22 yrs ago has begun non-radial pulsations as it returns to
quiescence.
We will use COS to determine its temperature in relation to
the
instability strip for the pulsating white dwarfs in dwarf novae.
STIS/CCD/MA
11668
Cosmo-chronometry
and Elemental Abundance Distribution of the Ancient
Star
HE1523-0901
We
propose to obtain near-UV HST/STIS spectroscopy of the extremely
metal-poor,
highly r-process-enhanced halo star HE 1523-0901, in order
to
produce the most complete abundance distribution of the heaviest
stable
elements, including platinum, osmium, and lead. These HST
abundance
data will then be used to estimate the initial abundances of
the
long-lived radioactive elements thorium and uranium, and by
comparison
with their observed abundances, enable an accurate age
determination
of this ancient star. The use of radioactive chronometers
in
stars provides an independent lower limit on the age of the Galaxy,
which
can be compared with alternative limits set by globular clusters
and
by analysis from WMAP. Our proposed observations of HE1523-0901 will
also
provide significant new information about the early chemical
history
of the Galaxy, specifically, the nature of the first generations
of
stars and the types of nucleosynthetic processes that occurred at the
onset
of Galactic chemical evolution.
STIS/CCD
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
STIS/CCD
11847
CCD
Bias Monitor-Part 2
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.
STIS/CCD
11853
Cycle
17 STIS CCD Imaging Flats
This
program periodically monitors the STIS CCD imaging mode flat fields
by
using the tungsten lamps.
STIS/CCD/FGS
11848
CCD
Read Noise Monitor
This
proposal measures the read noise of all the amplifiers (A, B, C, D)
on
the STIS CCD using pairs of bias frames. Full-frame and binned
observations
are made in both Gain 1 and Gain 4, with binning factors of
1x1,
1x2, 2x1, and 2x2. All exposures are internals. Pairs of visits are
scheduled
monthly for the first four months and then bi-monthly after
that.
WFC3/ACS/IR
11840
Identifying
the Host Galaxies for Optically Dark Gamma-Ray Bursts
We
propose to use the high spatial resolution of Chandra to obtain
precise
positions for a sample of Gamma-Ray Bursts (GRBs) with no
optical
afterglows, where the optical light is suppressed relative to
the
X-ray flux. These bursts are likely to be highly obscured and may
have
different environments from the optically bright GRBs. Our Chandra
observations
will (unlike Swift XRT positions) allow for the unique
identification
of a host galaxy. To locate these host galaxies we will
follow
up our Chandra positions with deep optical and IR observations
with
HST. The ultimate aim is to understand any differences between the
host
galaxies of optically dark and bright GRBs, and how these affect
the
use of GRBs as tracers of starformation and galaxy evolution at high
redshift.
WFC3/ACS/IR
11563
Galaxies
at z~7-10 in the Reionization Epoch: Luminosity Functions to
<0.2L*
from Deep IR Imaging of the HUDF and HUDF05 Fields
The
first generations of galaxies were assembled around redshifts
z~7-10+,
just 500-800 Myr after recombination, in the heart of the
reionization
of the universe. We know very little about galaxies in this
period.
Despite great effort with HST and other telescopes, less than
~15
galaxies have been reliably detected so far at z>7, contrasting with
the
~1000 galaxies detected to date at z~6, just 200-400 Myr later, near
the
end of the reionization epoch. WFC3 IR can dramatically change this
situation,
enabling derivation of the galaxy luminosity function and its
shape
at z~7-8 to well below L*, measurement of the UV luminosity
density
at z~7-8 and z~8-9, and estimates of the contribution of
galaxies
to reionization at these epochs, as well as characterization of
their
properties (sizes, structure, colors). A quantitative leap in our
understanding
of early galaxies, and the timescales of their buildup,
requires
a total sample of ~100 galaxies at z~7-8 to ~29 AB mag. We can
achieve
this with 192 WFC3 IR orbits on three disjoint fields
(minimizing
cosmic variance): the HUDF and the two nearby deep fields of
the
HUDF05. Our program uses three WFC3 IR filters, and leverages over
600
orbits of existing ACS data, to identify, with low contamination, a
large
sample of over 100 objects at z~7-8, a very useful sample of ~23
at
z~8-9, and limits at z~10. By careful placement of the WFC3 IR and
parallel
ACS pointings, we also enhance the optical ACS imaging on the
HUDF
and a HUDF05 field. We stress (1) the need to go deep, which is
paramount
to define L*, the shape, and the slope alpha of the luminosity
function
(LF) at these high redshifts; and (2) the far superior
performance
of our strategy, compared with the use of strong lensing
clusters,
in detecting significant samples of faint z~7-8 galaxies to
derive
their luminosity function and UV ionizing flux. Our recent z~7.4
NICMOS
results show that wide-area IR surveys, even of GOODS-like depth,
simply
do not reach faint enough at z~7-9 to meet the LF and UV flux
objectives.
In the spirit of the HDF and the HUDF, we will waive any
proprietary
period, and will also deliver the reduced data to STScI. The
proposed
data will provide a Legacy resource of great value for a wide
range
of archival science investigations of galaxies at redshifts z~2-
9.
The data are likely to remain the deepest IR/optical images until
JWST
is launched, and will provide sources for spectroscopic follow up
by
JWST, ALMA and EVLA.
WFC3/IR/S/C
11929
IR
Dark Current Monitor
Analyses
of ground test data showed that dark current signals are more
reliably
removed from science data using darks taken with the same
exposure
sequences as the science data, than with a single dark current
image
scaled by desired exposure time. Therefore, dark current images
must
be collected using all sample sequences that will be used in
science
observations. These observations will be used to monitor changes
in
the dark current of the WFC3-IR channel on a day-to-day basis, and to
build
calibration dark current ramps for each of the sample sequences to
be
used by Gos in Cycle 17. For each sample sequence/array size
combination,
a median ramp will be created and delivered to the
calibration
database system (CDBS).
WFC3/IR/S/C
12089
Persistence
- Part 2
The
IR detectors on WFC3, like other IR detectors, trap charge when
exposed
to sources near or above the full well of the detector diodes.
This
charge leaks out, producing detectable afterglow images for periods
which
can last for several hours, depending on the amount of over
exposure.
These visits, which consist of tungsten lamp exposures of
varying
durations followed by darks, are intended to provide a better
calibration
of persistence over the full area of the IR detector of
WFC3.
WFC3/UV
12091
WFC3/UVIS
Fringe Calibration - Part 2
Fringing
has been observed in flat fields of 12 narrowband filters (4
full-frame
and 3 quad spectral elements) longer than 600 nm, with
peak-to-peak
fringe amplitude variations ranging from 0.5% to 14.2%
(WFC3
ISR 2010-04). Two filters (F953N and F656N) will be tested in
program
11922, supporting 88 Cycle 17 GO exposures in these filters.
Here
we propose to observe globular cluster Omega Centauri (NGC 5139) in
the
other 10 filters affected by fringing, supporting 319 Cycle 17 GO
exposures
in these filters. By measuring the relative changes in
brightness
of stars at different positions on the detector, we will
determine
the local variations induced by the fringing pattern.
The
data will serve two purposes: characterize the effect of fringing on
photometry
of on-orbit data, and verify models used to correct for
fringing
effects. The models rely on Thermal Vacuum Test 3 (TV3) data
between
845-990 nm and NASA/GSFC Detector Characterization Laboratory
(DCL)
test data from 700-1060 nm. Only the F953N filter in program 11922
overlaps
with the test data wavelength range, making it difficult to
compare
the efficacy of fringe models. This program will expand the
on-orbit
fringing data so that we can compare models at 6 new
wavelengths
within the ground test data wavelength range, as well as 4
new
wavelengths not covered by the ground test data. Flight data in
these
4 filters can be corrected by extrapolating the model beyond the
wavelength
range of the test data used to create the model.
WFC3/UVIS
11657
The
Population of Compact Planetary Nebulae in the Galactic Disk
We
propose to secure narrow- and broad-band images of compact planetary
nebulae
(PNe) in the Galactic Disk to study the missing link of the
early
phases of post-AGB evolution. Ejected AGB envelopes become PNe
when
the gas is ionized. PNe expand, and, when large enough, can be
studied
in detail from the ground. In the interim, only the HST
capabilities
can resolve their size, morphology, and central stars. Our
proposed
observations will be the basis for a systematic study of the
onset
of morphology. Dust properties of the proposed targets will be
available
through approved Spitzer/IRS spectra, and so will the
abundances
of the alpha- elements. We will be able thus to explore the
interconnection
of morphology, dust grains, stellar evolution, and
populations.
The target selection is suitable to explore the nebular and
stellar
properties across the galactic disk, and to set constraints on
the
galactic evolutionary models through the analysis of metallicity and
population
gradients.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
WFC3/UVIS
11908
Cycle
17: UVIS Bowtie Monitor
Ground
testing revealed an intermittent hysteresis type effect in the
UVIS
detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially
found via an unexpected bowtie- shaped feature in flatfield
ratios,
subsequent lab tests on similar e2v devices have since shown
that
it is also present as simply an overall offset across the entire
CCD,
i.e., a QE offset without any discernable pattern. These lab tests
have
further revealed that overexposing the detector to count levels
several
times full well fills the traps and effectively neutralizes the
bowtie.
Each visit in this proposal acquires a set of three 3x3 binned
internal
flatfields: the first unsaturated image will be used to detect
any
bowtie, the second, highly exposed image will neutralize the bowtie
if
it is present, and the final image will allow for verification that
the
bowtie is gone.
WFC3/UVIS
11914
UVIS
Earth Flats
This
program is an experimental path finder for Cycle 18 calibration.
Visible-wavelength
flat fields will be obtained by observing the dark
side
of the Earth during periods of full moon illumination. The
observations
will consist of full-frame streaked WFC3 UVIS imagery: per
22-
min total exposure time in a single "dark-sky" orbit, we anticipate
collecting
7000 e/pix in F606W or 4500 e/pix in F814W. To achieve
Poisson
S/N > 100 per pixel, we require at least 2 orbits of F606W and 3
orbits
of F814W.
For
UVIS narrowband filters, exposures of 1 sec typically do not
saturate
on the sunlit Earth, so we will take sunlit Earth flats for
three
of the more-commonly used narrowband filters in Cycle 17 plus the
also-popular
long-wavelength quad filters, for which we get four filters
at
once.
Why
not use the Sunlit Earth for the wideband visible-light filters? It
is
too bright in the visible for WFC3 UVIS minimum exposure time of 0.5
sec.
Similarly, for NICMOS the sunlit-Earth is too bright which
saturates
the detector too quickly and/or induces abnormal behaviors
such
as super-shading (Gilmore 1998, NIC 098-011). In the narrowband
visible
and broadband near- UV its not too bright (predictions in Cox et
al.
1987 "Standard Astronomical Sources for HST: 6. Spatially Flat
Fields."
and observations in ACS Program 10050).
Other
possibilities? Cox et al.'s Section II.D addresses many other
possible
sources for flat fields, rejecting them for a variety of
reasons.
A remaining possibility would be the totally eclipsed moon.
Such
eclipses provide approximately 2 hours (1 HST orbit) of opportunity
per
year, so they are too rare to be generically useful. An advantage of
the
moon over the Earth is that the moon subtends less than 0.25 square
degree,
whereas the Earth subtends a steradian or more, so scattered
light
and light potentially leaking around the shutter presents
additional
problems for the Earth. Also, we're unsure if HST can point
180
deg from the Sun.
WFC3/UVIS/IR
11644
A
Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into
the
Formation of the Outer Solar System
The
eight planets overwhelmingly dominate the solar system by mass, but
their
small numbers, coupled with their stochastic pasts, make it
impossible
to construct a unique formation history from the dynamical or
compositional
characteristics of them alone. In contrast, the huge
numbers
of small bodies scattered throughout and even beyond the
planets,
while insignificant by mass, provide an almost unlimited number
of
probes of the statistical conditions, history, and interactions in
the
solar system. To date, attempts to understand the formation and
evolution
of the Kuiper Belt have largely been dynamical simulations
where
a hypothesized starting condition is evolved under the
gravitational
influence of the early giant planets and an attempt is
made
to reproduce the current observed populations. With little
compositional
information known for the real Kuiper Belt, the test
particles
in the simulation are free to have any formation location and
history
as long as they end at the correct point. Allowing compositional
information
to guide and constrain the formation, thermal, and
collisional
histories of these objects would add an entire new dimension
to
our understanding of the evolution of the outer solar system. While
ground
based compositional studies have hit their flux limits already
with
only a few objects sampled, we propose to exploit the new
capabilities
of WFC3 to perform the first ever large-scale
dynamical-compositional
study of Kuiper Belt Objects (KBOs) and their
progeny
to study the chemical, dynamical, and collisional history of the
region
of the giant planets. The sensitivity of the WFC3 observations
will
allow us to go up to two magnitudes deeper than our ground based
studies,
allowing us the capability of optimally selecting a target list
for
a large survey rather than simply taking the few objects that can be
measured,
as we have had to do to date. We have carefully constructed a
sample
of 120 objects which provides both overall breadth, for a general
understanding
of these objects, plus a large enough number of objects in
the
individual dynamical subclass to allow detailed comparison between
and
within these groups. These objects will likely define the core
Kuiper
Belt compositional sample for years to come. While we have many
specific
results anticipated to come from this survey, as with any
project
where the field is rich, our current knowledge level is low, and
a
new instrument suddenly appears which can exploit vastly larger
segments
of the population, the potential for discovery -- both
anticipated
and not -- is extraordinary.