HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5152
PERIOD
COVERED: 5am August 3 - 5am August 4, 2010 (DOY 215/09:00z-216/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
FOR
DOY 200
12346
- GSAcq(1,2,1) at 200/07:14:07z required three attempts to achieve
FL-DV on FGS1, receiving scan step limit exceeded twice. The
acquisition
was successful.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
6
6
FGS
REAcq
9
9
OBAD
with Maneuver 4
4
SIGNIFICANT
EVENTS: (None)
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.
ACS/WFC
12327
Calibration
of the ACS CTE at Low Signal Levels
The
empirical pixed-based CTE correction algorithm of Anderson & Bedin
(2010)
provides excellent results for ACS/WFC pixel signals above ~10
DN,
but it is not well calibrated for smaller signals because of the
lack
of uncontaminated "warm-pixel" trails in standard long-exposure
dark
frames. To improve the CTE model at signals below ~ 10 DN, short
dark
frames are needed to obtain a statistically useful sample of clean,
warm
pixel trails. This program obtains 9 dark frames for each of the
following
exposure times: 33 s, 100 s, and 339 s. These short darks and
the
1000 s darks obtained from the CCD Daily Monitor will sample warm
and
hot pixels over logarithmically increasing brightness.
ACS/WFC3
11882
CCD
Hot Pixel Annealing
This
program continues the monthly anneal that has taken place every
four
weeks for the last three cycles. We now obtain WFC biases and darks
before
and after the anneal in the same sequence as is done for the ACS
daily
monitor (now done 4 times per week). So the anneal observation
supplements
the monitor observation sets during the appropriate week.
Extended
Pixel Edge Response (EPER) and First Pixel Response (FPR) data
will
be obtained over a range of signal levels for the Wide Field
Channel
(WFC). This program emulates the ACS pre-flight ground
calibration
and post-launch SMOV testing (program 8948), so that results
from
each epoch can be directly compared. The High Resolution Channel
(HRC)
visits have been removed since it could not be repaired during
SM4.
This
program also assesses the read noise, bias structure, and amplifier
cross-talk
of ACS/WFC using the GAIN=1.4 A/D conversion setting. This
investigation
serves as a precursor to a more comprehensive study of WFC
performance
using GAIN=1.4.
COS/FUV
11625
Beyond
the Classical Paradigm of Stellar Winds: Investigating Clumping,
Rotation
and the Weak Wind Problem in SMC O Stars
SMC
O stars provide an unrivaled opportunity to probe star formation,
evolution,
and the feedback of massive stars in an environment similar
to
the epoch of the peak in star formation history. Two recent
breakthroughs
in the study of hot, massive stars have important
consequences
for understanding the chemical enrichment and buildup of
stellar
mass in the Universe. The first is the realization that rotation
plays
a major role in influencing the evolution of massive stars and
their
feedback on the surrounding environment. The second is a drastic
downward
revision of the mass loss rates of massive stars coming from an
improved
description of their winds. STIS spectroscopy of SMC O stars
combined
with state-of-the-art NLTE analyses has shed new light on these
two
topics. A majority of SMC O stars reveal CNO- cycle processed
material
brought at their surface by rotational mixing. Secondly, the
FUV
wind lines of early O stars provide strong indications of the
clumped
nature of their wind. Moreover, we first drew attention to some
late-O
dwarfs showing extremely weak wind signatures. Consequently, we
have
derived mass loss rates from STIS spectroscopy that are
significantly
lower than the current theoretical predictions used in
evolutionary
models. Because of the limited size of the current sample
(and
some clear bias toward stars with sharp-lined spectra), these
results
must however be viewed as tentative. Thanks to the high
efficiency
of COS in the FUV range, we propose now to obtain
high-resolution
FUV spectra with COS of a larger sample of SMC O stars
to
study systematically rotation and wind properties of massive stars at
low
metallicity. The analysis of the FUV wind lines will be based on our
2D
extension of CMFGEN to model axi-symmetric rotating winds.
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.
NIC2/WFC3/IR
11548
Infrared
Imaging of Protostars in the Orion A Cloud: The Role of
Environment
in Star Formation
We
propose NICMOS and WFC3/IR 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.
STIS/CC
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
STIS/CC
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.
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 followup by
JWST,
ALMA and EVLA.
WFC3/ACS/UVIS
11877
HST
Cycle 17 and Post-SM4 Optical Monitor
This
program is the Cycle 17 implementation of the HST Optical
Monitoring
Program.
The
36 orbits comprising this proposal will utilize ACS (Wide Field
Channel)
and WFC3 (UVIS Channel) to observe stellar cluster members in
parallel
with multiple exposures over an orbit. Phase retrieval
performed
on the PSF in each image will be used to measure primarily
focus,
with the ability to explore apparent coma, and astigmatism
changes
in WFC3.
The
goals of this program are to: 1) monitor the overall OTA focal
length
for the purposes of maintaining focus within science tolerances
2)
gain experience with the relative effectiveness of phase retrieval on
WFC3/UVIS
PSFs 3) determine focus offset between the imagers and
identify
any SI-specific focus behavior and dependencies
If
need is determined, future visits will be modified to interleave
WFC3/IR
channel and STIS/CCD focii measurements.
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/UVIS
11594
A
WFC3 Grism Survey for Lyman Limit Absorption at z=2
We
propose to conduct a spectroscopic survey of Lyman limit absorbers at
redshifts
1.8 < z < 2.5, using WFC3 and the G280 grism. This proposal
intends
to complete an approved Cycle 15 SNAP program (10878), which was
cut
short due to the ACS failure. We have selected 64 quasars at 2.3 < z
<
2.6 from the Sloan Digital Sky Survey Spectroscopic Quasar Sample, for
which
no BAL signature is found at the QSO redshift and no strong metal
absorption
lines are present at z > 2.3 along the lines of sight. The
survey
has three main observational goals. First, we will determine the
redshift
frequency dn/dz of the LLS over the column density range 16.0 <
log(NHI)
< 20.3 cm^-2. Second, we will measure the column density
frequency
distribution f(N) for the partial Lyman limit systems (PLLS)
over
the column density range 16.0 < log(NHI) < 17.5 cm^-2. Third, we
will
identify those sightlines which could provide a measurement of the
primordial
D/H ratio. By carrying out this survey, we can also help
place
meaningful constraints on two key quantities of cosmological
relevance.
First, we will estimate the amount of metals in the LLS using
the
f(N), and ground based observations of metal line transitions.
Second,
by determining f(N) of the PLLS, we can constrain the amplitude
of
the ionizing UV background at z~2 to a greater precision. This survey
is
ideal for a snapshot observing program, because the on-object
integration
times are all well below 30 minutes, and follow-up
observations
from the ground require minimal telescope time due to the
QSO
sample being bright.
WFC3/UVIS
11903
UVIS
Photometric Zero Points
This
proposal obtains the photometric zero points in 53 of the 62
UVIS/WFC3
filters: the 18 broad-band filters, 8 medium-band filters, 16
narrow-band
filters, and 11 of the 20 quad filters (those being used in
cycle
17). The observations will be primary obtained by observing the
hot
DA white dwarf standards GD153 and G191-B2B. A redder secondary
standard,
P330E, will be observed in a subset of the filters to provide
color
corrections. Repeat observations in 16 of the most widely used
cycle
17 filters will be obtained once per month for the first three
months,
and then once every second month for the duration of cycle 17,
alternating
and depending on target availability. These observations
will
enable monitoring of the stability of the photometric system.
Photometric
transformation equations will be calculated by comparing the
photometry
of stars in two globular clusters, 47 Tuc and NGC 2419, to
previous
measurements with other telescopes/instruments.
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/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.