HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5170
PERIOD
COVERED: 5am August 27 - 5am August 30, 2010 (DOY 239/09:00z-242/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12365
- GSAcq(1,2,1) at 240/23:21:19z took 2 attempts to acquire Fine Lock.
Observations possibly affected: WFC3 204 Proposal ID#11908, WFC3
205-206
& ACS 44-47 Proposal ID#11613, STIS 45 Proposal ID#11845, STIS
46-47
Proposal ID#11847.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES:
2066-0
- Update CCS SOI after COS FSW 4.11 installation @ 241/2345z
2061-0
- HST486/NSSC-1 SOI Configuration -- PRD 7.3 (closed) @ 241/2359z
2067-0
- COS EEPROM & Exec SOIs out of synch between install & active (closed)
@ 242/0001z
SCHEDULED SUCCESSFUL
FGS
GSAcq
19
19
FGS
REAcq
28
28
OBAD
with Maneuver 16 16
SIGNIFICANT
EVENTS:
Flash
Report: COS FSW 4.11 installation complete
COS
successfully transition down to boot and back-up to Operate (COS CS
FSW
4.11 was active at 242/02:50z).
OBSERVATIONS
SCHEDULED:
S/C
12046
COS
FUV DCE Memory Dump
Whenever
the FUV detector high voltage is on, count rate and current
draw
information is collected, monitored, and saved to DCE memory. Every
10
msec the detector samples the currents from the HV power supplies
(HVIA,
HVIB) and the AUX power supply (AUXI). The last 1000 samples are
saved
in memory, along with a histogram of the number of occurrences of
each
current value.
In
the case of a HV transient (known as a "crackle" on FUSE), where one
of
these currents exceeds a preset threshold for a persistence time, the
HV
will shut down, and the DCE memory will be dumped and examined as
part
of the recovery procedure. However, if the current exceeds the
threshold
for less than the persistence time (a "mini-crackle" in FUSE
parlance),
there is no way to know without dumping DCE memory. By
dumping
and examining the histograms regularly, we will be able to
monitor
any changes in the rate of "mini-crackles" and thus learn
something
about the state of the detector.
COS/NUV
12042
COS-GTO:
Pluto
We
seek to measure Pluto's albedo below 2100, to better constrain
surface
composition. COS observations will provide a substantial
improvement
in the S/N of Pluto spectra from <1800 to 2100. Accumulation
of
past HST/FOS spectra yields extremely low S/N below 2000 (S/N of only
1-3
in 100 bins; Krasnopolsky 2001). We expect to achieve S/N=5 at 1950
with
10 binning. In addition to spectrally broad albedo measurements,
these
observations could reveal line or molecular band emission, such as
C
I 1931 or CO 1993.
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.
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/UV
11922
UVIS
Fringing
Multiple
pointing observations of the globular cluster Omega Centauri
(NGC
5139) in the narrow band filters F656N and F953N will be used to
verify
the fringing model developed during various tests (TV3) and its
impact
on photometric accuracy. By measuring the relative changes in
brightness
of a star at different positions on the detector, we will
determine
the local variations induced by the fringing pattern.
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
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).
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
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
WFC3/IR
11738
SPIDERWEBS
AND FLIES: OBSERVING MASSIVE GALAXY FORMATION IN ACTION
Distant
luminous radio galaxies are among the brightest known galaxies
in
the early Universe, pinpoint likely progenitors of dominant cluster
galaxies
and are unique laboratories for studying massive galaxy
formation.
Spectacular images with the ACS and NICMOS of one such
object,
the "Spiderweb Galaxy" at z = 2.2, show in exquisite detail,
hierarchical
merging occurring 11 Gyr ago. By imaging 3 additional
Spiderweb-like
galaxies we wish to study this potentially crucial phase
of
massive galaxy evolution, when hierarchical merging, galaxy
downsizing
and AGN feedback are all likely to be occurring. Properties
of
the complete sample of Spiderweb galaxies will be used to (i)
constrain
models for the formation and evolution of the most massive
galaxies
that dominate rich clusters and (ii) investigate the nature of
chain
and tadpole galaxies, a fundamental but poorly understood
constituent
of the early Universe.
We
shall image rest-frame UV and optical continuum emission from 3 radio
galaxies
with 2.4 < z < 3.8 that appear clumpy and large in shallow
WFPC/PC
observations. The new observations will typically reach ~2
magnitudes
fainter over 20-40 times larger area than previously.
Photometric
and morphological parameters will be measured for satellite
galaxies
("flies") in the clumpy massive hosts and for galaxies in ~ 1.5
Mpc
x 1.5 Mpc regions of surrounding protoclusters. Locations, sizes,
elongations,
clumpiness, masses, and star formation rates of the merging
satellite
and protocluster galaxies will be compared with new state of
the
art simulations. Combination of ACS and WFC3 images will help
disentangle
the properties of the young and old populations.
Specific
goals include: (i) investigating star formation histories of
the
satellite galaxies and the extended emission,
(ii)
studying "downsizing" and merging scenarios and (iii) measuring the
statistics
of linear galaxies and relating them to models for the
formation
of massive galaxies and to the properties of the important but
enigmatic
class of chain/tadpole galaxies in the HUDF.
STIS/CCD/MA1
11737
The
Distance Dependence of the Interstellar N/O Abundance Ratio: A Gould
Belt
Influence?
The
degree of elemental abundance homogeneity in the interstellar medium
is
a function of the enrichment and mixing processes that govern
galactic
chemical evolution. Observations of young stars and the
interstellar
gas within ~500 pc of the Sun have revealed a local ISM
that
is so well-mixed it is having an impact on ideas regarding the
formation
of extrasolar planets. However, the situation just beyond the
local
ISM is not so clear. Sensitive UV absorption line measurements
have
recently revealed a pattern of inhomogeneities in the interstellar
O,
N, and Kr gas-phase abundances at distances of ~500 pc and beyond
that
appear nucleosynthetic in origin rather than due to dust depletion.
In
particular, based on a sample of 13 sightlines, Knauth et al. (2006)
have
found that the nearby stars (d < 500 pc) exhibit a mean
interstellar
N/O abundance ratio that is significantly higher (0.18 dex)
than
that toward the more distant stars. Interestingly, all of their
sightlines
lie in the sky vicinity of the Gould Belt of OB associations,
molecular
clouds, and diffuse gas encircling the Sun at a distance of
~400
pc. Is it possible that mixing processes have not yet smoothed out
the
recent ISM enrichment by massive stars in the young Belt region? By
measuring
the interstellar N/O ratios in a strategic new sample of
sightlines
with STIS, we propose to test the apparent N/O homogeneity
inside
the Gould Belt and determine if the apparent decline in the N/O
ratio
with distance is robust and associated with the Belt region.
ACS/WFC3
11734
The
Hosts of High Redshift Gamma-Ray Bursts
Gamma-ray
bursts are the most luminous explosive events known, acting as
beacons
to the high redshift universe. Long duration GRBs have their
origin
in the collapse of massive stars and thus select star forming
galaxies
across a wide range of redshift. Due to their bright afterglows
we
can study the details of GRB host galaxies via absorption
spectroscopy,
providing redshifts, column densities and metallicities
for
galaxies far too faint to be accessible directly with current
technology.
We have already obtained deep ground based observations for
many
hosts and here propose ACS/WFC3 and WFC3 observations of the fields
of
bursts at z>3 which are undetected in deep ground based images. These
observations
will study the hosts in emission, providing luminosities
and
morphologies and will enable the construction of a sample of high-z
galaxies
with more detailed physical properties than has ever been
possible
before.
WFC3/IR
11708
Determining
the Sub-stellar IMF in the Most Massive Young Milky Way
Cluster,
Westerlund 1
Despite
over 50 years of active research, a key question in galactic
astronomy
remains unanswered: is the initial mass function (IMF) of
stars
and sub-stellar objects universal, or does it depend on initial
conditions?
The answer has profound consequences for the evolution of
galaxies
as well as a predictive theory of star formation. Work to date
suggests
that certain environments (high densities, e.g. Elmegreen 2004;
low
metallicity, e.g. Larson 2005) should produce a top-heavy IMF, and
there
are hints from unresolved star-bursts that this might be the case.
Yet,
there is no clear evidence for an IMF that differs from that
characterizing
the Galactic field stars in a resolved stellar population
down
to one solar mass. Westerlund 1 is the most massive young star
cluster
known in the Milky Way. With an estimated mass of 5x10^4 Msun,
an
age of 3-5 Myr, and located at a distance of 3-4 kpc, it presents a
unique
opportunity to test whether the IMF in such a cluster deviates
from
the norm well down into the brown dwarf regime. We propose WFC3
near-IR
imaging to probe the IMF down to 40 Jupiter masses. The data
will
enable use to: 1) provide a stringent test of the universality of
the
IMF under conditions approximating those of star-bursts; 2) search
for
primordial or dynamic mass segregation in the clusters; and 3)
assess
whether the cluster is likely to remain bound (as a massive open
cluster)
or disperse into the field. We will obtain images in the F125W,
F160W,
and F139M filters. The F139M filter covers a strong water
absorption
feature and the color F125W/F139M is a powerful temperature
diagnostic
in the range 2800-4000 K. This information will enable us to:
a)
confirm membership for low mass stars suspected on the basis of their
position
in the color-magnitude diagram; b) place the members in the HR
diagram;
and c) estimate the masses and ages of cluster members for
low-mass
stars and sub-stellar objects. This new capability offered with
the
WFC3 (through a novel combination of filter complement, high spatial
resolution,
and large field of view) will enable us to make a
fundamental
test of whether the IMF is universal on a unique resolved
stellar
population, as well as assess the clusters structure, dynamics,
and
ultimate fate.
WFC3/IR
11694
Mapping
the Interaction Between High-Redshift Galaxies and the
Intergalactic
Environment
With
the commissioning of the high-throughput large-area camera WFC3/IR,
it
is possible for the first time to undertake an efficient survey of
the
rest-frame optical morphologies of galaxies at the peak epoch of
star
formation in the universe. We therefore propose deep WFC3/IR
imaging
of over 320 spectroscopically confirmed galaxies between
redshift
1.6 < z < 3.4 in well-studied fields which lie along the line
of
sight to bright background QSOs. The spectra of these bright QSOs
probe
the IGM in the vicinity of each of the foreground galaxies along
the
line of sight, providing detailed information on the physical state
of
the gas at large galactocentric radii. In combination with our
densely
sampled UV/IR spectroscopy, stellar population models, and
kinematic
data in these fields, WFC3/IR imaging data will permit us to
construct
a comprehensive picture of the structure, dynamics, and star
formation
properties of a large population of galaxies in the early
universe
and their effect upon their cosmological environment.
WFC3/UV/IR
11664
The
WFC3 Galactic Bulge Treasury Program: Populations, Formation
History,
and Planets
Exploiting
the full power of the Wide Field Camera 3 (WFC3), we propose
deep
panchromatic imaging of four fields in the Galactic bulge. These
data
will enable a sensitive dissection of its stellar populations,
using
a new set of reddening-free photometric indices we have
constructed
from broad-band filters across UV, optical, and near-IR
wavelengths.
These indices will provide accurate temperatures and
metallicities
for hundreds of thousands of individual bulge stars.
Proper
motions of these stars derived from multi-epoch observations will
allow
separation of pure bulge samples from foreground disk
contamination.
Our catalogs of proper motions and panchromatic
photometry
will support a wide range of bulge studies.
Using
these photometric and astrometric tools, we will reconstruct the
detailed
star-formation history as a function of position within the
bulge,
and thus differentiate between rapid- and extended-formation
scenarios.
We will also measure the dependence of the stellar mass
function
on metallicity, revealing how the characteristic mass of star
formation
varies with chemistry. Our sample of bulge stars with accurate
metallicities
will include 12 candidate hosts of extrasolar planets.
Planet
frequency is correlated with metallicity in the solar
neighborhood;
our measurements will extend this knowledge to a remote
environment
with a very distinct chemistry.
Our
proposal also includes observations of six well-studied globular and
open
star clusters; these observations will serve to calibrate our
photometric
indices, provide empirical population templates, and
transform
the theoretical isochrone libraries into the WFC3 filter
system.
Besides enabling our own program, these products will provide
powerful
new tools for a host of other stellar-population investigations
with
HST/WFC3. We will deliver all of the products from this Treasury
Program
to the community in a timely fashion.
WFC3/UVIS
11630
Monitoring
Active Atmospheres on Uranus and Neptune
We
propose Snapshot observations of Uranus and Neptune to monitor
changes
in their atmospheres on time scales of weeks and months, as we
have
been doing for the past seven years. Previous Hubble Space
Telescope
observations (including previous Snapshot programs 8634,
10170,
10534, and 11156), together with near-IR images obtained using
adaptive
optics on the Keck Telescope, reveal both planets to be dynamic
worlds
which change on time scales ranging from hours to (terrestrial)
years.
Uranus equinox occurred in December 2007, and the northern
hemisphere
is becoming fully visible for the first time since the early
1960s.
HST observations during the past several years (Hammel et al.
2005,
Icarus 175, 284 and references therein) have revealed strongly
wavelength-dependent
latitudinal structure, the presence of numerous
visible-wavelength
cloud features in the northern hemisphere, at least
one
very long-lived discrete cloud in the southern hemisphere, and in
2006
the first clearly defined dark spot seen on Uranus. Long term
ground-based
observations (Lockwood and Jerzekiewicz, 2006, Icarus 180,
442;
Hammel and Lockwood 2007, Icarus 186, 291) reveal seasonal
brightness
changes that seem to demand the appearance of a bright
northern
polar cap within the next few years. Recent HST and Keck
observations
of Neptune (Sromovsky et al. 2003, Icarus 163, 256 and
references
therein) show a general increase in activity at south
temperate
latitudes until 2004, when Neptune returned to a rather
Voyager-like
appearance with discrete bright spots rather than active
latitude
bands. Further Snapshot observations of these two dynamic
planets
will elucidate the nature of long-term changes in their zonal
atmospheric
bands and clarify the processes of formation, evolution, and
dissipation
of discrete albedo features.
STIS/CCD/MA1/MA2
11616
The
Disks, Accretion, and Outflows (DAO) of T Tau Stars
Classical
T Tauri stars undergo magnetospheric accretion, power
outflows,
and possess the physical and chemical conditions in their
disks
to give rise to planet formation. Existing high resolution FUV
spectra
verify that this spectral region offers unique diagnostics of
these
processes, which have the potential to significantly advance our
understanding
of the interaction of a star and its accretion disk. To
date
the limited results are intriguing, with dramatic differences in
kinematic
structure in lines ranging from C IV to H2 among the few stars
that
have been observed. We propose to use HST/COS to survey the disks,
outflows,
and accretion (the DAO) of 26 CTTS and 6 WTTS in the FUV at
high
spectral resolution. A survey of this size is essential to
establish
how properties of accretion shocks, winds and disk irradiation
depend
on disk accretion rate. Specifically, our goals are to (1)
measure
the radiation from and understand the physical properties of the
gas
very near the accretion shock as a function of accretion rate using
emission
line profiles of hot lines (C IV, Si IV, N V, and He II); (2)
measure
the opacity, velocity, and temperature at the base of the
outflow
to constrain outflow models using wind absorption features; and
(3)
characterize the radiation incident on disks and protoplanetary
atmospheres
using H2 line and continuum emission and reconstructed
bright
Ly-alpha line emission.
WFC3/ACS/UVIS
11613
GHOSTS:
Stellar Outskirts of Massive Spiral Galaxies
We
propose to continue our highly successful GHOSTS HST survey of the
resolved
stellar populations of nearby, massive disk galaxies using
SNAPs.
These observations provide star counts and color-magnitude
diagrams
2-3 magnitudes below the tip of the Red Giant Branch of the
outer
disk and halo of each galaxy. We will measure the metallicity
distribution
functions and stellar density profiles from star counts
down
to very low average surface brightnesses, equivalent to ~32 V-mag
per
square arcsec.
This
proposal will substantially improve our unique sampling of galaxy
outskirts.
Our targets cover a range in galaxy mass, luminosity,
inclination,
and morphology. As a function of these galaxy properties,
this
survey provides: - the most extensive, systematic measurement of
radial
light profiles and axial ratios of the diffuse stellar halos and
outer
disks of spiral galaxies; - a comprehensive analysis of halo
metallicity
distributions as function of galaxy type and position within
the
galaxy; - an unprecedented study of the stellar metallicity and age
distribution
in the outer disk regions where the disk truncations occur;
-
the first comparative study of globular clusters and their field
stellar
populations.
We
will use these fossil records of the galaxy assembly process to test
halo
formation models within the hierarchical galaxy formation scheme.
ACS/WFC3
11604
The
Nuclear Structure of OH Megamaser Galaxies
We
propose a snapshot survey of a complete sample of 80 OH megamaser
galaxies.
Each galaxy will be imaged with the ACS/WFC through F814W and
a
linear ramp filter (FR656N or FR716N or FR782N or FR853N) allowing us
to
study both the spheroid and the gas morphology in Halpha + [N II]. We
will
use the 9% ramps FR647M (5370-7570 angstroms) centered at 7000
angstroms
and FR914M (7570-10, 719 angstroms) 8000 angstroms for
continuum
subtraction for the high and low z objects respectively. OH
megamaser
galaxies (OHMG) form an important class of ultraluminous
IR-galaxies
(ULIRGs) whose maser lines emit QSO-like luminosities.
ULIRGs
in general are associated with recent mergers but it is often
unclear
whether their power output is dominated by starbursts or a
hidden
QSO because of the high absorbing columns which hide their nuclei
even
at X-ray wavelengths. In contrast, OHMG exhibit strong evidence for
the
presence of an energetically important and recently triggered active
nucleus.
In particular it is clear that much of the gas must have
already
collapsed to form a nuclear disk which may be the progenitor of
a
circum-nuclear torus, a key element of the unified scheme of AGN. A
great
advantage of studying OHMG systems over the general ULIRG
population,
is that the circum-nuclear disks are effectively "fixed" at
an
inner, edge on, orientation, eliminating varying inclination as a
nuisance
parameter. We will use the HST observations in conjunction with
existing
maser and spectroscopic data to construct a detailed picture of
the
circum-nuclear regions of a hitherto relatively neglected class of
galaxy
that may hold the key to understanding the relationship between
galaxy
mergers, nuclear star- formation, and the growth of massive black
holes
and the triggering of nuclear activity.