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HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5193
PERIOD
COVERED: 8:00pm September 29 - 7:59pm September 30, 2010 (DOY
273/00:00z-273/23:59z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12441
- ACS Suspend at 273/11:51z
Observations affected: ACS #62-65, Proposal #11575
12442
- GSAcq(2,1,1) scheduled at 273/16:44:20z results in fine lock backup (2,0,2),
scan step limit exceeded on FGS-2.
Observations possibly affected: COS 95-100 Proposal ID#12041, WFC3
164
Proposal ID#12348
COMPLETED
OPS REQUEST:
18931-2
- Dump ACS memory at 273/1312z
18932-1
- Recover ACS from Suspend Mode at 273/2103z
COMPLETED
OPS NOTES: (None)
Scheduled
Successful
FGS
GSAcq
8
8
FGS
REAcq
7
7
OBAD
with Maneuver 6
6
SIGNIFICANT
EVENTS:
FLASH
REPORT: ACS Suspended at 273/11:51z.
FLASH
REPORT: ACS Suspend Recovery Side 1 was successfully completed at
2010/273/21:03
UTC, returning ACS to its nominal WFHROper state in
readiness
to intercept the on-going science timeline.
OBSERVATIONS
SCHEDULED:
ACS/WFC/WFC3/UV
12213
The
Stellar Halo Profiles of Massive Disk Galaxies
Stellar
halos surrounding massive galaxies are of prime interest in
hierarchical
galaxy formation models: most of the halo is formed by the
very
early accretion of small, metal poor satellite galaxies each with
their
independent evolution history. As such, halos contain the fossil
remnants
of the earliest star formation and accretion phases of a galaxy
in
formation. The resulting size, shape, age, and metallicity of stellar
halos
provide therefore a direct test of the basic ingredients
(reionization,
feedback from star formation, density fluctuation power
spectrum)
of hierarchical galaxy formation models.
In
our GHOSTS survey we have sampled the principle axes of a sample of
11
nearby galaxies with Vrot>100 km/s. Our detection of resolved stellar
halo
populations ~1.5 mag below the tip of the Red Giant Branch has
revealed
halos that extend as far as 30 kpc around the most massive
galaxies
in our sample. Those extended stellar halos seem more compact
than
current model predictions, they have unexpectedly high metallicity
up
to the last detected point, and have a luminosity that is more
closely
related to the bulge luminosity than to the galaxy mass. We
propose
to extend the light profiles of 4 massive galaxies with a range
in
bulge-to-disk ratio to the background limit at ~70 kpc. This will
enable
us to:
-
confirm the stellar halo shape (compactness) and assess with
confidence
any conflict with models using these very extended and
accurate
halo profile characterizations;
-
establish whether stellar envelopes beyond 30 kpc are still
morphologically
connected to inner bulges, or whether a break occurs at
larger
radii revealing a distinct new component;
-
determine whether every massive galaxy has an old, metal-poor halo at
large
radius like the Milky Way and M31; if not, constrain for the first
time
the range of stellar metallicity gradients in extended stellar
halos.
ACS/WFC3
11575
The
Stellar Origins of Supernovae
Supernovae
(SNe) have a profound effect on galaxies, and have been used
recently
as precise cosmological probes, resulting in the discovery of
the
accelerating Universe. They are clearly very important events
deserving
of intense study. Yet, even with nearly 4000 known SNe, we
know
relatively little about the stars which give rise to these powerful
explosions.
The main limitation has been the lack of spatial resolution
in
pre-SN imaging data. However, since 1999 our team has been at the
vanguard
of directly identifying SN progenitor stars in HST images. From
this
exciting new line of study, the emerging trend from 5 detections
for
Type II- Plateau SNe is that their progenitors appear to be
relatively
low mass (8 to 20 Msun) red supergiants, although more cases
are
needed. Nonetheless, the nature of the progenitors of Type Ib/c SNe,
a
subset of which are associated with the amazing gamma-ray bursts,
remains
ambiguous. Furthermore, we remain in the continually
embarrassing
situation that we still do not yet know which progenitor
systems
explode as Type Ia SNe, which are currently being used for
precision
cosmology. In Cycle 16 we have triggered on the Type Ic SN
2007gr
and Type IIb SN 2008ax so far. We propose to determine the
identities
of the progenitors of 4 SNe within 17 Mpc, which we expect to
occur
during Cycle 17, through ToO observations using ACS/HRC.
COS/FUV
11526
COS-GTO:
Sampling the Local ISM with Hot White Dwarfs
We
shall use hot white dwarf stars located within 150pc of the Sun to
probe
the absorption properties of the interstellar gas associated with
the
local cavity. There is still much debate concerning the ionization
state
of the local gas, since previously detected highly ionized lines
(such
as CIV and SiIV) could be associated with the circumstellar
environments
of hot white dwarfs. By using a priori knowledge of the
velocity
structure of the interstellar sight-lines to these targets
(gained
from high spectral resolution ground-based observations) in
conjunction
with the UV absorption data gained with HST-COS, we shall be
able
to better determine both the physical and chemical state of the
numerous
diffuse interstellar clouds present within the local cavity.
COS/NUV
12041
COS-GTO:
Io Atmosphere/STIS
We
will use six HST orbits with COS to observe the disk-integrated
longitudinal
distribution of Io's atmosphere, and ten HST orbits with
STIS
to provide complementary disk-resolved information at key
locations.
We will use the COS G225M grating to observe four SO2
absorption
bands, which can be used to determine SO2 atmospheric
density.
Disk-integrated 19 micron observations of the atmosphere
indicate
that the anti-Jupiter hemisphere of Io has an atmospheric
density
roughly ten times greater than the Jupiter-facing side (Spencer
et
al. 2005), and mm-wave observations suggest a similar pattern.
However
the infrared and mm-wave observations cannot easily separate
atmospheric
density from atmospheric temperature, so these results are
model-dependent.
Sparse 2100 2300 disk-resolved observations
(McGrath
et al. 2000, Jessup et al. 2004) tell a consistent story, but
do
not cover enough of Io's surface to provide full confirmation of the
long-wavelength
result. We will therefore observe Io's disk-integrated
atmospheric
density at six longitudes, roughly 30, 90, 150, 210, 270,
and
330 W, to confirm the 19 micron results and improve our ability to
model
the 19-micron data. With STIS, we plan disk-resolved 2000-3200
spectroscopy
of Io's SO2 atmosphere. Our observations will target
low-latitude
regions away from active plumes (in contrast to our Cycle
10
observations (Jessup et al. 2004) which targeted the Prometheus
plume),
to look for the effect of plumes on the atmosphere. We will also
look
at the variation of low-latitude atmospheric abundance with terrain
type,
to look for explanations for the large longitudinal variations in
atmospheric
pressure to be studied with COS. Finally, we will look at a
variety
of regions at two different times of day to determine the extent
of
diurnal variations in the atmosphere, which are expected if the
atmosphere
is dominantly supported by frost sublimation.
COS/NUV/FUV
11728
The
Impact of Starbursts on the Gaseous Halos of Galaxies
Perhaps
the most important (yet uncertain) aspects of galaxy evolution
are
the processes by which galaxies accrete gas and by which the
resulting
star formation and black hole growth affects this accreting
gas.
It is believed that both the form of the accretion and the nature
of
the feedback change as a function of the galaxy mass. At low mass the
gas
comes in cold and the feedback is provided by massive stars. At high
mass,
the gas comes in hot, and the feedback is from an AGN. The
changeover
occurs near the mass where the galaxy population transitions
from
star-forming galaxies to red and dead ones. The population of red
and
dead galaxies is building with cosmic time, and it is believed that
feedback
plays an important role in this process: shutting down star
formation
by heating and/or expelling the reservoir of cold halo gas. To
investigate
these ideas, we propose to use COS far-UV spectra of
background
QSOs to measure the properties of the halo gas in a sample of
galaxies
near the transition mass that have undergone starbursts within
the
past 100 Myr to 1 Gyr. The galactic wind associated with the
starburst
is predicted to have affected the properties of the gaseous
halo.
To test this, we will compare the properties of the halos of the
post-starburst
galaxies to those of a control sample of galaxies matched
in
mass and QSO impact parameter. Do the halos of the post-starburst
galaxies
show a higher incidence rate of Ly-Alpha and metal
absorption-lines?
Are the kinematics of the halo gas more disturbed in
the
post-starbursts? Has the wind affected the ionization state and/or
the
metallicity of the halo? These data will provide fresh new insights
into
the role of feedback from massive stars on the evolution of
galaxies,
and may also offer clues about the properties of the QSO metal
absorption-line
systems at high-redshift .
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.
WFC3/IR
11696
Infrared
Survey of Star Formation Across Cosmic Time
We
propose to use the unique power of WFC3 slitless spectroscopy to
measure
the evolution of cosmic star formation from the end of the
reionization
epoch at z>6 to the close of the galaxy-building era at
z~0.3.Pure
parallel observations with the grisms have proven to be
efficient
for identifying line emission from galaxies across a broad
range
of redshifts. The G102 grism on WFC3 was designed to extend this
capability
to search for Ly-alpha emission from the first galaxies.
Using
up to 250 orbits of pure parallel WFC3 spectroscopy, we will
observe
about 40 deep (4-5 orbit) fields with the combination of G102
and
G141, and about 20 shallow (2-3 orbit) fields with G141 alone.
Our
primary science goals at the highest redshifts are: (1) Detect Lya
in
~100 galaxies with z>5.6 and measure the evolution of the Lya
luminosity
function, independent of of cosmic variance; 2) Determine the
connection
between emission line selected and continuum-break selected
galaxies
at these high redshifts, and 3) Search for the proposed
signature
of neutral hydrogen absorption at re-ionization. At
intermediate
redshifts we will (4) Detect more than 1000 galaxies in
Halpha
at 0.5<z<1.8 to measure the evolution of the extinction-corrected
star
formation density across the peak epoch of star formation. This is
over
an order-of-magnitude improvement in the current statistics, from
the
NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from
0.5<z<2.2;
and (6) Estimate the evolution in reddening and metallicty in
star-forming
galaxies and measure the evolution of the Seyfert
population.
For hundreds of spectra we will be able to measure one or
even
two line pair ratios -- in particular, the Balmer decrement and
[OII]/[OIII]
are sensitive to gas reddening and metallicity. As a bonus,
the
G102 grism offers the possibility of detecting Lya emission at
z=7-8.8.
To
identify single-line Lya emitters, we will exploit the wide
0.8--1.9um
wavelength coverage of the combined G102+G141 spectra. All
[OII]
and [OIII] interlopers detected in G102 will be reliably separated
from
true LAEs by the detection of at least one strong line in the G141
spectrum,
without the need for any ancillary data. We waive all
proprietary
rights to our data and will make high-level data products
available
through the ST/ECF.
WFC3/IR
12265
Determining
the Physical Nature of a Unique Giant Lya Emitter at z=6.595
We
propose deep WFC3/IR imaging for a giant Lya emitter (LAE) with a
Keck
spectroscopic redshift of z=6.595 discovered by extensive
narrow-band
imaging with Subaru in the SXDS-UKIDSS/UDS field. This
remarkable
object is unique in many respects including its large stellar
mass
and luminous nebula which extends over 17 kpc; no equivalent source
has
been found in other surveys. The nature of this rare object is
unclear.
Fundamental to progress is determining the origin of star
formation
in such an early massive object; if the age of the stellar
population
is short we are likely witnessing a special moment in the
formation
history of a massive galaxy. The heating source for the nebula
is
also unclear; options include intense star formation, the infall of
cold
gas onto a dark halo or shock heating from a merger. We will take
deep
broad-band (F125W and F160W) images and an intermediate-band
(F098M)
image which will be analyzed in conjunction with ultra-deep IRAC
3.6
and 4.5 micron data being taken by the Spitzer/SEDS project. These
data
will enable us to constrain the star formation rate and stellar
age.
Moreover, the UV continuum morphology and Lya-line distribution
will
be investigated for evidence of a major merger, cold accretion, or
hot
bubbles associated with outflows. We will address the physical
origin
of the remarkable object observed at an epoch where massive
galaxies
are thought to begin their assembly.
WFC3/IR
12307
A
public SNAPSHOT Survey of Gamma-ray Burst Host Galaxies
We
propose to conduct a public infrared survey of the host galaxies of
Swift
selected gamma-ray bursts (GRBs) at z<3. By obtaining deep,
diffraction
limited imaging in the IR we will complete detections for
the
host galaxies, and in concert with our extensive ground based
afterglow
and host programmes will compile a detailed catalog of the
properties
of high-z galaxies selected by GRBs. In particular these
observations
will enable us to study the colours, luminosities and
morphologies
of the galaxies. This in turn informs studies of the nature
of
the progenitors and the role of GRBs as probes of star formation
across
cosmic history. Ultimately it provides a product of legacy value
which
will greatly complement further studies with next generation
facilities
such as ALMA and JWST.
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
12348
WFC3/UVIS
Charge Injection Test
In
preparation for making charge injection (CI) available to observers,
this
proposal will 1) confirm that the CI performs on-orbit as it did on
the
ground, 2) provide an initial assessment of which CI mode is most
effective
(10, 17, 25 line or continuous), and 3) obtain a baseline
calibration
for each mode.
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.