HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5091
PERIOD
COVERED: 5am May 6 - 5am May 7, 2010 (DOY 126/09:00z-127/09:00z)
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:
18854-3
– Recover STIS MAMA1 from HV shutoff @
126/1914z
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
6
6
FGS
REAcq
9
9
OBAD
with Maneuver 4
4
SIGNIFICANT
EVENTS:
Ops
Flash Report:
STIS
MAMA1 HV ramp was successfully competed at 126/22:52z; the max
counts
observed during the ramp was 158 cnts/secs.
OBSERVATIONS
SCHEDULED
COS/NUV/FUV
11645
HST
COS Observations of the Atmosphere and Airglow/Aurora of Enceladus
Recent
observations from several instruments on the Cassini spacecraft
have
revealed plumes of dust and water from the southern polar region,
and
clearly shown that Enceladus contributes large amounts of plasma to
Saturn?s
magnetosphere. This implies a global thin atmosphere containing
water
and likely other species, and a local region with orders of
magnitude
higher density near the plumes. While water and dust have been
identified
from the plumes, the presence of many other species in the
atmosphere
is possible and not yet ruled out. The identification of all
significant
species in the atmosphere of Enceladus is of key importance
to
speculation about the source of the water plumes, and the
implications
for any form of life at or below the surface. In addition,
modeling
suggests that Enceladus? mass loading region may be comparable
in
extent to Io?s, and interacts strongly with Saturn?s corotating
magnetic
field and plasma. We have recently concluded a search for an
auroral
footprint of Enceladus in HST images, which set a low upper
limit
implying that the magnetospheric interaction is concentrated near
Enceladus,
rather than being communicated along field lines to Saturn?s
ionosphere.
The next step will be to observe the interaction at the
satellite,
and to learn whatever we can about the physics of the release
of
the atmospheric gas. We propose here an exploratory set of spectral
observations
with HST COS to measure the solar reflection spectrum over
a
broad range of UV wavelengths for atmospheric absorption signatures.
This
will at the same time measure the emission spectrum of the
atmosphere
from both the leading and trailing hemispheres ? Enceladus
orbit
apart, as was done in HST STIS observations of Io to study its
interaction
at Jupiter. The higher sensitivity of COS will be needed to
study
the much smaller and relatively weakly-interacting Enceladus, and
the
outcome of these observations will determine the nature of future
studies
of the atmosphere of Enceladus and its plasma interaction with
the
Saturnian magnetosphere.
COS/NUV/FUV
11698
The
Structure and Dynamics of Virgo's Multi-Phase Intracluster Medium
The
dynamical flows of the intracluster medium (ICM) are largely
unknown.
We propose to map the spatial and kinematic distribution of the
warm
ICM of the nearby Virgo cluster using the Cosmic Origins
Spectrograph.
15 sightlines at a range of impact parameters within the
virial
radius of the cluster (0.2 - 1.7 Mpc) will be probed for
Lyman-alpha
absorption and the data compared to blind HI, dust and x-ray
surveys
to create a multi-phase map of the cluster's ICM. Absorption
line
sightlines are commonly 40-100 kpc from a galaxy, allowing the flow
of
baryons between galaxies and the ICM to be assessed. The velocity
distribution
of the absorbers will be directly compared to simulations
and
used to constrain the turbulent motions of the ICM. This proposal
will
result in the first map of a cluster's warm ICM and provide
important
tests for our theoretical understanding of cluster formation
and
the treatment of gas cooling in cosmological simulations.
COS/NUV/FUV
11720
Detailed
Analysis of Carbon Atmosphere White Dwarfs
We
propose to obtain UV spectra for the newly discovered white dwarf
stars
with a carbon- dominated atmosphere. Model calculations show that
these
stars emit most of their light in the UV part of the
electromagnetic
spectrum and that an accurate determination of the flux
in
this region is crucial for an accurate determination of the
atmospheric
parameters. It will also provide a unique opportunity to
test
the atomic data and broadening theory in stellar conditions never
met
before. This will play a primordial role in our path to understand
the
origin of these objects as well to obtain a better understanding of
the
evolution of stars in general. The principal objective we hope to
achieve
with these observations are 1) obtain accurate surface
gravity/mass
for these stars, 2) constrain/determine the abundance of
other
elements (O, He, Mg, Ne etc.), especially oxygen, 3) verify the
accuracy
of the various theoretical atomic data used in the model
calculations,
4) understand the origin and evolution of carbon
atmosphere
white dwarfs, in particular whether progenitor stars as
massive
as 10.5 solar masses can produce white dwarfs, rather than
supernovae.
We propose to observe 5 objects chosen carefully to cover
the
range of observed properties among carbon atmosphere white dwarfs
(effective
temperature, surface gravity, abundance of hydrogen/helium
and
magnetic field).
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.
STIS/CCD
11606
Dynamical
Hypermassive Black Hole Masses
We
will use STIS spectra to derive the masses of 5 hypermassive black
holes
(HMBHs). From the observed scaling relations defined by less
massive
spheroids, these objects are expected to reside at the nuclei of
host
galaxies with stellar velocity dispersions greater than 320 km/s.
These
5 targets have confirmed regular gas distributions on the scales
of
the black hole sphere of influence. It is essential that the sphere
of
influence is resolved for accurate determinations of black hole mass
(0.1").
These scales cannot be effectively observed from the ground.
Only
two HMBHs have had their masses modeled so far; it is impossible to
draw
any general conclusions about the connections between HMBH mass and
their
massive host galaxies. With these 5 targets we will determine
whether
these HMBHs deviate from the scaling relations defined by less
massive
spheroids. A larger sample will allow us to firmly anchor the
high
mass end of the correlation between black hole mass and stellar
velocity
dispersion, and other scaling relations. Therefore we are also
conducting
a SNAPshot program with which we expect to detect a further
24
HMBH candidates for STIS observation in future cycles. At the
completion
of this project we will have populated the high mass end of
the
scaling relations with the sample sizes enjoyed by less massive
spheroids.
STIS/MA
11856
MAMA
Full Field Sensitivity Monitor & PSF Check
The
purpose of this program is to monitor the sensitivity of the MAMA
detectors
over the full field. This is achieved by observing globular
cluster
NGC6681 once during Cycle 17. The data can be directly compared
with
similar data obtained in Cycles 7, 8, 9, 10, 11, and 12.
STIS/MA1
11861
MAMA
FUV Flats
This
program will obtain FUV-MAMA observations of the STIS internal
Krypton
lamp to construct an FUV flat applicable to all FUV modes.
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
11602
High-resolution
imaging of three new UV-bright lensed arcs
We
have identified and spectroscopically confirmed three new strongly
lensed,
UV-bright star-forming galaxies at z ~ 2 that are similar to the
well-studied
gravitationally lensed Lyman Break Galaxy (LBG)
MS1512-cB58,
and are of comparable brightness to the ''8 O'Clock Arc''
(Allam
et al. 2007) and ''Clone'' systems (Lin et al. 2008). The 8
O'Clock
Arc and Clone have already been awarded 20 orbits for deep WFPC2
and
NICMOS imaging in five bands (HST cycle 16, Program 11167, PI:
Allam).
Adding these three recently discovered objects thus completes a
unique
set of the brightest known strongly lensed galaxies at z ~ 2,
with
magnitudes of r~20-21, and they provide a new window into the
detailed
study of the properties of high redshift galaxies. We propose
21
orbits for deep WFC3 imaging in five bands (F475W, F606W, F814W,
F110W,
and F160W) in order to construct detailed lensing models, to
probe
the mass and light profiles of the lensing galaxies and their
environments,
and to constrain the spectral energy distributions, star
formation
histories, and morphologies of the lensed galaxies.
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/IR
11662
Improving
the Radius-Luminosity Relationship for Broad-Lined AGNs with a
New
Reverberation Sample
The
radius-luminosity (R-L) relationship is currently the fundamental
basis
for all techniques used to estimate black hole masses in AGNs, in
both
the nearby and distant universe. However, the current R-L
relationship
is based on 34 objects that cover a limited range in black
hole
mass and luminosity. To improve our understanding of black hole
growth
and evolution, the R-L relationship must be extended to cover a
broader
range of black hole masses using the technique known as
reverberation
mapping. To this end, we have been awarded an
unprecedented
64 nights on the Lick Observatory 3-m telescope between
March
24 and May 31, 2008, to spectroscopically monitor 12 AGNs in order
to
measure their black hole masses. To properly determine the
luminosities
of these 12 AGNs, we must correct them for their
host-galaxy
starlight contributions using high-resolution images.
Previous
work by Bentz et al. (2006) has shown that the starlight
correction
to AGN luminosity measurements is an essential component to
interpreting
the R-L relationship. The correction will be substantial
for
each of the 12 sources we will monitor, as the AGNs are relatively
faint
and embedded in nearby, bright galaxies. Starlight corrections are
not
possible with ground-based images, as the PSF and bulge
contributions
become indistinguishable under typical seeing conditions,
and
adaptive optics are not yet operational in the spectral range where
the
corrections are needed. In addition, spectral decompositions are
very
model-dependent and are limited by the degree of accuracy to which
we
understand emission processes and stellar populations in galaxies.
Without
correcting for starlight, we will be unable to apply the results
of
our Spring 2008 campaign to the body of knowledge from previous
reverberation
mapping work. Therefore, we propose to obtain high
resolution,
high dynamic range images of the host galaxies of the 12
AGNs
in our ground-based monitoring sample, as well as one white dwarf
which
will be used as a PSF model.
WFC3/UVIS/IR
11700
Bright
Galaxies at z>7.5 with a WFC3 Pure Parallel Survey
The
epoch of reionization represents a special moment in the history of
the
Universe as it is during this era that the first galaxies and star
clusters
are formed. Reionization also profoundly affects the
environment
where subsequent generations of galaxies evolve. Our
overarching
goal is to test the hypothesis that galaxies are responsible
for
reionizing neutral hydrogen. To do so we propose to carry out a pure
parallel
WFC3 survey to constrain the bright end of the redshift z>7.5
galaxy
luminosity function on a total area of 176 arcmin^2 of sky.
Extrapolating
the evolution of the luminosity function from z~6, we
expect
to detect about 20 Lyman Break Galaxies brighter than M_* at z~8
significantly
improving the current sample of only a few galaxies known
at
these redshifts. Finding significantly fewer objects than predicted
on
the basis of extrapolation from z=6 would set strong limits to the
brightness
of M_*, highlighting a fast evolution of the luminosity
function
with the possible implication that galaxies alone cannot
reionize
the Universe. Our observations will find the best candidates
for
spectroscopic confirmation, that is bright z>7.5 objects, which
would
be missed by small area deeper surveys. The random pointing nature
of
the program is ideal to beat cosmic variance, especially severe for
luminous
massive galaxies, which are strongly clustered. In fact our
survey
geometry of 38 independent fields will constrain the luminosity
function
like a contiguous single field survey with two times more area
at
the same depth. Lyman Break Galaxies at z>7.5 down to m_AB=26.85 (5
sigma)
in F125W will be selected as F098M dropouts, using three to five
orbits
visits that include a total of four filters (F606W, F098M, F125W,
F160W)
optimized to remove low-redshift interlopers and cool stars. Our
data
will be highly complementary to a deep field search for high- z
galaxies
aimed at probing the faint end of the luminosity function,
allowing
us to disentangle the degeneracy between faint end slope and
M_*
in a Schechter function fit of the luminosity function. We waive
proprietary
rights for the data. In addition, we commit to release the
coordinates
and properties of our z>7.5 candidates within one month from
the
acquisition of each field.