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Daily Report #5090



 
 
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Old May 6th 10, 07:07 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5090

HUBBLE SPACE TELESCOPE - Continuing To Collect World Class Science

DAILY REPORT #5090

PERIOD COVERED: 05:00 am May 5, 2010 - 05:00 am May 6, 2010 (DOY 125/0900z - 126/0900z)

OBSERVATIONS SCHEDULED:
COS/FUV 11687

SNAPing Coronal Iron

This is a Snapshot Survey to explore two forbidden lines of highly
ionized iron in late-type coronal sources. Fe XII 1349 (T~ 2 MK) and
Fe XXI 1354 (T~ 10 MK) -- well known to Solar Physics -- have been
detected in about a dozen cool stars, mainly with HST/STIS. The UV
coronal forbidden lines are important because they can be observed
with velocity resolution of better than 15 km/s, whereas even the
state-of-the-art X-ray spectrometers on Chandra can manage only 300
km/s in the kilovolt band where lines of highly ionized iron more
commonly are found. The kinematic properties of hot coronal plasmas,
which are of great interest to theorists and modelers, thus only are
accessible in the UV at present. The bad news is that the UV coronal
forbidden lines are faint, and were captured only in very deep
observations with STIS. The good news is that 3rd-generation Cosmic
Origins Spectrograph, slated for installation in HST by SM4, in a mere
25 minute exposure with its G130M mode can duplicate the sensitivity
of a landmark 25-orbit STIS E140M observation of AD Leo, easily the
deepest such exposure of a late-type star so far. Our goal is to build
up understanding of the properties of Fe XII and Fe XXI in additional
objects beyond the current limited sample: how the lineshapes depend
on activity, whether large scale velocity shifts can be detected, and
whether the dynamical content of the lines can be inverted to map the
spatial morphology of the stellar corona (as in "Doppler Imaging'').
In other words, we want to bring to bear in the coronal venue all the
powerful tricks of spectroscopic remote sensing, well in advance of
the time that this will be possible exploiting the corona's native
X-ray radiation. The 1290-1430 band captured by side A of G130M also
contains a wide range of key plasma diagnostics that form at
temperatures from below 10, 000 K (neutral lines of CNO), to above
200, 000 K (semi-permitted O V 1371), including the important bright
multiplets of C II at 1335 and Si IV at 1400; yielding a diagnostic
gold mine for the subcoronal atmosphere. Because of the broad value of
the SNAP spectra, beyond the coronal iron project, we waive the normal
proprietary rights.

COS/FUV/COS/NUV 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/FUV/COS/NUV 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 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).

S/C/WFC3/IR 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).

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/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 11235

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies
in the Local Universe

At luminosities above 1011.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' (LIRGs) are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei (AGN) activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88
L_IR 1011.4 L_sun luminous infrared galaxies in the IRAS Revised
Bright Galaxy Sample (RBGS: i.e., 60 micron flux density 5.24 Jy).
This sample is ideal not only in its completeness and sample size, but
also in the proximity and brightness of the galaxies. The superb
sensitivity and resolution of NICMOS NIC2 on HST enables a unique
opportunity to study the detailed structure of the nuclear regions,
where dust obscuration may mask star clusters, AGN and additional
nuclei from optical view, with a resolution significantly higher than
possible with Spitzer IRAC. This survey thus provides a crucial
component to our study of the dynamics and evolution of IR galaxies
presently underway with Wide-Field, HST ACS/WFC and Spitzer IRAC
observations of these 88 galaxies. Imaging will be done with the F160W
filter (H-band) to examine as a function of both luminosity and merger
stage (i) the luminosity and distribution of embedded star clusters,
(ii) the presence of optically obscured AGN and nuclei, (iii) the
correlation between the distribution of 1.6 micron emission and the
mid-IR emission as detected by Spitzer IRAC, (iv) the evidence of bars
or bridges that may funnel fuel into the nuclear region, and (v) the
ages of star clusters for which photometry is available via ACS/WFC
observations. The NICMOS data, combined with the HST ACS, Spitzer, and
GALEX observations of this sample, will result in the most
comprehensive study of merging and interacting galaxies to date.

WFC3/IR 11700

Bright Galaxies at z7.5 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 z7.5 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 z7.5 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 z7.5 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 z7.5 candidates within
one month from the acquisition of each field.

WFC3/IR 11926

IR Zero Points

We will measure and monitor the zeropoints through the IR filters
using observations of the white dwarf standard stars, GD153, GD71 and
GD191B2B and the solar analog standard star, P330E. Data will be taken
monthly during Cycle 17. Observations of the star cluster, NGC 104,
are made twice to check color transformations. We expect an accuracy
of 2% in the wide filter zeropoints relative to the HST photometric
system, and 5% in the medium- and narrow-band filters.

WFC3/UVI 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/UVI 11650

Mutual Orbits, Colors, Masses, and Bulk Densities of 3 Cold Classical
Transneptunian Binaries

Many transneptunian objects (TNOs) have been found to be binary or
multiple systems. As in other astrophysical settings, trans?neptunian
binaries (TNBs) offer uniquely valuable information. Their mutual
orbits allow the direct determination of their system masses, perhaps
the most fundamental physical quantity of any astronomical object.
Their frequency of occurrence and dynamical characteristics provide
clues to formation conditions and evolution scenarios affecting both
the binaries and their single neighbors. Combining masses with sizes,
bulk densities can be measured. Densities constrain bulk composition
and internal structure, key clues to TNO origins and evolution over
time. Several TNB bulk densities have been determined, hinting at
interesting trends. But none of them belongs to the Cold Classical
sub-population, the one group of TNOs with demonstrably distinct
physical characteristics. Two top-priority Spitzer programs will soon
observe and measure the sizes of 3 Cold Classical TNBs. This proposal
seeks to determine the mutual orbits and thus masses of these systems,
enabling computation of their densities.

WFC3/UVI 11729

Photometric Metallicity Calibration with WFC3 Specialty Filters

The community has chosen to include several filters in the WFC3 filter
complement that have been designed to allow fairly precise estimates
of stellar metallicities, and many science programs are enabled by
this capability. Since these filters do not exactly match those used
for this purpose on the ground, however, the mapping of stellar colors
to stellar metallicities needs to be calibrated. We propose to achieve
this calibration through observations of five stellar clusters with
well known metallicities. We will calibrate several different filter
calibrations which will allow future users to determine what filter
combination best meets their science needs.

WFC3/UVI 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 biasBRand dark frames. A smaller set of
2Kx4K subarray biases are acquired at less frequent
intervalsBRthroughout the cycle to support subarray science
observations. The internals from this proposal,BRalong with those
from the anneal procedure (11909), will be used to generate the
necessary superbiasBRand superdark reference files for the
calibration pipeline (CDBS).


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:
none

COMPLETED OPS NOTES:
none

SCHEDULED SUCCESSFUL
FGS GSAcq 9 9
FGS REAcq 6 6
OBAD with Maneuver 4 4

SIGNIFICANT EVENTS:
none

 




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