Daily Report #5091

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 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.