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Daily Report #5056



 
 
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Old March 19th 10, 06:15 PM posted to sci.astro.hubble
Bassford, Lynn[_2_]
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Default Daily Report #5056

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5056

PERIOD COVERED: 5am March 18 - 5am March 19, 2010 (DOY 077/09:00z-078/09:00z)

OBSERVATIONS SCHEDULED

COS/NUV 11705

Physical Properties of Quasar Outflows: From BALs to Mini-BALs

Accretion disk outflows are important components of quasar
environments. They might play a major role in facilitating accretion,
regulating star formation in the host galaxies and distributing metals
to the surrounding gas. They reveal themselves most conspicuously via
broad absorption lines (BALs), but they appear even more frequently in
other guises such as the weaker and narrower "mini-BALs." How are
these diverse outflow features related? Are mini-BALs really just
"mini" versions of the BALs, or do they represent a fundamentally
different type of outflow, with different degrees of ionization,
column densities, mass loss rates, physical origins, etc?

We propose HST-COS spectroscopy to make the first quantitative
assessment of the outflow physical conditions across the full range of
weak/narrow mini-BALs to strong/broad BALs. Our strategy is to measure
key diagnostic lines (SVI, OVI, CIII, SIV, PV, etc.) at 930A - 1130A
(rest- frame) in a sample of 7 outflow quasars with known mini-BALs
through weak BALs. We will then 1) combine the COS data with
ground-based spectra of the same quasars to include more lines (CIV,
SiIV) at longer wavelengths, and 2) include in our analysis a nearly
identical UV/optical dataset obtained previously for a sample of
quasars with strong BALs. Our study of this combined dataset will be
an essential next step toward a more global understanding of quasar
outflows.

COS/NUV/FUV 11741

Probing Warm-Hot Intergalactic Gas at 0.5 z 1.3 with a Blind
Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems

Currently we can only account for half of the baryons (or less)
expected to be found in the nearby universe based on D/H and CMB
observations. This "missing baryons problem" is one of the
highest-priority challenges in observational extragalatic astronomy.
Cosmological simulations suggest that the baryons are hidden in
low-density, shock-heated intergalactic gas in the log T = 5 - 7
range, but intensive UV and X-ray surveys using O VI, O VII, and O
VIII absorption lines have not yet confirmed this prediction. We
propose to use COS to carry out a sensitive survey for Ne VIII and Mg
X absorption in the spectra of nine QSOs at z(QSO) 0.89. For the
three highest-redshift QSOs, we will also search for Si XII. This
survey will provide more robust constraints on the quantity of baryons
in warm-hot intergalactic gas at 0.5 z 1.3, and the data will
provide rich constraints on the metal enrichment, physical conditions,
and nature of a wide variety of QSO absorbers in addition to the
warm-hot systems. By comparing the results to other surveys at lower
redshifts (with STIS, FUSE, and from the COS GTO programs), the
project will also enable the first study of how these absorbers evolve
with redshift at z 1. By combining the program with follow-up galaxy
redshift surveys, we will also push the study of galaxy-absorber
relationships to higher redshifts, with an emphasis on the
distribution of the WHIM with respect to the large-scale matter
distribution of the universe.

NIC2/WFC3/IR 11548

Infrared Imaging of Protostars in the Orion A Cloud: The Role of
Environment in Star Formation

We propose NICMOS and WFC3/IR observations of a sample of 252
protostars identified in the Orion A cloud with the Spitzer Space
Telescope. These observations will image the scattered light escaping
the protostellar envelopes, providing information on the shapes of
outflow cavities, the inclinations of the protostars, and the overall
morphologies of the envelopes. In addition, we ask for Spitzer time to
obtain 55-95 micron spectra of 75 of the protostars. Combining these
new data with existing 3.6 to 70 micron photometry and forthcoming
5-40 micron spectra measured with the Spitzer Space Telescope, we will
determine the physical properties of the protostars such as envelope
density, luminosity, infall rate, and outflow cavity opening angle. By
examining how these properties vary with stellar density (i.e.
clusters vs. groups vs. isolation) and the properties of the
surrounding molecular cloud; we can directly measure how the
surrounding environment influences protostellar evolution, and
consequently, the formation of stars and planetary systems.
Ultimately, this data will guide the development of a theory of
protostellar evolution.

S/C 11639

Catching Accreting WDs Moving into Their Instability Strip(s)

Our past HST studies of the temperatures of 9 accreting, pulsating
white dwarfs in cataclysmic variables show that 3 are in the normal
instability strip for single white dwarfs, but the other 6 are much
hotter (15, 000-16, 500K). This dual strip has been proposed to be due
to mass differences in the white dwarfs related to evolutionary
history and driven by the ionization of different elements in their
respective driving regions. In 2007, GW Lib (the brightest and best
studied of the 6 hot accreting pulsators) and V455 And (the brightest
and best studied of the 3 cool accreting pulsators) underwent rare
large amplitude dwarf nova outbursts (known to heat the white dwarf)
and their pulsations disappeared. We propose COS observations to: a)
take advantage of the unprecedented opportunity to view the change in
pulsation modes due to cooling of the white dwarf envelope and b)
determine the masses of the white dwarfs to test the dual strip
theory. In addition, a nova that had its outburst 22 yrs ago has begun
non-radial pulsations as it returns to quiescence. We will use COS to
determine its temperature in relation to the instability strip for the
pulsating white dwarfs in dwarf novae.

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.

WFC3/ACS 11888

ACS Internal Flat Fields

The stability of the CCD flat fields will be monitored using the
calibration lamps and a sub-sample of the filter set. High signal
observations will be used to assess the stability of the
pixel-to-pixel flat field structure and to monitor the position of the
dust motes.

WFC3/IR 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still
largely an open problem in cosmology: how does the Universe evolve
from large linear scales dominated by dark matter to the highly
non-linear scales of galaxies, where baryons and dark matter both play
important, interacting, roles? To understand the complex physical
processes involved in their formation scenario, and why they have the
tight scaling relations that we observe today (e.g. the Fundamental
Plane), it is critically important not only to understand their
stellar structure, but also their dark-matter distribution from the
smallest to the largest scales. Over the last three years the SLACS
collaboration has developed a toolbox to tackle these issues in a
unique and encompassing way by combining new non-parametric strong
lensing techniques, stellar dynamics, and most recently weak
gravitational lensing, with high-quality Hubble Space Telescope
imaging and VLT/Keck spectroscopic data of early-type lens systems.
This allows us to break degeneracies that are inherent to each of
these techniques separately and probe the mass structure of early-type
galaxies from 0.1 to 100 effective radii. The large dynamic range to
which lensing is sensitive allows us both to probe the clumpy
substructure of these galaxies, as well as their low-density outer
haloes. These methods have convincingly been demonstrated, by our
team, using smaller pilot-samples of SLACS lens systems with HST data.
In this proposal, we request observing time with WFC3 and NICMOS to
observe 53 strong lens systems from SLACS, to obtain complete
multi-color imaging for each system. This would bring the total number
of SLACS lens systems to 87 with completed HST imaging and effectively
doubles the known number of galaxy-scale strong lenses. The deep HST
images enable us to fully exploit our new techniques, beat down
low-number statistics, and probe the structure and evolution of early-
type galaxies, not only with a uniform data-set an order of magnitude
larger than what is available now, but also with a fully-coherent and
self-consistent methodological approach!

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 11912

UVIS Internal Flats

This proposal will be used to assess the stability of the flat field
structure for the UVIS detector throughout the 15 months of Cycle 17.
The data will be used to generate on-orbit updates for the delta-flat
field reference files used in the WFC3 calibration pipeline, if
significant changes in the flat structure are seen.

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.

WFC3/UVIS/IR 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond
the current redshift frontier. Here we propose a pure parallel program
using this new instrument to search for Lyman-break galaxies at
6.5z8.8 and to probe the epoch of reionization, a hallmark event in
the history of the early universe. We request 200 orbits, spreading
over 30 ~ 50 high Galactic latitude visits (|b|20deg) that last for 4
orbits and longer, resulting a total survey area of about 140~230
square arcminute. Based on our understanding of the new HST parallel
observation scheduling process, we believe that the total number of
long-duration pure parallel visits in Cycle 17 should be sufficient to
accommodate our program. We waive all proprietary rights to our data,
and will also make the enhanced data products public in a timely
manner.

(1) We will use both the UVIS and the IR channels, and do not need to
seek optical data from elsewhere.

(2) Our program will likely triple the size of the probable candidate
samples at z~7 and z~8, and will complement other targeted programs
aiming at the similar redshift range.

(3) Being a pure parallel program, our survey will only make very
limited demand on the scarce HST resources. More importantly, as the
pure parallel pointings will be at random sight-lines, our program
will be least affected by the bias due to the large scale structure
("cosmic variance").

(4) We aim at the most luminous LBG population, and will address the
bright-end of the luminosity function at z~8 and z~7. We will
constrain the value of L* in particular, which is critical for
understanding the star formation process and the stellar mass assembly
history in the first few hundred million years of the universe.

(5) The candidates from our survey, most of which will be the
brightest ones that any surveys would be able to find, will have the
best chance to be spectroscopically confirmed at the current 8-10m
telescopes.

(6) We will also find a large number of extremely red, old galaxies at
intermediate redshifts, and the fine spatial resolution offered by the
WFC3 will enable us constrain their formation history based on the
study of their morphology, and hence shed light on their connection to
the very early galaxies in the universe.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

#12224 Negative Acquisition During Coho Support @076/14:57z

HST experienced its first negative acquisition since the switch on DOY
074 to COHO on MAT2. Commanding was sent to reacquire return and
forward telemetry, resulting in zero science loss.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 7 7
FGS REAcq 9 9
OBAD with Maneuver 7 7

SIGNIFICANT EVENTS: (None)
 




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