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Daily Report #5095



 
 
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Old May 13th 10, 04:32 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5095

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5095

PERIOD COVERED: 5am May 12 - 5am May 13, 2010 (DOY 132/09:00z-133/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12274 - REAcq(1,2,1) scheduled at 132/17:39:15z initially received a
stop flag indication on FGS-1 during acquisition walkdown. The
acquisition was finally successful.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 4 4
FGS REAcq 11 11
OBAD with Maneuver 3 3

SIGNIFICANT EVENTS: (None)





OBSERVATIONS SCHEDULED

ACS/WFC 11995

CCD Daily Monitor (Part 2)

This program comprises basic tests for measuring the read noise and
dark current of the ACS WFC and for tracking the growth of hot pixels.
The recorded frames are used to create bias and dark reference images
for science data reduction and calibration. This program will be
executed four days per week (Mon, Wed, Fri, Sun) for the duration of
Cycle 17. To facilitate scheduling, this program is split into three
proposals. This proposal covers 320 orbits (20 weeks) from 1 February
2010 to 20 June 2010.

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.

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/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/UV/IR 11664

The WFC3 Galactic Bulge Treasury Program: Populations, Formation
History, and Planets

Exploiting the full power of the Wide Field Camera 3 (WFC3), we
propose deep panchromatic imaging of four fields in the Galactic
bulge. These data will enable a sensitive dissection of its stellar
populations, using a new set of reddening-free photometric indices we
have constructed from broad-band filters across UV, optical, and
near-IR wavelengths. These indices will provide accurate temperatures
and metallicities for hundreds of thousands of individual bulge stars.
Proper motions of these stars derived from multi-epoch observations
will allow separation of pure bulge samples from foreground disk
contamination. Our catalogs of proper motions and panchromatic
photometry will support a wide range of bulge studies.

Using these photometric and astrometric tools, we will reconstruct the
detailed star-formation history as a function of position within the
bulge, and thus differentiate between rapid- and extended-formation
scenarios. We will also measure the dependence of the stellar mass
function on metallicity, revealing how the characteristic mass of star
formation varies with chemistry. Our sample of bulge stars with
accurate metallicities will include 12 candidate hosts of extrasolar
planets. Planet frequency is correlated with metallicity in the solar
neighborhood; our measurements will extend this knowledge to a remote
environment with a very distinct chemistry.

Our proposal also includes observations of six well-studied globular
and open star clusters; these observations will serve to calibrate our
photometric indices, provide empirical population templates, and
transform the theoretical isochrone libraries into the WFC3 filter
system. Besides enabling our own program, these products will provide
powerful new tools for a host of other stellar-population
investigations with HST/WFC3. We will deliver all of the products from
this Treasury Program to the community in a timely fashion.

WFC3/UVIS 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.8 z 2.5, using WFC3 and the G280 grism. This
proposal intends to complete an approved Cycle 15 SNAP program
(10878), which was cut short due to the ACS failure. We have selected
64 quasars at 2.3 z 2.6 from the Sloan Digital Sky Survey
Spectroscopic Quasar Sample, for which no BAL signature is found at
the QSO redshift and no strong metal absorption lines are present at z
2.3 along the lines of sight. The survey has three main

observational goals. First, we will determine the redshift frequency
dn/dz of the LLS over the column density range 16.0 log(NHI) 20.3
cm^-2. Second, we will measure the column density frequency
distribution f(N) for the partial Lyman limit systems (PLLS) over the
column density range 16.0 log(NHI) 17.5 cm^-2. Third, we will
identify those sightlines which could provide a measurement of the
primordial D/H ratio. By carrying out this survey, we can also help
place meaningful constraints on two key quantities of cosmological
relevance. First, we will estimate the amount of metals in the LLS
using the f(N), and ground based observations of metal line
transitions. Second, by determining f(N) of the PLLS, we can constrain
the amplitude of the ionizing UV background at z~2 to a greater
precision. This survey is ideal for a snapshot observing program,
because the on-object integration times are all well below 30 minutes,
and follow-up observations from the ground require minimal telescope
time due to the QSO sample being bright.

WFC3/UVIS 11650

Mutual Orbits, Colors, Masses, and Bulk Densities of 3 Cold Classical
Trans-Neptunian Binaries

Many Trans-Neptunian 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/UVIS 11697

Proper Motion Survey of Classical and SDSS Local Group Dwarf Galaxies

Using the superior resolution of HST, we propose to continue our
proper motion survey of Galactic dwarf galaxies. The target galaxies
include one classical dwarf, Leo II, and six that were recently
identified in the Sloan Digital Sky Survey data: Bootes I, Canes
Venatici I, Canes Venatici II, Coma Berenices, Leo IV, and Ursa Major
II. We will observe a total of 16 fields, each centered on a
spectroscopically-confirmed QSO. Using QSOs as standards of rest in
measuring absolute proper motions has proven to be the most accurate
and most efficient method. HST is our only option to quickly determine
the space motions of the SDSS dwarfs because suitable ground-based
imaging is only a few years old and such data need several decades to
produce a proper motion. The two most distant galaxies in our sample
will require time baselines of four years to achieve our goal of a
30-50 km/s uncertainty in the tangential velocity; given this and the
finite lifetime of HST, it is imperative that first-epoch observations
be taken in this cycle. The SDSS dwarfs have dramatically lower
surface brightnesses and luminosities than the classical dwarfs.
Proper motions are crucial for determining orbits of the galaxies and
knowing the orbits will allow us to test theories for the formation
and evolution of these galaxies and, more generally, for the formation
of the Local Group.

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/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.

 




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