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 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.