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Daily Report #5096



 
 
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Old May 14th 10, 04:13 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report #5096

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5096

PERIOD COVERED: 5am May 13 - 5am May 14, 2010 (DOY 133/09:00z-134/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12276 - GSAcq(2,0,2) scheduled at 133/09:37:03z failed to RGA control
due to scan step limit exceeded on FGS 2.

Observations affected: Astrometry, Proposal ID#11704.

12278 - GSAcq(2,0,2) scheduled at 133/11:12:51z failed to RGA Hold
(gyro control) due to scan step limit exceeded on FGS-2.

Observations affected: Astrometry, Proposal ID#11704

12280 - Following successful REAcq(1,2,1), a Loss of Lock occurred
while guiding with FGS-1 and FGS-2 at 134/08:23:29z. The REAcq
continued guiding until Term EXP at 134/08:43:02z.

Observation possibly affected: WFC3 159 Prop#11595

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSAcq 8 6
FGS REAcq 7 7
OBAD with Maneuver 7 7
LOSS of LOCK 134/0823z

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 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).

FGS 11704

The Ages of Globular Clusters and the Population II Distance Scale

Globular clusters are the oldest objects in the universe whose age can
be accurately determined. The dominant error in globular cluster age
determinations is the uncertain Population II distance scale. We
propose to use FGS 1r to obtain parallaxes with an accuracy of 0.2
milliarcsecond for 9 main sequence stars with [Fe/H] -1.5. This will
determine the absolute magnitude of these stars with accuracies of
0.04 to 0.06mag. This data will be used to determine the distance to
24 metal-poor globular clusters using main sequence fitting. These
distances (with errors of 0.05 mag) will be used to determine the ages
of globular clusters using the luminosity of the subgiant branch as an
age indicator. This will yield absolute ages with an accuracy 5%,
about a factor of two improvement over current estimates. Coupled with
existing parallaxes for more metal-rich stars, we will be able to
accurately determine the age for globular clusters over a wide range
of metallicities in order to study the early formation history of the
Milky Way and provide an independent estimate of the age of the
universe.

The Hipparcos database contains only 1 star with [Fe/H] -1.4 and an
absolute magnitude error less than 0.18 mag which is suitable for use
in main sequence fitting. Previous attempts at main sequence fitting
to metal-poor globular clusters have had to rely on theoretical
calibrations of the color of the main sequence. Our HST parallax
program will remove this source of possible systematic error and yield
distances to metal-poor globular clusters which are significantly more
accurate than possible with the current parallax data. The HST
parallax data will have errors which are 10 times smaller than the
current parallax data. Using the HST parallaxes, we will obtain main
sequence fitting distances to 11 globular clusters which contain over
500 RR Lyrae stars. This will allow us to calibrate the absolute
magnitude of RR Lyrae stars, a commonly used Population II distance
indicator.

STIS/CCD 11682

An HST/STIS spectroscopic investigation: is Kelu-1 AB a brown dwarf -
brown dwarf binary?

We propose to obtain resolved HST/STIS spectroscopy for the benchmark
binary brown dwarf Kelu-1 AB. Dynamical masses are being obtained by
monitoring the orbital motion using ground-based telescopes with
adaptive optics. The main goal of this program is to study the Li I
resonance line at 670.8 nm and investigate if only one or even both
components bear lithium. This observation will be compared to model
predictions of lithium depletion as a function of age and mass, and
including our model independent ground-based mass estimations, hence
will provide an observational test to the theory of substellar
objects. Spin-offs will be the measurement of the strength of H-alpha
emission, an indicator of chromospheric activity in cool atmospheres,
and comparing the shape of the optical continuum with model spectra
with different dust opacities. Thus our program will be an important
step towards the understanding of brown dwarf atmospheres and to
establish precise models for their formation and evolution.

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.

WFC3/IR 11696

Infrared Survey of Star Formation Across Cosmic Time

We propose to use the unique power of WFC3 slitless spectroscopy to
measure the evolution of cosmic star formation from the end of the
reionization epoch at z6 to the close of the galaxy-building era at
z~0.3.Pure parallel observations with the grisms have proven to be
efficient for identifying line emission from galaxies across a broad
range of redshifts. The G102 grism on WFC3 was designed to extend this
capability to search for Ly-alpha emission from the first galaxies.
Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will
observe about 40 deep (4-5 orbit) fields with the combination of G102
and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.

Our primary science goals at the highest redshifts a (1) Detect
Lya in ~100 galaxies with z5.6 and measure the evolution of the Lya
luminosity function, independent of of cosmic variance; 2) Determine
the connection between emission-line selected and continuum-break
selected galaxies at these high redshifts, and 3) Search for the
proposed signature of neutral hydrogen absorption at re-ionization. At
intermediate redshifts we will (4) Detect more than 1000 galaxies in
Halpha at 0.5z1.8 to measure the evolution of the
extinction-corrected star formation density across the peak epoch of
star formation. This is over an order-of-magnitude improvement in the
current statistics, from the NICMOS Parallel grism survey. (5) Trace
``cosmic downsizing" from 0.5z2.2; and (6) Estimate the evolution in
reddening and metallicty in star-forming galaxies and measure the
evolution of the Seyfert population. For hundreds of spectra we will
be able to measure one or even two line pair ratios -- in particular,
the Balmer decrement and [OII]/[OIII] are sensitive to gas reddening
and metallicity. As a bonus, the G102 grism offers the possiblity of
detecting Lya emission at z=7-8.8.

To identify single-line Lya emitters, we will exploit the wide
0.8--1.9um wavelength coverage of the combined G102+G141 spectra. All
[OII] and [OIII] interlopers detected in G102 will be reliably
separated from true LAEs by the detection of at least one strong line
in the G141 spectrum, without the need for any ancillary data. We
waive all proprietary rights to our data and will make high-level data
products available through the ST/ECF.

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 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF),
and calibrate the SBF distance method, in the F110W and F160W filters
of the Wide Field Camera 3 IR channel. Because of the very high
throughput of F110W and the good match of F160W to the standard H
band, we anticipate that both of these filters will be popular choices
for galaxy observations with WFC3/IR. The SBF signal is typically an
order of magnitude brighter in the near-IR than in the optical, and
the characterisitics (sensitivity, FOV, cosmetics) of the WFC3/IR
channel will be enormously more efficient for SBF measurements than
previously available near-IR cameras. As a result, our proposed SBF
calibration will allow accurate distance derivation whenever an
early-type or bulge-dominated galaxy is observed out to a distance of
150 Mpc or more (i.e., out to the Hubble flow) in the calibrated
passbands. For individual galaxy observations, an accurate distance is
useful for establishing absolute luminosities, black hole masses,
linear sizes, etc. Eventually, once a large number of galaxies have
been observed across the sky with WFC3/IR, this SBF calibration will
enable accurate mapping of the total mass density distribution in the
local universe using the data available in the HST archive. The
proposed observations will have additional important scientific value;
in particular, we highlight their usefulness for understanding the
nature of multimodal globular cluster color distributions in giant
elliptical galaxies.

WFC3/UVI 11595

Turning out the Light: A WFC3 Program to Image z2 Damped Lyman Alpha
Systems

We propose to directly image the star-forming regions of z2 damped
Lya systems (DLAs) using the WFC3/UVIS camera on the Hubble Space
Telescope. In contrast to all previous attempts to detect the galaxies
giving rise to high redshift DLAs, we will use a novel technique that
completely removes the glare of the background quasar. Specifically,
we will target quasar sightlines with multiple DLAs and use the higher
redshift DLA as a ``blocking filter'' (via Lyman limit absorption) to
eliminate all FUV emission from the quasar. This will allow us to
carry out a deep search for FUV emission from the lower redshift DLA,
shortward of the Lyman limit of the higher redshift absorber. The
unique filter set and high spatial resolution afforded by WFC3/UVIS
will then enable us to directly image the lower redshift DLA and thus
estimate its size, star-formation rate and impact parameter from the
QSO sightline. We propose to observe a sample of 20 sightlines,
selected primarily from the SDSS database, requiring a total of 40 HST
orbits. The observations will allow us to determine the first FUV
luminosity function of high redshift DLA galaxies and to correlate the
DLA galaxy properties with the ISM characteristics inferred from
standard absorption-line analysis to significantly improve our
understanding of the general DLA population.

WFC3/UVI 11605

Obtaining the Missing Links in the Test of Very Low Mass Evolutionary
Models with HST

We are proposing for spatially resolved ACS+HRC observations of 11
very low mass binaries spanning late-M, L and T spectral types in
order to obtain precise effective temperature measurements for each
component. All of our targets are part of a program in which we are
measuring dynamical masses of very low-mass binaries to an
unprecedented precision of 10% (or better). However, without precise
temperature measurements, the full scientific value of these mass
measurements cannot be realized. Together, mass and temperature
measurements will allow us to distinguish between brown dwarf
evolutionary models that make different assumptions about the interior
and atmospheric structure of these ultra-cool objects. While dynamical
masses can be obtained from the ground in the near-IR, obtaining
precise temperatures require access to optical data which, for these
sub-arcsecond binaries, can only be obtained from space with Hubble.

WFC3/UVI 11643

A Timeline for Early-Type Galaxy Formation: Mapping the Evolution of
Star Formation, Globular Clusters, Dust, and Black Holes

While considerable effort has been devoted to statistical studies of
the origin of the red sequence of galaxies, there has been relatively
little direct exploration of galaxies transforming from late to early
types. Such galaxies are identified by their post-starburst spectra,
bulge-dominated, tidally-disturbed morphologies, and current lack of
gas. We are constructing the first detailed timeline of their
evolution onto the red sequence, pinpointing when star formation ends,
nuclear activity ceases, globular clusters form, and the bulk of the
merging progenitors' dust disappears. Here we propose to obtain HST
and Chandra imaging of nine galaxies, whose wide range of
post-starburst ages we have precisely dated with a new UV-optical
technique and for which we were awarded Spitzer time. We will address
1) whether the black hole-bulge mass relation arises from nuclear
feedback, 2) whether the bimodality of globular cluster colors is due
to young clusters produced in galaxy mergers, and 3) what happens to
the dust when late types merge to form an early type.

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).


 




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