HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5129
PERIOD
COVERED: 5am June 30 - 5am July 1, 2010 (DOY 181/09:00z-182/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12319
- REAcq(1,2,1) scheduled at 181/19:43:29z - 19:47:55z required three
attempts to achieve FL-DV on FGS-2. The acquisition was
successful.
Observations possibly affected: ACS 34, 35, Proposal ID#11669.
FOR
DOY 172
12317
- GSAcq(2,1,1) at 172/14:53:57z required two attempts to achieve
CT-DV on FGS2. The acquisition was successful.
FOR
DOY 178
12318
- GSAcq(2,1,1) at 178/21:01:47z required two attempts to maintain lock.
The second attempt was successful.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
7
7
FGS
REAcq
7
7
OBAD
with Maneuver 3
3
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
ACS/WFC
11996
CCD
Daily Monitor (Part 3)
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 308 orbits (19.25 weeks) from 21 June 2010 to 1 November
2010.
ACS/WFC3
11669
The
Origins of Short Gamma-Ray Bursts
During
the past decade extraordinary progress has been made in
determining
the origin of long- duration gamma-ray bursts. It has been
conclusively
shown that these objects derive from the deaths of massive
stars.
Nonetheless, the origin of their observational cousins,
short-duration
gamma-ray bursts (SGRBs) remains a mystery. While SGRBs
are
widely thought to result from the inspiral of compact binaries, this
is
a conjecture. SGRBs have been found in elliptical galaxies, Abell
Clusters,
star-forming dwarfs and even an edge-on spiral. Whether they
primarily
result from an old population, a young population, or rapid
evolution
of binaries in globular clusters remains open.
Here
we propose to employ two related sets of observations which may
dramatically
advance our understanding of short bursts. The first is a
variant
of a technique that we pioneered and used to great effect in
elucidating
the origins of long-duration bursts. We will examine a
statistical
sample of hosts and measure the degree to which SGRB
locations
trace the red or blue light of their hosts, and thus old or
young
stellar populations. This will allow us to study the demographics
of
the SGRB population in a manner largely free of the distance
dependent
selection effects which have so far bedeviled this field. In
the
second line of attack we will use two targets of opportunity to
obtain
extremely precise positions of up to two nearby bursts -- one on
a
star-forming galaxy and the other on a elliptical. Observation of the
star-formation
galaxy could link at least some bursts directly to a
young
population; however, a discovery in later images of a globular
cluster
at the site of the explosion in an elliptical would provide
revolutionary
evidence that SGRBs are formed from compact binaries.
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/IR
11597
Spectroscopy
of IR-Selected Galaxy Clusters at 1 < z < 1.5
We
propose to obtain WFC3 G141 and G102 slitless spectroscopy of galaxy
clusters
at 1 < z < 1.5 that were selected from the IRAC survey of the
Bootes
NDWFS field. Our IRAC survey contains the largest sample of
spectroscopically
confirmed clusters at z > 1. The WFC3 grism data will
measure
H-alpha to determine SFR, and fit models to the low resolution
continua
to determine stellar population histories for the brighter
cluster
members, and redshifts for the red galaxies too faint for
ground-based
optical spectroscopy.
WFC3/UV/ACS/WFC
11739
Multiple
Stellar Generations in the Unique Globular Clusters NGC 6388
and
NGC 6441
Over
the last few years HST observations have resulted in one of the
most
exciting and unexpected developments in stellar population studies:
the
discovery of multiple generations of stars in several globular
clusters.
The finding of multiple main sequences in the massive clusters
NGC
2808 and Omega Centauri, and multiple subgiant branches in NGC 1851,
M54,
and NGC 6388 has challenged the long-held paradigm that globular
clusters
are simple stellar populations. Even more surprising, given the
spectroscopic
and photometric constraints, the only viable explanation
for
the main sequence splitting appears to be Helium enrichment, up to
an
astonishingly high Y=0.4. The conditions under which certain
globulars
experience the formation of multiple stellar generations
remain
mysterious, and even more so the helium-enrichment phenomenon.
Such
an enrichment has important implications for chemical-enrichment,
star-formation,
and stellar-evolution scenarios, in star clusters and
likely
elsewhere. To properly constrain the multiple main sequence
phenomenon,
it is important to determine its extent among GCs: is it
limited
to Omega Cen and NGC2808, or is it more common? We propose deep
WFC3
optical/IR imaging of NGC 6388 and 6441, the two globular clusters
that
are most likely to host multiple, helium-enriched populations. Our
simulations
of WFC3 performance suggest that we will be able to detect
even
the main sequence splittings caused by small He differences (Delta
Y
<0.03).
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
11911
UVIS
L-Flats and Geometric Distortion
Multiple
pointing observations of the globular cluster Omega Centauri
(NGC
5139) will be used to measure the filter-dependent low frequency
flat
field (L-flat) corrections and stability for a key set of 10
broadband
filters used by GO programs. The selected filters are F225W,
F275W,
F336W, F390W, F438W, F555W, F606W, F775W, F814W and F850LP. By
measuring
relative changes in brightness of a star over different
portions
of the detector, we will determine local variations in the UVIS
detector
response.
The
broad wavelength range covered by these observations will allow us
to
derive the L-flat correction for the remaining wide, medium and
narrow-band
UVIS filters. The same data will also be used to determine
and
correct the geometric distortion that affects UVIS data. The broad
wavelength
range covered by these observations will allow us to measure
the
geometric distortion dependence with wavelength and filters and to
provide
the most appropriate correction over the entire wavelength range
provided
by UVIS.
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 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.