Notice:
Due to the conversion of some ACS WFC or HRC observations into
WFPC2,
or NICMOS observations after the loss of ACS CCD science
capability
in January, there may be an occasional discrepancy between a
proposal's
listed (and correct) instrument usage and the abstract that
follows
it.
HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4483
PERIOD
COVERED: UT November 05, 2007 (DOY 309)
OBSERVATIONS
SCHEDULED
ACS/SBC
11215
New
Sightlines for the Study of Intergalactic Helium: Dozens of
High-Confidence,
UV- Bright Quasars from SDSS/GALEX
The
reionization of IGM helium is thought to have occurred at redshifts
of
z=3 to 4. Detailed study of HeII Lyman-alpha absorption toward a
handful
of QSOs at 2.7<z<3.3 demonstrated the high potential of such IGM
probes,
but the critically small sample size limits confidence in
cosmological
inferences. The requisite unobscured sightlines to high-z
are
extremely rare, but SDSS provides 5800, z>3.1 QSOs potentially
suitable
for HeII studies. We've cross-correlated SDSS quasars with
GALEX
UV sources to obtain dozens of new, high confidence, candidate
sightlines
{z=3.1-4.9} potentially useful for detailed HeII studies with
HST.
We propose brief, 2-orbit reconnaissance ACS SBC prism exposures
toward
each of the best dozen new quasars, to definitively verify UV
flux
down to HeII. Our combined SDSS/GALEX selection insures a high
confirmation
rate, as the quasars are already known to be UV bright in
GALEX.
Our program will provide a statistical sample of HeII sightlines
extending
to high redshift, enabling future long exposure follow-up
spectra
with the SBC prism, or superb quality COS or STIS spectra after
SM4.
Stacks of our prism spectra will also directly yield ensemble
information.
Ultimately, the new sightlines will enable confident
measures
of the spectrum and evolution of the ionizing background, the
evolution
of HeII opacity, the epoch of helium reionization, and the
density
of IGM baryons.
WFPC2
11024
WFPC2
CYCLE 15 INTERNAL MONITOR
This
calibration proposal is the Cycle 15 routine internal monitor for
WFPC2,
to be run weekly to monitor the health of the cameras. A variety
of
internal exposures are obtained in order to provide a monitor of the
integrity
of the CCD camera electronics in both bays {both gain 7 and
gain
15 -- to test stability of gains and bias levels}, a test for
quantum
efficiency in the CCDs, and a monitor for possible buildup of
contaminants
on the CCD windows. These also provide raw data for
generating
annual super-bias reference files for the calibration
pipeline.
FGS
11212
Filling
the Period Gap for Massive Binaries
The
current census of binaries among the massive O-type stars is
seriously
incomplete for systems in the period range from years to
millennia
because the radial velocity variations are too small and the
angular
separations too close for easy detection. Here we propose to
discover
binaries in this observational gap through a Faint Guidance
Sensor
SNAP survey of relatively bright targets listed in the Galactic O
Star
Catalog. Our primary goal is to determine the binary frequency
among
those in the cluster/association, field, and runaway groups. The
results
will help us assess the role of binaries in massive star
formation
and in the processes that lead to the ejection of massive
stars
from their natal clusters. The program will also lead to the
identification
of new, close binaries that will be targets of long term
spectroscopic
and high angular resolution observations to determine
their
masses and distances. The results will also be important for the
interpretation
of the spectra of suspected and newly identified binary
and
multiple systems.
NIC1/NIC2/NIC3
11060
NICMOS
Photometric Stability Monitoring
This
NICMOS calibration proposal carries out photometric monitoring
observations
during Cycle 15. The format is the same as the Cycle 14
version
of the program {10725}, but a few modifications were made with
respect
to the Cycle 12 program 9995 and Cycle 13 program 10381.
Provisions
had to be made to adopt to 2-gyro mode {G191B2B was added as
extra
target to provide target visibility through most of the year}.
Where
before 4 or 7 dithers were made in a filter before we moved to the
next
filter, now we observe all filters at one position before moving to
the
next dither position. While the previous method was chosen to
minimize
the effect of persistence, we now realize that persistence may
be connected
to charge trapping and by moving through the filter such
that
the count rate increases, we reach equilibrium more quickly between
charge
being trapped and released. We have also increased exposure times
where
possible to reduce the charge trapping non- linearity effects.
NIC1/NIC2/NIC3
8794
NICMOS
Post-SAA calibration - CR Persistence Part 5
A
new procedure proposed to alleviate the CR-persistence problem of
NICMOS.
Dark frames will be obtained immediately upon exiting the SAA
contour
23, and every time a NICMOS exposure is scheduled within 50
minutes
of coming out of the SAA. The darks will be obtained in parallel
in
all three NICMOS Cameras. The POST-SAA darks will be non- standard
reference
files available to users with a USEAFTER date/time mark. The
keyword
'USEAFTER=date/time' will also be added to the header of each
POST-SAA
DARK frame. The keyword must be populated with the time, in
addition
to the date, because HST crosses the SAA ~8 times per day so
each
POST-SAA DARK will need to have the appropriate time specified, for
users
to identify the ones they need. Both the raw and processed images
will
be archived as POST-SAA DARKs. Generally we expect that all NICMOS
science/calibration
observations started within 50 minutes of leaving an
SAA
will need such maps to remove the CR persistence from the science
images.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
NIC2
11341
Lower
Luminosity AGNs at Cosmologically Interesting Redshifts: SEDs and
Accretion
Rates of z~0.36 Seyferts
We
propose a multiwavelength campaign to constrain the SEDs of Seyferts
at
z~0.36. This epoch, corresponding to a look back time of 4 Gyrs, is
cosmologically
interesting for studies of the coeval development of
black
holes and their host galaxy bulges. Our sample, comprising 24
Seyferts,
has unprecedented high quality Keck spectroscopy and HST
imaging
already invested to extract host galaxy bulge properties,
estimate
black hole masses, and separate nuclear and host optical
luminosities.
To supplement and extend this successful program, we
request
93 ks of Chandra time (to measure the shape and power of the
AGN-only
X-ray continuum), 11 hrs each of Spitzer and Gemini (to
constrain
the dust temperature), and 7 orbits of HST (to determine the
nuclear
luminosity for the final 7 objects).
NIC3/WFPC2
10921
Tangential
Velocities of Objects in the Orion Nebula and Locating the
Embedded
Outflow Sources.
The
Orion Nebula is arguably the Rosetta Stone for studying a very young
star
cluster and how the radiation and outflowing plasma from its stars
interact
with ambient material. It has been the subject of numerous HST
imaging
studies, which means that there is good opportunity for
determining
tangential velocities by obtaining second epoch images
during
Cycle 15, which may be the last cycle for which the WFPC2 is
available.
These velocities in the plane-of-the-sky will allow us to
determine
the patterns of outflow from micro-jets smaller than the Solar
System
to jet driven shocks more than a parsec from their sources.
Combined
with radial velocities, we'll obtain spatial velocities, which
are
critical to determining where the embedded sources are located that
produce
the numerous HH objects coming from the Orion-S and BN-KL
regions.
We'll also be able to determine the physics that is operating
in
the LL Ori type of outflows {where a bipolar jet is being distorted
by
a slow wind coming from the nebula}. We will also be able to search
for
runaway stars caused by the disintegration of young multiple-star
systems.
All of this is possible because the long-time base of the WFPC2
and
ACS observations allow a new level of astrometric precision to be
obtained
and to be done efficiently by making coordinated parallel
observations
with all images.
WFPC2
10900
Optical
polarimetry of PSR B0540-69 and its synchrotron nebula.
Polarization
measurements of pulsars and of their synchrotron nebulae
are
uniquely able to provide deep insights into the highly magnetized
relativistic
environment of young rotating neutron stars. Apart from the
radio
band, pulsar polarization is best measured in the optical, for the
rare
cases of detectable optical emission. One of the brightest pulsars
together
with Crab {PSR B0531+21} and Vela {PSR B0833-45}, for which
optical
polarization measurements support the newly developed two-pole
caustic
model {TPC}, is PSR B0540-69 in the Large Magellanic Clouds,
often
referred as the Crab Twin for their overall similarities in both
age
and energetics. Together with the Crab, PSR B0540-69 is also the
only
pulsar embedded in a synchrotron nebula visible at optical
wavelengths.
We plan to observe PSR B0540-69 and its compact nebula {4
arcsec
diameter} with the Advanced Camera for Surveys {ACS} and the Wide
Field
Channel {WFC} detector using UV and visual polarization filters.
Thanks
to the superb angular resolution of ACS, these observations will
allow
us to spectacularly resolve the pulsar from its nebular
background,
providing the first firm measure of the pulsar polarization
which
will be crucial to assess, on a broader sample, the validity of
the
TPC model with respect to other pulsars magnetosphere models. These
observations
will also provide the first detailed polarization map of
the
nebula, including the jet and the torus seen in our previous WFPC2
images.
WFPC2
10919
Eclipsing
Binaries in the Local Group: II - Calibration of the Zeropoint
of
the Cosmic Distance Scale and Fundamental Properties of Stars in M33
(uses
NIC3)
The
Great Spiral Galaxy in Triangulum {M33} is potentially a crucial
calibrator
for the Cosmic Distance Scale, and thus for determining the
age
and evolution of the Universe. M33 is viewed face-on, has a simple
geometry,
large and diverse stellar populations, and morphologies
similar
to our Galaxy and other more distant galaxies used for distance
determinations.
Yet currently the M33 distance {d ~ 830 +/- 110 kpc}
still
has measurement dispersions of 10-15%. We have demonstrated, in
our
work on the LMC and M31 distances, that double-line eclipsing
binaries
can serve as excellent "standard candles." Distances derived
from
eclipsing binaries are basically geometric and essentially free
from
many assumptions and uncertainties that plague other less direct
methods,
such as metallicity differences and calibration zeropoints. The
absolute
radii of the component stars of eclipsing binaries can be
determined
to better than a few percent from the time- tested analyses
of
their light and radial velocity curves. With accurate determinations
of
radii, temperatures, and ISM absorption it is possible to determine
reliable
distances. We are extending our program of using eclipsing
binaries
as standard candles to determine an accurate distance to M33.
As
a first step, we are proposing to carry out HST/ACS spectrophotometry
of
a well suited ~19th mag ~O7 + ~O7 eclipsing binary system in M33 that
has
been previously observed from the ground. HST/ACS prism/grism
low-resolution
spectrophotometry {118-850 nm} is the only missing key
element
of this program and is used to determine more reliable values
for
T_eff, [Fe/H], and ISM extinction. These quantities, when combined
with
the results from existing light and radial velocity curves for the
target,
yield the stellar masses, radii, luminosities and, importantly,
the
distance. The proposed HST/ACS program can be carried out
effectively
with only 1 HST orbit. Based on our previous experience, we
expect
to reduce the uncertainty of the M33 distance to better than
5-7%,
thereby leading to a firmer calibration of the Cosmic Distance
Scale
and the zeropoint of the Hubble Constant {Ho}.
WFPC2
11028
WFPC2
Cycle 15 UV Earth Flats
Monitor
flat field stability. This proposal obtains sequences of earth
streak
flats to improve the quality of pipeline flat fields for the
WFPC2
UV filter set. These Earth flats will complement the UV earth flat
data
obtained during cycles 8-14.
WFPC2
11070
WFPC2
CYCLE 15 Standard Darks - part II
This
dark calibration program obtains dark frames every week in order to
provide
data for the ongoing calibration of the CCD dark current rate,
and
to monitor and characterize the evolution of hot pixels. Over an
extended
period these data will also provide a monitor of radiation
damage
to the CCDs.
WFPC2
11103
A
Snapshot Survey of The Most Massive Clusters of Galaxies
We
propose the continuation of our highly successful SNAPshot survey of
a
sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7.
As demonstrated by the 25 snapshots obtained so far in Cycle14
and
Cycle15 these systems frequently exhibit strong gravitational
lensing
as well as spectacular examples of violent galaxy interactions.
The
proposed observations will provide important constraints on the
cluster
mass distributions, the physical nature of galaxy-galaxy and
galaxy-gas
interactions in cluster cores, and a set of optically bright,
lensed
galaxies for further 8-10m spectroscopy. All of our primary
science
goals require only the detection and characterization of
high-surface-brightness
features and are thus achievable even at the
reduced
sensitivity of WFPC2. Because of their high redshift and thus
compact
angular scale our target clusters are less adversely affected by
the
smaller field of view of WFPC2 than more nearby systems.
Acknowledging
the broad community interest in this sample we waive our
data
rights for these observations. Due to a clerical error at STScI our
approved
Cycle15 SNAP program was barred from execution for 3 months and
only
6 observations have been performed to date - reinstating this SNAP
at
Cycle16 priority is of paramount importance to reach meaningful
statistics.
WFPC2
11169
Collisions
in the Kuiper belt
For
most of the 15 year history of observations of Kuiper belt objects,
it
has been speculated that impacts must have played a major role in
shaping
the physical and chemical characteristics of these objects, yet
little
direct evidence of the effects of such impacts has been seen. The
past
18 months, however, have seen an explosion of major new discoveries
giving
some of the first insights into the influence of this critical
process.
From a diversity of observations we have been led to the
hypotheses
that: {1} satellite- forming impacts must have been common in
the
Kuiper belt; {2} such impacts led to significant chemical
modification;
and {3} the outcomes of these impacts are sufficiently
predictable
that we can now find and study these impact-derived systems
by
the chemical and physical attributes of both the satellites and the
primaries.
If our picture is correct, we now have in hand for the first
time
a set of incredibly powerful tools to study the frequency and
outcome
of collisions in the outer solar system. Here we propose three
linked
projects that would answer questions critical to the multiple
prongs
of our hypothesis. In these projects we will study the chemical
effects
of collisions through spectrophotometric observations of
collisionally
formed satellites and through the search for additional
satellites
around primaries with potential impact signatures, and we
will
study the physical effects of impacts through the examination of
tidal
evolution in proposed impact systems. The intensive HST program
that
we propose here will allow us to fully test our new hypotheses and
will
provide the ability to obtain the first extensive insights into
outer
solar system impact processes.
WFPC2
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
WFPC2
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!
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
(None)
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
10
10
FGS
REacq
03
03
OBAD
with Maneuver 26
26
SIGNIFICANT
EVENTS: (None)