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 # 4420
PERIOD
COVERED: UT August 06, 2007 (DOY 218)
OBSERVATIONS
SCHEDULED
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.
NIC1
10889
The
Nature of the Halos and Thick Disks of Spiral Galaxies
We
propose to resolve the extra-planar stellar populations of the thick
disks
and halos of seven nearby, massive, edge-on galaxies using ACS,
NICMOS,
and WFPC2 in parallel. These observations will provide accurate
star
counts and color-magnitude diagrams 1.5 magnitudes below the tip of
the
Red Giant Branch sampled along the two principal axes and one
intermediate
axis of each galaxy. We will measure the metallicity
distribution
functions and stellar density profiles from star counts
down
to very low average surface brightnesses, equivalent to ~32 V-mag
per
square arcsec. These observations will provide the definitive HST
study
of extra-planar stellar populations of spiral galaxies. Our
targets
cover a range in galaxy mass, luminosity, and morphology and as
function
of these galaxy properties we will provide: - The first
systematic
study of the radial and isophotal shapes of the diffuse
stellar
halos of spiral galaxies - The most detailed comparative study
to
date of thick disk morphologies and stellar populations - A
comprehensive
analysis of halo and thick disk metallicity distributions
as
a function of galaxy type and position within the galaxy. - A
sensitive
search for tidal streams - The first opportunity to directly
relate
globular cluster systems to their field stellar population We
will
use these fossil records of the galaxy assembly process preserved
in
the old stellar populations to test halo and thick disk formation
models
within the hierarchical galaxy formation scheme. We will test
LambdaCDM
predictions on sub-galactic scales, where it is difficult to
test
using CMB and galaxy redshift surveys, and where it faces its most
serious
difficulties.
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
10802
SHOES-Supernovae,
HO, for the Equation of State of Dark energy
The
present uncertainty in the value of the Hubble constant {resulting
in
an uncertainty in Omega_M} and the paucity of
redshifts
exceeding 1 are now the leading obstacles to determining the
nature
of dark energy. We propose a single, integrated set of
observations
for Cycle 15 that will provide a 40% improvement in
constraints
on dark energy. This program will observe known Cepheids in
six
reliable hosts of
uncertainty
in H_0 by a factor of two because of the smaller dispersion
along
the instability strip, the diminished extinction, and the weaker
metallicity
dependence in the infrared. In parallel with ACS, at the
same
time the NICMOS observations are underway, we will discover and
follow
a sample of
measurements,
along with prior constraints from WMAP, will provide a
great
improvement in HST's ability to distinguish between a static,
cosmological
constant and dynamical dark energy. The Hubble Space
Telescope
is the only instrument in the world that can make these IR
measurements
of Cepheids beyond the Local Group, and it is the only
telescope
in the world that can be used to find and follow supernovae at
z
> 1. Our program exploits both of these unique capabilities of HST to
learn
more about one of the greatest mysteries in science.
NIC3
11080
Exploring
the Scaling Laws of Star Formation
As
a variety of surveys of the local and distant Universe are
approaching
a full census of galaxy populations, our attention needs to
turn
towards understanding and quantifying the physical mechanisms that
trigger
and regulate the large-scale star formation rates {SFRs} in
galaxies.
WFPC2
10818
Very
Young Globular Clusters in M31 ?
We
propose to use HST's unique high spatial resolution imaging
capabilities
to conclusively confirm or refute the presence of alleged
very
young globular clusters in M31. Such young globular clusters with
ages
< 3 Gyr are not present in our galaxy, and, if real, would lead to
a
striking difference in the age distribution of the GCs between M31 and
the
in
M31 is confirmed through our proposed ACS imaging {now WFPC2 imaging}
with
HST, this would suggest major differences in the history of
assembly
of the two galaxies, with probable substantial late accretion
into
M31 which did not occur in our own galaxy.
WFPC2
11023
WFPC2
CYCLE 15 Standard Darks - part 1
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
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
11178
Probing
Solar System History with Orbits, Masses, and Colors of
Transneptunian
Binaries
The
recent discovery of numerous transneptunian binaries {TNBs} opens a
window
into dynamical conditions in the protoplanetary disk where they
formed
as well as the history of subsequent events which sculpted the
outer
Solar System and emplaced them onto their present day heliocentric
orbits.
To date, at least 47 TNBs have been discovered, but only about a
dozen
have had their mutual orbits and separate colors determined,
frustrating
their use to investigate numerous important scientific
questions.
The current shortage of data especially cripples scientific
investigations
requiring statistical comparisons among the ensemble
characteristics.
We propose to obtain sufficient astrometry and
photometry
of 23 TNBs to compute their mutual orbits and system masses
and
to determine separate primary and secondary colors, roughly tripling
the
sample for which this information is known, as well as extending it
to
include systems of two near-equal size bodies. To make the most
efficient
possible use of HST, we will use a
optimally
schedule our observations.
WFPC2
11203
A
Search for Circumstellar Disks and Planetary-Mass Companions around
Brown
Dwarfs in Taurus
During
a 1-orbit program in Cycle 14, we used WFPC2 to obtain the first
direct
image of a circumstellar disk around a brown dwarf. These data
have
provided fundamental new constraints on the formation process of
brown
dwarfs and the properties of their disks. To search for additional
direct
detections of disks around brown dwarfs and to search for
planetary-mass
companions to these objects, we propose a WFPC2 survey of
32
brown dwarfs in the Taurus star-forming region.
WFPC2
11307
Completing
the ACS Nearby Galaxy Survey with WFPC2
We
are requesting 25 orbits of Director's Discretionary Time to complete
the
primary science goals of our highly-ranked ACS Nearby Galaxy Survey
Treasury
program {ANGST}. Our program lost ~2/3 of its orbits due to the
ACS
failure. Roughly half of these were restored as a result of an
appeal
to the Telescope Time Review Board which re-scoped the program.
The
Board's response to our appeal was explicit in terms of which
targets
were to be observed and how. We were directed to request
Director's
discretionary time for the components of the appeal which
were
not granted by the Review Board, but which were vital to the
success
of the program. The observing strategy for ANGST is two-fold: to
obtain
one deep field per galaxy which enables derivation of an accurate
ancient
star formation history, and to obtain radial tilings sufficient
for
recovering the full star formation history. The Review Board granted
WFPC2
observations for deep fields in 7 galaxies, but no time for radial
tilings.
However, recovering the full star formation history of a galaxy
is
not possible without additional radial coverage. We have searched the
archives
for observations which may be used in place of the tilings
{conceding
some of the Treasury goals, but providing significant
constraints
on the full star formation history}, and have identified
suitable
observations for all but two of the galaxies. Here we request
DD
time for radial tilings for those last two galaxies.
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
06
06
FGS
REacq
09
09
OBAD
with Maneuver
28
28
SIGNIFICANT
EVENTS: (None)