HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4257
PERIOD COVERED: UT December 11, 2006 (DOY 345)
OBSERVATIONS SCHEDULED
ACS/HRC 10878
An ACS Prism Snapshot Survey for z~2 Lyman Limit Systems
We propose to conduct a spectroscopic survey of Lyman limit absorbers
at
redshifts 1.7 < z < 2.2, using ACS/HRC and the PR200L prism. We
have
selected 100 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 16.3 <log N_HI < 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 16.3 < log
N_HI
< 17.5 cm^-2. Third, we will identify new sightlines for measurements
of
the primordial D/H ratio. With this survey, we will also constrain
two
key quantities of cosmological relevance: First, the measurements of
dN/dz for optically thick LLS and f{N} for the PLLS are critical to
estimating the attenuation of extragalactic ionizing sources {e.g.
QSOs}. Currently, uncertainties in dN/dz and f{N} are the greatest
sources of uncertainty for inferring the shape and intensity of the
UV
background radiation field. Second, we will estimate the amount of
metals in the LLS using the f{N} and ground based observations of
metal
line transitions. It is possible that a significant fraction of the
"missing metals" at z~2 are associated with these highly
ionized
absorbers. Third, analysis of the LLS lends to investigations of the
interface between galaxies {i.e. the damped Lyman alpha systems} and
the
intergalactic medium {i.e. the Lyman alpha forest}. This survey is
ideal
for a snapshot observing program, because the on-object integration
times are less than 10 minutes, and the targets cover the majority
of
the northern sky.
ACS/HRC 11041
ACS CCDs daily monitor
This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in
ACS CCD detectors. The files, biases and dark will be used to create
reference files for science calibration. This programme will be for
the
entire lifetime of ACS. For cycle 15 the program will cover 18
months
12.1.06->05.31.08 and it has been divied into three different
proposal
each covering six months. The three proposals are
11041-11042-11043.
ACS/HRC/WFPC2/NIC3 10842
A Cepheid Distance to the Coma Cluster
We propose to use the Advanced Camera for Surveys to search for
Cepheid
variables in two spiral galaxies in the core of the Coma cluster. A
direct application of the canonical primary distance indicator at
100
Mpc will measure the far-field Hubble constant free of many of the
systematic uncertainties which beset current determinations relying
on
secondary indicators. Establishing the far-field H_o with Cepheids
will
provide one of the strongest links in the extragalactic distance
scale
and will directly calibrate the fiducial fundamental plane of
elliptical
galaxies in Coma. With ACS/HRC, S/N=5 to 10 or better can be reached
for
Cepheids with periods of 40d to 70d at mean light in 5 orbits with
the
F606W filter if H_o=72 km/s/Mpc. Efficient detection and phasing can
be
done with twelve epochs optimally spaced for periods of 40-70d.
ACS/WFC 10633
GRB afterglows and host galaxies at very high redshifts
Cosmology is beginning to constrain the nature of the earliest stars
and
galaxies to form in the universe, but direct observation of galaxies
at
z>6 remains highly challenging due to their scarcity,
intrinsically
small size, and high luminosity distance. GRB afterglows, thanks to
their extreme luminosities, offer the possibility of circumventing
these
normal constraints by providing redshifts and spectral information
which
couldn't be obtained by direct observation of the hosts themselves.
In
addition, the association of GRBs with massive stars means that they
are
a tracer of star formation, and that their hosts are likely
responsible
for a large proportion of the ionizing radiation during that era.
Our
collaboration is mounting a campaign to rapidly identify and study
candidate very high redshift bursts, bringing to bear a network of 2,
4
and 8m telescopes with nIR instrumentation. The capabilities of Swift
to
detect faint, distant GRBs, and to report accurate positions for
many
bursts in near real-time makes our program now feasible. HST is
crucial
to this endeavour, allowing us {a} to monitor the late time
afterglows
and hence compare them to lower-z bursts and test the use of GRBs as
standard candles; and {b} characterise the basic properties,
luminosities, and in some cases morphologies, of the hosts, which is
essential to understanding these primordial galaxies and their
relationship to other populations.
ACS/WFC 10880
The host galaxies of QSO2s: AGN feeding and evolution at high
luminosities
Now that the presence of supermassive black holes in the nuclei of
galaxies is a well established fact, other questions related to the
AGN
phenomena still have to be answered. Problems of particular interest
are
how the AGN gets fed, how the black hole evolves and how the
evolution
of the black hole is related to the evolution of the galaxy bulge.
Here
we propose to address some of these issues using ACS/WFC + F775W
snapshot images of 73 QSO2s with redshifts in the range 0.3<z<0.4.
These
observations will be combined with similar archival data of QSO1s
and
ground based data of Seyfert and normal galaxies. First, we will
intestigate whether interactions are the most important feeding
mechanism in high luminosity AGNs. This will be done in a
quantitative
way, comparing the asymmetry indices of QSO2 hosts with those of
lower
luminosity AGNs and normal galaxies. Second, we will do a detailed
study
of the morphology of the host galaxies of both QSO types, to
determine
if they are similar, or if there is an evolutionary trend from QSO2s
to
QSO1s. The results from this project will represent an important step
in
the understanding of AGN evolution, and may also introduce a
substantial
modification to the Unified Model.
ACS/WFC 10917
Afterglows and Environments of Short-Hard Gamma-Ray Bursts
Discovery of the first afterglows of short-hard bursts {SHBs} has led
to
a revolution in our understanding of these events, strongly
suggesting
that they originate in the mergers of compact-object binaries.
Capitalizing on this progress, we propose to pursue the next
generation
of SHB observations with HST, tracking the decay of all accessible
SHB
afterglows to late times and pinpointing the location of several
more
within the context of their host galaxies. These observations will
allow
quantitative analysis of progenitor lifetimes and short burst
environments, enable direct confrontation with population synthesis
models, and provide updated event rate estimates for the LIGO and
VIRGO
gravitational-wave detectors that are now coming on-line.
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 DARKSs. 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, ACS/WFC 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 Type Ia supernovae
at
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 Type Ia supernovae with NICMOS, reducing the
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 Type Ia supernovae at z > 1. Together, these
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.
WFPC2 10744
WFPC2 Cycle 14 Decontaminations and Associated Observations
This proposal is for the WFPC2 decontamination. Also included are
instrument monitors tied to decontamination: photometric stability
check, focus monitor, pre- and post-decontamination internals {bias,
intflats, kspots, & darks}, UV throughput check, VISFLAT sweep,
and
internal UV flat check.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary
reports
of potential non-nominal performance that will be investigated.)
HSTARS:
10555 - GSAcq(2,1,1) failed to RGA Hold (Gyro Control)
Upon acquisition of signal at 346/05:21:49, the GSAcq(2,1,1)
scheduled
at
346/05:03:05 - 04:11:10 was observed to have failed to RGA Hold due
to
search radius limit exceeded on FGS-1. One 486 ESB "a05" (FGS
Coarse
Track failed - Search Radius Limit Exceeded) was received.
Pre-acquisition OBADs (RSS) attitude error corrections values not
available pending future ETR Dump due to LOS.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSacq
05
04
FGS
REacq
10
10
OBAD with Maneuver
30
30
SIGNIFICANT EVENTS: (None)
-Lynn
Lynn F. Bassford
CHAMP HST Missions Operations Manager Lockheed Martin Mission
Services (LMMS)
GSFC PH#: 301-286-2876
"The Hubble Space Telescope is the astronomical observatory and
key to unlocking the most cosmic mysteries of the past, present and
future." - 7/26/6
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