DAILY REPORT #4726 - Thu 30 Oct 2008 02:18:PM
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT #4726
PERIOD COVERED: 5am October 28 - 5am October 29, 2008 (DOY
302/0900z-303/0900z)
OBSERVATIONS SCHEDULED
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.
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 11113
Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution
The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising and
unexpected results. We have found a strong concentration of binaries
among low-inclination Classicals, a possible size cutoff to binaries
among the Centaurs, an apparent preference for nearly equal mass
binaries, and a strong increase in the number of binaries at small
separations. We propose to continue this successful program in Cycle 16;
we expect to discover at least 13 new binary systems, targeted to
subgroups where these discoveries can have the greatest impact.
WFPC2 11130
AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge
Paradigm, Part II
The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9 solar
mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {<10^6 solar masses}, if they exist, may
offer important clues to the nature of the seeds of supermassive black
holes. Using the SDSS, our group has successfully uncovered a new
population of AGNs with intermediate-mass black holes that reside in
low-luminosity galaxies. However, very little is known about the
detailed morphologies or structural parameters of the host galaxies
themselves, including the crucial question of whether they have bulges
or not. Surprisingly, the majority of the targets of our Cycle 14 pilot
program have structural properties similar to dwarf elliptical galaxies.
The statistics from this initial study, however, are really too sparse
to reach definitive conclusions on this important new class of black
holes. We wish to extend this study to a larger sample, by using the
Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175
AGNs with intermediate- mass black holes selected from our final SDSS
search. We are particularly keen to determine whether the hosts contain
bulges, and if so, how the fundamental plane properties of the host
depend on the mass of their central black holes. We will also
investigate the environment of this unique class of AGNs.
WFPC2 11289
SL2S: The Strong Lensing Legacy Survey
Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS,
GOODS, etc.} are producing spectacular results for galaxy masses roughly
below a transition mass M~10^13 Mo. The observed lens properties and
their evolution up to z~0.2, consistent with numerical simulations, can
be described by isothermal elliptical potentials. In contrast, modeling
of giant arcs in X-ray luminous clusters {halo masses M >~10^13 Mo}
favors NFW mass profiles, suggesting that dark matter halos are not
significantly affected by baryon cooling. Until recently, lensing
surveys were neither deep nor extended enough to probe the intermediate
mass density regime, which is fundamental for understanding the assembly
of structures. The CFHT Legacy Survey now covers 125 square degrees, and
thus offers a large reservoir of strong lenses probing a large range of
mass densities up to z~1. We have extracted a list of 150 strong lenses
using the most recent CFHTLS data release via automated procedures.
Following our first SNAPSHOT proposal in cycle 15, we propose to
continue the Hubble follow-up targeting a larger list of 130 lensing
candidates. These are intermediate mass range candidates {between
galaxies and clusters} that are selected in the redshift range of 0.2-1
with no a priori X-ray selection. The HST resolution is necessary for
confirming the lensing candidates, accurate modeling of the lenses, and
probing the total mass concentration in galaxy groups up to z~1 with the
largest unbiased sample available to date.
WFPC2 11902
Arp 273: Different Responses in Interacting Galaxies
We propose HST WFPC2 observations of the interacting spiral galaxies Arp
273. This is a fascinating object in its own right, in that the two
interacting galaxies exhibit different behaviors due to the interaction.
The disk of the larger galaxy is extremely disturbed, but its nucleus
shows few signs of activity (it is a LINER). In the smaller (nearly
edge-on) galaxy on the other hand, the disk appears to be almost intact,
but its nucleus experiences a starburst. The proposed observations are
also intended to demonstrate that WFPC2 can produce outstanding science
(and images) after the transition to Side B.
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 FAILURE TIMES
FGS GSacq 10 10
FGS REacq 03 03
OBAD with Maneuver 26 25 302/0203z
SIGNIFICANT EVENTS:
Flash Report: NICMOS Recovery to SAA Operate
As of 302/11:59:47 UTC, NICMOS successfully completed its stored command
recovery to SAA Operate mode via the SA301 SMS.
DAILY REPORT #4726
PERIOD COVERED: 5am October 28 - 5am October 29, 2008 (DOY
302/0900z-303/0900z)
OBSERVATIONS SCHEDULED
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.
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 11113
Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution
The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising and
unexpected results. We have found a strong concentration of binaries
among low-inclination Classicals, a possible size cutoff to binaries
among the Centaurs, an apparent preference for nearly equal mass
binaries, and a strong increase in the number of binaries at small
separations. We propose to continue this successful program in Cycle 16;
we expect to discover at least 13 new binary systems, targeted to
subgroups where these discoveries can have the greatest impact.
WFPC2 11130
AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge
Paradigm, Part II
The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9 solar
mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {<10^6 solar masses}, if they exist, may
offer important clues to the nature of the seeds of supermassive black
holes. Using the SDSS, our group has successfully uncovered a new
population of AGNs with intermediate-mass black holes that reside in
low-luminosity galaxies. However, very little is known about the
detailed morphologies or structural parameters of the host galaxies
themselves, including the crucial question of whether they have bulges
or not. Surprisingly, the majority of the targets of our Cycle 14 pilot
program have structural properties similar to dwarf elliptical galaxies.
The statistics from this initial study, however, are really too sparse
to reach definitive conclusions on this important new class of black
holes. We wish to extend this study to a larger sample, by using the
Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175
AGNs with intermediate- mass black holes selected from our final SDSS
search. We are particularly keen to determine whether the hosts contain
bulges, and if so, how the fundamental plane properties of the host
depend on the mass of their central black holes. We will also
investigate the environment of this unique class of AGNs.
WFPC2 11289
SL2S: The Strong Lensing Legacy Survey
Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS,
GOODS, etc.} are producing spectacular results for galaxy masses roughly
below a transition mass M~10^13 Mo. The observed lens properties and
their evolution up to z~0.2, consistent with numerical simulations, can
be described by isothermal elliptical potentials. In contrast, modeling
of giant arcs in X-ray luminous clusters {halo masses M >~10^13 Mo}
favors NFW mass profiles, suggesting that dark matter halos are not
significantly affected by baryon cooling. Until recently, lensing
surveys were neither deep nor extended enough to probe the intermediate
mass density regime, which is fundamental for understanding the assembly
of structures. The CFHT Legacy Survey now covers 125 square degrees, and
thus offers a large reservoir of strong lenses probing a large range of
mass densities up to z~1. We have extracted a list of 150 strong lenses
using the most recent CFHTLS data release via automated procedures.
Following our first SNAPSHOT proposal in cycle 15, we propose to
continue the Hubble follow-up targeting a larger list of 130 lensing
candidates. These are intermediate mass range candidates {between
galaxies and clusters} that are selected in the redshift range of 0.2-1
with no a priori X-ray selection. The HST resolution is necessary for
confirming the lensing candidates, accurate modeling of the lenses, and
probing the total mass concentration in galaxy groups up to z~1 with the
largest unbiased sample available to date.
WFPC2 11902
Arp 273: Different Responses in Interacting Galaxies
We propose HST WFPC2 observations of the interacting spiral galaxies Arp
273. This is a fascinating object in its own right, in that the two
interacting galaxies exhibit different behaviors due to the interaction.
The disk of the larger galaxy is extremely disturbed, but its nucleus
shows few signs of activity (it is a LINER). In the smaller (nearly
edge-on) galaxy on the other hand, the disk appears to be almost intact,
but its nucleus experiences a starburst. The proposed observations are
also intended to demonstrate that WFPC2 can produce outstanding science
(and images) after the transition to Side B.
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 FAILURE TIMES
FGS GSacq 10 10
FGS REacq 03 03
OBAD with Maneuver 26 25 302/0203z
SIGNIFICANT EVENTS:
Flash Report: NICMOS Recovery to SAA Operate
As of 302/11:59:47 UTC, NICMOS successfully completed its stored command
recovery to SAA Operate mode via the SA301 SMS.