HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4519
PERIOD
COVERED: UT January 03, 2008 (DOY 003)
OBSERVATIONS
SCHEDULED
ACS/SBC
11145
Probing
the Planet Forming Region of T Tauri Stars in Chamaeleon
By
studying the inner, planet-forming regions of circumstellar disks
around
low-mass pre- main sequence stars we can refine theories of giant
planet
formation and develop timescales for the evolution of disks and
their
planets. Spitzer infrared observations of T Tauri stars in the
Chamaeleon
star-forming region have given us an unprecedented look at
dust
evolution in young objects. However, despite this ground breaking
progress
in studying the dust in young disks, the gas properties of the
inner
disk remain essentially unknown. Using ACS on HST, we propose to
measure
the H_2 emission originating in the innermost disk regions of
classical
T Tauri stars in different stages of evolution with the
objective
of revealing the timescales of gas dissipation and its
relationship
to dust evolution. This proposal is part of a comprehensive
effort
with approved programs on Spitzer, Gemini, and Magellan that aim
to
characterize the state of gas and dust in disks where planets may
already
have formed.
ACS/SBC
11158
HST
Imaging of UV emission in Quiescent Early-type Galaxies
We
have constructed a sample of early type galaxies at z~0.1 that have
blue
UV-optical colors, yet also show no signs of optical emission, or
extended
blue light. We have cross- correlated the SDSS catalog and the
Galaxy
Evolution Explorer Medium Imaging Survey to select a sample of
galaxies
where this UV emission is strongest. The origin of the UV
rising
flux in these galaxies continues to be debated, and the
possibility
that some fraction of these galaxies may be experiencing low
levels
of star formation cannot be excluded. There is also a possibility
that
low level AGN activity {as evidenced by a point source} is
responsbile
We propose to image the UV emission using the HST/SBC and to
explore
the morphology of the UV emission relative to the optical light.
WFPC2
10583
Resolving
the LMC Microlensing Puzzle: Where Are the Lensing Objects ?
We
are requesting 32 HST orbits to help ascertain the nature of the
population
that gives rise to the observed set of microlensing events
towards
the LMC. The SuperMACHO project is an ongoing ground-based
survey
on the CTIO 4m that has demonstrated the ability to detect LMC
microlensing
events in real-time via frame subtraction. The improvement
in
angular resolution and photometric accuracy available from HST will
allow
us to 1} confirm that the detected flux excursions arise from LMC
source
stars rather than extended objects {such as for background
supernovae
or AGN}, and 2} obtain reliable baseline flux measurements
for
the objects in their unlensed state. The latter measurement is
important
to resolve degeneracies between the event timescale and
baseline
flux, which will yield a tighter constraint on the microlensing
optical
depth.
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
11142
Revealing
the Physical Nature of Infrared Luminous Galaxies at 0.3
We
aim to determine physical properties of IR luminous galaxies at
0.3<z<2.7
by requesting coordinated HST/NIC2 and MIPS 70um observations
of
a unique, 24um flux- limited sample with complete Spitzer mid-IR
spectroscopy.
The 150 sources investigated in this program have S{24um}
>
0.8mJy and their mid-IR spectra have already provided the majority
targets
with spectroscopic redshifts {0.3<z<2.7}. The proposed
150~orbits
of NIC2 and 66~hours of MIPS 70um will provide the physical
measurements
of the light distribution at the rest-frame ~8000A and
better
estimates of the bolometric luminosity. Combining these
parameters
together with the rich suite of spectral diagnostics from the
mid-IR
spectra, we will {1} measure how common mergers are among LIRGs
and
ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers
of
z>1 ULIRGs, as in the local Universe. {2} study the co-evolution of
star
formation and blackhole accretion by investigating the relations
between
the fraction of starburst/AGN measured from mid-IR spectra vs.
HST
morphologies, L{bol} and z. {3} obtain the current best estimates of
the
far- IR emission, thus L{bol} for this sample, and establish if the
relative
contribution of mid-to- far IR dust emission is correlated with
morphology
{resolved vs. unresolved}.
NIC2
11166
The
Mass-dependent Evolution of the Black Hole-Bulge Relations
In
the local universe, the masses of giant black holes are correlated
with
the luminosities, masses and velocity dispersions of their host
galaxy
bulges. This indicates a surprisingly close connection between
the
evolution of galactic nuclei (on parsec scales) and of stars on kpc
scales.
A key observational test of proposed explanations for these
correlations
is to measure how they have evolved over cosmic time. Our
ACS
imaging of 20 Seyfert 1 galaxies at z=0.37 showed them to have
smaller
bulges (by a factor of 3) for a given central black hole mass
than
is found in galaxies in the present-day universe. However, since
all
our sample galaxies had black hole masses in the range 10^8.0--8.5
Msun,
we could only measure the OFFSET in black hole mass to bulge
luminosity
ratios from the present epoch. By extending this study to
black
hole masses another factor of 10 lower, we propose to determine
the
full CORRELATION of black hole mass with host galaxy properties at a
lookback
time of 4 Gyrs and to test mass-dependency of the evolution. We
have
selected 14 Seyfert galaxies from SDSS DR5 whose narrow Hbeta
emission
lines (and estimated nuclear luminosities) imply that they have
black
hole masses around 10^7 Msuns. We will soon complete our Keck
spectroscopic
measures of their bulge velocity dispersions. We need a
1-orbit
NICMOS image of each galaxy to separate its nonstellar
luminosity
from its bulge and disk. This will allow us to make the first
determination
of the full black hole/bulge relations at z=0.37 (e.g. M-L
and
M-sigma), as well as a test of whether active galaxies obey the
Fundamental
Plane relation at that epoch.
NIC2
11219
Active
Galactic Nuclei in nearby galaxies: a new view of the origin of
the
radio-loud radio- quiet dichotomy?
Using
archival HST and Chandra observations of 34 nearby early-type
galaxies
{drawn from a complete radio selected sample} we have found
evidence
that the radio-loud/radio-quiet dichotomy is directly connected
to
the structure of the inner regions of their host galaxies in the
following
sense: [1] Radio-loud AGN are associated with galaxies with
shallow
cores in their light profiles [2] Radio-quiet AGN are only
hosted
by galaxies with steep cusps. Since the brightness profile is
determined
by the galaxy's evolution, through its merger history, our
results
suggest that the same process sets the AGN flavour. This
provides
us with a novel tool to explore the co-evolution of galaxies
and
supermassive black holes, and it opens a new path to understand the
origin
of the radio-loud/radio-quiet AGN dichotomy. Currently our
analysis
is statistically incomplete as the brightness profile is not
available
for 82 of the 116 targets. Most galaxies were not observed
with
HST, while in some cases the study is obstructed by the presence of
dust
features. We here propose to perform an infrared NICMOS snapshot
survey
of these 82 galaxies. This will enable us to i} test the reality
of
the dichotomic behaviour in a substantially larger sample; ii} extend
the
comparison between radio-loud and radio-quiet AGN to a larger range
of
luminosities.
WFPC2/NIC1
11083
The
Structure, Formation and Evolution of Galactic Cores and Nuclei
A
surprising result has emerged from the ACS Virgo Cluster Survey
{ACSVCS},
a program to obtain ACS/WFC gz imaging for a large, unbiased
sample
of 100 early-type galaxies in the Virgo Cluster. On subarcsecond
scales
{i.e., <0.1"-1"}, the HST brightness profiles vary systematically
from
the brightest giants {which have nearly constant surface brightness
cores}
to the faintest dwarfs {which have compact stellar nuclei}.
Remarkably,
the fraction of galaxy mass contributed by the nuclei in the
faint
galaxies is identical to that contributed by supermassive black
holes
in the bright galaxies {0.2%}. These findings strongly suggest
that
a single mechanism is responsible for both types of Central Massive
Object:
most likely internally or externally modulated gas inflows that
feed
central black holes or lead to the formation of "nuclear star
clusters".
Understanding the history of gas accretion, star formation
and
chemical enrichment on subarcsecond scales has thus emerged as the
single
most pressing question in the study of nearby galactic nuclei,
either
active or quiescent. We propose an ambitious HST program {199
orbits}
that constitutes the next, obvious step forward:
high-resolution,
ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W}
imaging
for the complete ACSVCS sample. By capitalizing on HST's unique
ability
to provide high-resolution images with a sharp and stable PSF at
UV
and IR wavelengths, we will leverage the existing optical HST data to
obtain
the most complete picture currently possible for the history of
star
formation and chemical enrichment on these small scales. Equally
important,
this program will lead to a significant improvement in the
measured
structural parameters and density distributions for the stellar
nuclei
and the underlying galaxies, and provide a sensitive measure of
"frosting"
by young stars in the galaxy cores. By virtue of its superb
image
quality and stable PSF, NICMOS is the sole instrument capable of
the
IR observations proposed here. In the case of the WFPC2
observations,
high-resolution UV imaging {< 0.1"} is a capability unique
to
HST, yet one that could be lost at anytime.
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
11290
Dynamical
Masses and Third Bodies in the Sirius System
Sirius
B is the nearest and brightest of all white dwarfs (WDs), but it
is
fiendishly difficult to observe from the ground because of the
overwhelming
brightness of Sirius A. We propose a continuation of our
program
of imaging observations of the Sirius system with WFPC2, which
has
been underway since 2001. The resulting astrometric data will not
only
greatly improve the precision of the binary orbit and the dynamical
mass
measurements for both the main-sequence and WD components, but will
also
test definitively for the claimed presence of a third body in this
famous
system, down to planetary masses. At present, there is a
tantalizing
suggestion in our data that there indeed may exist a
substellar
or planetary third body in the system. Our team has also
obtained
superb spectra of Sirius B using STIS, and we have achieved an
excellent
fit to the spectrum using model stellar atmospheres. However,
the
implied mass of the WD disagrees significantly with the dynamical
mass
implied by the existing visual-binary orbit (which still has to be
based
on a combination of low-accuracy ground-based astrometry plus the
small
number of existing HST astrometric observations). This is another
critical
motivation for improving the astrometry.
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
13
13
FGS
REacq
01
01
OBAD
with Maneuver
28
28
SIGNIFICANT
EVENTS: (None)