Notice: For the foreseeable future, the daily reports may
contain
apparent discrepancies between some proposal descriptions
and the listed
instrument usage. This is due to the conversion of
previously approved
ACS WFC or HRC observations into WFPC2, or NICMOS
observations
subsequent to the loss of ACS CCD science capability in
late January.
HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4332
PERIOD COVERED: UT April 03, 2007 (DOY 092)
OBSERVATIONS SCHEDULED
WFPC2 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.
WFPC2 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.
FGS 10612
Binary Stars in Cyg OB2: Relics of Massive Star Formation
in a
Super-Star Cluster
We propose to make a high angular resolution SNAP survey
of the massive
stars in the nearby, super-star cluster Cyg OB2. We will
use FGS1r TRANS
mode observations to search for astrometric companions in
the separation
range of 0.01 to 1.00 arcsec and in the magnitude
difference range
smaller than 4 magnitudes. The observations will test the
idea that the
formation of very massive stars involves mergers and the
presence of
nearby companions. Discovery of companions to massive
stars in this
relatively nearby complex will provide guidance in the
interpretation of
apparently supermassive stars in distant locations. The
search for
companions will also be important for verification of
fundamental
parameters derived from spectroscopy, adjustments to main
sequence
fitting and distance estimations, determining third light
contributions
of eclipsing binaries, identifying wide colliding wind
binaries,
studying the relationship between orbital and spin angular
momentum, and
discovering binaries amenable to future mass determinations.
The massive
star environment in Cyg OB2 may be similar to the kinds
found in the
earliest epoch of star formation, so that a study of the
role of
binaries in Cyg OB2 will help us understand the formation
processes of
the first stars in the Universe.
NIC1 10859
Precise Measurements of Sgr A* Flare Activity
Correlated X-ray and near-IR flare emission from Sgr A*,
the closest
supermassive black hole, contains information about the
hydrodynamics,
energetics, and accretion behavior of matter within the
innermost ten
Schwarzschild radii of the hole. We propose HST/NICMOS
observations of
near-IR flares, in conjunction with already approved
obsrevations using
XMM-Newton {214 ksec} and CSO {3 nights}, which can make
the precise,
new measurements necessary to understand the radiation
mechanism and low
luminosity of Sgr A*. HST/NICMOS is required due to its
very low and
stable background, and its stable, tightly focused PSF,
which allow
accurate measurement of fainter flares than can be observed
using
groundbased adaptive optics systems. We will measure the
spectral index
distribution, the time-averaged flux and duration of
flares, and the
statistics of flare activity, and will confirm previously
reported
quasi-periodic variability. These measurements will have
far-reaching
implications for testing the inverse
synchrotron models of low-luminosity flares, for
understanding the
process of accretion onto and outflow from supermassive
black holes, and
for constraining the acceleration mechanism of flares and
the inferred
black hole spin. This knowledge, in turn, will help us
understand more
generally low-luminosity AGN and X-ray binaries in a very
low/quiescent
accretion state.
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA calibration - CR Persistence Part 6
A new proceedure proposed to alleviate the CR-persistence
problem of
NICMOS. Dark frames will be obtained immediately upon
exiting the SAA
contour 23, and everytime 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 i
mages. Each observation will need its own CRMAP, as
different SAA
passages leave different imprints on the NICMOS detectors.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation
Anomaly
Monitor
Intflat observations will be taken to provide a linearity
check: the
linearity test consists of a series of intflats in F555W,
in each gain
and each shutter. A combination of intflats, visflats, and
earthflats
will be used to check the repeatability of filter wheel
motions.
{Intflat sequences tied to decons, visits 1-18 in prop
10363, have been
moved to the cycle 15 decon proposal xxxx for easier
scheduling.} Note:
long-exposure WFPC2 intflats must be scheduled during ACS
anneals to
prevent stray light from the WFPC2 lamps from
contaminating long ACS
external exposures.
WFPC2 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 any any time.
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
09
09
FGS
REacq
05
05
OBAD with Maneuver
26
26
SIGNIFICANT EVENTS: (None)