HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4616
PERIOD
COVERED: 5am May 21 - 5am May 22, 2008 (DOY 142/0900z-143/0900z)
OBSERVATIONS
SCHEDULED
FGS
11210
The
Architecture of Exoplanetary Systems
Are
all planetary systems coplanar? Concordance cosmogony makes that
prediction.
It is, however, a prediction of extrasolar planetary system
architecture
as yet untested by direct observation for main sequence
stars
other than the Sun. To provide such a test, we propose to carry
out
FGS astrometric studies on four stars hosting seven companions. Our
understanding
of the planet formation process will grow as we match not
only
system architecture, but formed planet mass and true distance from
the
primary with host star characteristics for a wide variety of host
stars
and exoplanet masses. We propose that a series of FGS astrometric
observations
with demonstrated 1 millisecond of arc per-observation
precision
can establish the degree of coplanarity and component true
masses
for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD
128311
{planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD
222404AB
= gamma Cephei {planet+star}. In each case the companion is
identified
as such by assuming that the minimum mass is the actual mass.
For
the last target, a known stellar binary system, the companion orbit
is
stable only if coplanar with the AB binary orbit.
NIC1/NIC2/NIC3
8795
NICMOS
Post-SAA calibration - CR Persistence Part 6
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 i
mages.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
NIC3
11120
A
Paschen-Alpha Study of Massive Stars and the ISM in the Galactic
Center
The
Galactic center (GC) is a unique site for a detailed study of a
multitude
of complex astrophysical phenomena, which may be common to
nuclear
regions of many galaxies. Observable at resolutions
unapproachable
in other galaxies, the GC provides an unparalleled
opportunity
to improve our understanding of the interrelationships of
massive
stars, young stellar clusters, warm and hot ionized gases,
molecular
clouds, large scale magnetic fields, and black holes. We
propose
the first large-scale hydrogen Paschen alpha line survey of the
GC
using NICMOS on the Hubble Space Telescope. This survey will lead to
a
high resolution and high sensitivity map of the Paschen alpha line
emission
in addition to a map of foreground extinction, made by
comparing
Paschen alpha to radio emission. This survey of the inner 75
pc
of the Galaxy will provide an unprecedented and complete search for
sites
of massive star formation. In particular, we will be able to (1)
uncover
the distribution of young massive stars in this region, (2)
locate
the surfaces of adjacent molecular clouds, (3) determine
important
physical parameters of the ionized gas, (4) identify compact
and
ultra-compact HII regions throughout the GC. When combined with
existing
Chandra and Spitzer surveys as well as a wealth of other
multi-wavelength
observations, the results will allow us to address such
questions
as where and how massive stars form, how stellar clusters are
disrupted,
how massive stars shape and heat the surrounding medium, and
how
various phases of this medium are interspersed.
NIC3
11195
Morphologies
of the Most Extreme High-Redshift Mid-IR-luminous Galaxies
II:
The `Bump' Sources
The
formative phase of some of the most massive
galaxies
may be extremely luminous, characterized by intense star- and
AGN-formation.
Till now, few such galaxies have been unambiguously
identified
at high redshift, and thus far we have been restricted to
studying
the low-redshift ultraluminous infrared galaxies as possible
analogs.
We have recently discovered a sample of objects which may
indeed
represent this early phase in galaxy formation, and are
undertaking
an extensive multiwavelength study of this population. These
objects
are optically extremely faint {R>26} but nevertheless bright at
mid-infrared
wavelengths {F[24um] > 0.5 mJy}. Mid-infrared spectroscopy
with
Spitzer/IRS reveals that they have redshifts z~2, implying
luminosities
~1E13 Lsun. Their mid-IR SEDs fall into two broad, perhaps
overlapping,
categories. Sources with brighter F[24um] exhibit power-law
SEDs
and SiO absorption features in their mid-IR spectra characteristic
of
AGN, whereas those with fainter F[24um] show a "bump" characteristic
of
the redshifted 1.6um peak from a stellar population, and PAH emission
characteristic
of starformation. We have begun obtaining HST images of
the
brighter sources in Cycle 15 to obtain identifications and determine
kpc-scale
morphologies for these galaxies. Here, we aim to target the
second
class {the "bump" sources} with the goal of determining if these
constitute
morphologically different objects, or simply a "low-AGN"
state
of the brighter class. The proposed observations will help us
determine
whether these objects are merging systems, massive obscured
starbursts
{with obscuration on kpc scales!} or very reddened {locally
obscured}
AGN hosted by intrinsically low-luminosity galaxies.
NIC3
11334
NICMOS
Cycle 16 Spectrophotometry
Observation
of the three primary WD flux standards must be repeated to
refine
the NICMOS absolute calibration and monitor for sensitivity
degradation.
So far, NICMOS grism spectrophotometry is available for
only
~16 stars with good STIS spectra at shorter wavelengths. There are
more
in the HST CALSPEC standard star data base with good STIS spectra
that
would also become precise IR standards with NICMOS absolute SED
measurements.
Monitoring the crucial three very red stars (M, L, T) for
variability
and better S/N in the IR. Apparent variability was
discovered
at shorter wavelengths during the ACS cross-calibration work
that
revealed a ~2% discrepancy of the cool star fluxes with respect to
the
hot primary WD standards. About a third of these stars are bright
enough
to do in one orbit, the rest require 2 orbits.
WFPC2
11227
The
orbital period for an ultraluminous X-ray source in NGC1313
The
ultraluminous X-ray sources {ULXs} are extragalactic point sources
with
luminosities that exceed the Eddington luminosity for conventional
stellar-mass
black holes by factors of 10 - 100. It has been hotly
debated
whether the ULXs are just common stellar-mass black hole sources
with
beamed emission or whether they are sub-Eddington sources that are
powered
by the long-sought intermediate mass black holes {IMBH}. To
firmly
decide this question, one must obtain dynamical mass measurements
through
photometric and spectroscopic monitoring of the secondaries of
these
system. The crucial first step is to establish the orbital period
of
a ULX, and arguably the best way to achieve this goal is by
monitoring
its ellipsoidal light curve. The extreme ULX NGC1313 X-2
provides
an outstanding target for an orbital period determination
because
its relatively bright optical counterpart {V = 23.5} showed a
15%
variation between two HST observations separated by three months.
This
level of variability is consistent with that expected for a tidally
distorted
secondary star. Here we propose a set of 20 imaging
observations
with HST/WFPC2 to define the orbital period. This would be
the
first photometric measurement of the orbital period of a ULX binary.
Subsequently,
we will propose to obtain spectroscopic observations to
obtain
its radial velocity amplitude and thereby a dynamical estimate of
its
mass.
WFPC2
11235
HST
NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies
in
the Local Universe
At
luminosities above 10^11.4 L_sun, the space density of far-infrared
selected
galaxies exceeds that of optically selected galaxies. These
`luminous
infrared galaxies' {LIRGs} are primarily interacting or
merging
disk galaxies undergoing enhanced star formation and Active
Galactic
Nuclei {AGN} activity, possibly triggered as the objects
transform
into massive S0 and elliptical merger remnants. We propose
NICMOS
NIC2 imaging of the nuclear regions of a complete sample of 88
L_IR
> 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised
Bright
Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}.
This
sample is ideal not only in its completeness and sample size, but
also
in the proximity and brightness of the galaxies. The superb
sensitivity
and resolution of NICMOS NIC2 on HST enables a unique
opportunity
to study the detailed structure of the nuclear regions,
where
dust obscuration may mask star clusters, AGN and additional nuclei
from
optical view, with a resolution significantly higher than possible
with
Spitzer IRAC. This survey thus provides a crucial component to our
study
of the dynamics and evolution of IR galaxies presently underway
with
Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88
galaxies.
Imaging will be done with the F160W filter {H-band} to examine
as
a function of both luminosity and merger stage {i} the luminosity and
distribution
of embedded star clusters, {ii} the presence of optically
obscured
AGN and nuclei, {iii} the correlation between the distribution
of
1.6 micron emission and the mid- IR emission as detected by Spitzer
IRAC,
{iv} the evidence of bars or bridges that may funnel fuel into the
nuclear
region, and {v} the ages of star clusters for which photometry
is
available via ACS/WFC observations. The NICMOS data, combined with
the
HST ACS, Spitzer, and GALEX observations of this sample, will result
in
the most comprehensive study of merging and interacting galaxies to
date.
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
11
11
FGS
REacq
03
03
OBAD
with Maneuver 28
28
SIGNIFICANT
EVENTS: (None)