HUBBLE SPACE TELESCOPE - Continuing to collect World
Class Science
DAILY REPORT # 4611
PERIOD COVERED: 5am May 14 - 5am May 15, 2008 (DOY
135/0900z-136/0900z)
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 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/WFPC2 11142
Revealing the Physical Nature of Infrared Luminous
Galaxies at 0.3<z<2.7
Using HST and Spitzer
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}.
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.
S/C 11163
Accreting Pulsating White Dwarfs in Cataclysmic
Variables
Recent ground-based observations have increased the
number of known
pulsating white dwarfs in close binaries with active mass
transfer
{cataclysmic variables} from 5 to 11 systems. Our past Cycles 8 and
11
STIS observations of the first 2 known, followed by our Cycle 13
SBC
observations of the next 3 discovered, revealed the clear presence
of
the white dwarf and increased amplitude of the pulsations in the
UV
compared to the optical. The temperatures derived from the UV
spectra
show 4 systems are much hotter than non-interacting pulsating
white
dwarfs. A larger sample is needed to sort out the nature of
the
instability strip in accreting pulsators i.e. whether effects
of
composition and rotation due to accretion result in a well-
defined
instability strip as a function of Teff.
WFPC2 10888
Complexity in the Smallest Galaxies: Star Formation
History of the
Sculptor Dwarf Spheroidal
The Sculptor dwarf spheroidal galaxy {Scl dSph} is one
of the most
luminous of the Milky Way dSph satellites, suffers virtually
no
foreground confusion or reddening because of its high galactic
latitude,
and is nearby at 80 kpc from the Sun. It is of great interest
to
astronomy to understand the detailed histories of dSph galaxies
because
they may be survivors of the hierarchical merging process that
created
giant galaxies like our own. Despite this, the age distribution of
stars
in Scl dSph remains remarkably poorly constrained because of a dearth
of
high-quality color-magnitude diagrams {CMDs} of its central regions.
Scl
dSph is known to be complex on the basis of shallower photometry,
radial
velocity studies, and investigations of the metallicity; however,
the
age range of significant star-formation and the proportion of
stars
older and younger than 10 Gyr is still completely unknown. The age
of
the centrally concentrated, metal-rich population has never
been
measured. We propose to obtain deep optical images of the core of
Scl
dSph with WFPC2 in order to measure the temporal evolution of its
star-
formation rate over its entire lifetime. The ONLY way to
reliably
measure the variation in star- formation rate on Gyr timescales at
ages
of 10-13 Gyr is with photometry of a large number of stars at and
below
the oldest main-sequence turnoffs to magnitudes of {B,I} = {25.1,
24.5}.
Because of the high stellar density and resulting image crowding, it
is
impossible to achieve the required level of photometric precision
except
with diffraction-limited imaging. These data will permit the
first
reliable measurement of the star-formation history of the main body
of
Scl dSph; limited inferences from WFPC2 data in an outer field have
been
made, but they were hindered not only by small number statistics but
by
the subsequent revelation of extremely strong population gradients
in
Scl dSph, such that the stars in the existing WFPC2 field are
not
representative of the galaxy as a whole. Our proposed program will
shed
strong new light on the formation processes of the smallest
galaxies.
Only by measuring the detailed early histories of galaxies like Scl
dSph
can we evaluate the impact of outside influences like
ram-pressure
stripping, tidal stirring, and photoionization feedback on the
evolution
of small galaxies.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11307 - OBAD Failed Identification, REAcq
(1,2,1) not attempted
At
(135/20:02:03) received one (1) 486 STB ESB 1808 "TxG FHST Sanity
Check
Failed", followed at 20:03:21 by a 1902 "OBAD Failed ID". OBAD #2
attempted
10 pairs and 12 triplets. Vehicle was in RGA control, T2G mode
with
OBAD flag mnemonics showing GOBSTAT=255 (Attitude Determination
Error)
and GCHACL09=1 or (Failed State). OBAD #2 scheduled at 20:00:34
showed
errors of: V1 110479.51, V2 52540.44, V3 120870.78 and RSS
171975.02
arc-seconds. The RE-Acquisition at 20:05:28 was not attempted
as
the OBAD success flag indicated a Failed State. Ops Request
17543-2
was
successfully executed and copies of the dump for tables 369 &
370
are
attached. Additionally, ROP DF-18A was executed to dump the 486
ESB’s.
COMPLETED OPS REQUEST:
17543-2 - Dump OBAD tables
after failed OBAD @135/2021z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSacq
09
09
FGS REacq
05 04
OBAD with Maneuver
28
27
SIGNIFICANT EVENTS: (None)