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)