Daily Report #4518

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT***** # 4518

PERIOD COVERED: UT January 02, 2008 (DOY 002)

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 11309

Chemical Composition of an Exo-Neptune

The recent discovery that the Neptune-like exoplanet GJ 436 b
transits
its host star has presented us the first chance to observationally
study ice giant formation beyond our solar system {Gillon et al.
2007}. Using Directors Discretionary time, we propose to obtain a
high-precision light curve of the GJ 436 b transit with the FGS in
order to improve the current radius determination for this planet.
Measuring a precise radius for GJ 436 b will allow us to ascertain
whether the planet has a pure water vapor or H/He envelope like Uranus
and Neptune. Knowing this will constrain its formation and evolution
and help place our own solar system ice giants in a broader context.
Additionally, a precise radius for GJ 436 b will be a necessity for
interpreting the certain follow-up observations of this unique
system.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic
O Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long
term spectroscopic and high angular resolution observations to
determine their masses and distances. The results will also be
important for the interpretation of the spectra of suspected and newly
identified binary and multiple systems.

FGS 11213

Distances to Eclipsing M Dwarf Binaries

We propose HST FGS observations to measure accurate distances of 5
nearby M dwarf eclipsing binary systems, from which model-independent
luminosities can be calculated. These objects have either poor or no
existing parallax measurements. FGS parallax determinations for these
systems, with their existing dynamic masses determined to better than
0.5%, would serve as model-independent anchor points for the low-mass
end of the mass-luminosity diagram.

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 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- and M-sigma), as well as a test of whether active
galaxies obey the Fundamental Plane relation at that epoch.

NIC3 11080

Exploring the Scaling Laws of Star Formation

As a variety of surveys of the local and distant Universe are
approaching a full census of galaxy populations, our attention needs
to turn towards understanding and quantifying the physical mechanisms
that trigger and regulate the large-scale star formation rates {SFRs}
in 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.

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 **** 28**************** 28

SIGNIFICANT EVENTS: (None)