HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4785

PERIOD COVERED: 5am February 4 - 5am February 5, 2009 (DOY

                           035/1000z-036/1000z)

OBSERVATIONS SCHEDULED

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 11942

Increasing the Accuracy of HST Astrometry with FGS1R

We propose to observe six exoplanetary system host stars and two

planetary nebulae central stars with FGS1r. All objects have been

previously observed under proposals GO-09233, -09969, -10989, and

-11210. These observations will significantly extend the time baseline,

permitting improvements in the determination of proper motion. This

systematic motion must be removed to get at the perturbation of

interest, either due to exoplanetary companions or the orbital motion of

the Earth (parallax). In most cases the perturbation orbits will also

improve. We improve either companion mass or PN parallax. For one

target, GJ 876, theoretical dynamical modelers have proposed an

inclination closer to 50 degrees, while FGS3 measurements indicated an

inclination closer to 84 degrees. These new data, once combined with our

older FGS3 data, will permit an independent remeasurement of the

inclination of the outermost companion, and a re-evaluation of widely

used dynamical algorithms.

NIC3 11236

Did Rare, Large Escape-Fraction Galaxies Reionize the Universe?

Lyman continuum photons produced in massive starbursts may have played a

dominant role in the reionization of the Universe. Starbursts are

important contributors to the ionizing metagalactic background at lower

redshifts as well. However, their contribution to the background depends

upon the fraction of ionizing radiation that escapes from the intrinsic

opacity of galaxies below the Lyman limit. Current surveys suggest that

the escape fraction is close to zero in most galaxies, even among young

starbursts, but is large in 15-25% of them. Non-uniform escape fractions

are expected as a result of violent events creating clear paths in small

parts of galaxies. The number of galaxies observed with high escape

fraction will result from the combination of the intrinsic number with

clear lines of sight and their orientation with respect to the observer.

We propose to measure the fraction of escaping Lyman continuum radiation

in a large sample (47) of z~0.7 starbursts in the COSMOS field. These

compact UV-luminous galaxies are good analogs to high redshift LBGs.

Using the SBC/PR130L we can quickly (1-4 orbits) detect relative escape

fractions (f_LC/f_1500) of 25% or more. This will be the first

measurement of the escape fraction in sources between z=1 and the local

universe. We expect ~10 detections. Stacking will set limits of <4% on

the relative escape fraction in the rest. We will correlate the LC

detections with the properties of the galaxies. By targeting z~0.7 in

COSMOS, we will have tremendous ancillary information on those sources.

A non-detection in all sources would be significant (99% confidence).

This would imply that QSOs provide the overwhelming majority of ionizing

radiation at z<1, requiring substantial evolution in the processes

within Lyman break galaxies which allow large escape fractions at high

redshift.

WFPC2 11130

AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge

Paradigm, Part II

The recent progress in the study of central black holes in galactic

nuclei has led to a general consensus that supermassive {10^6-10^9 solar

mass} black holes are closely connected with the formation and

evolutionary history of large galaxies, especially their bulge

component. Two outstanding issues, however, remain unresolved. Can

central black holes form in the absence of a bulge? And does the mass

function of central black holes extend below 10^6 solar masses?

Intermediate-mass black holes {<10^6 solar masses}, if they exist, may

offer important clues to the nature of the seeds of supermassive black

holes. Using the SDSS, our group has successfully uncovered a new

population of AGNs with intermediate-mass black holes that reside in

low-luminosity galaxies. However, very little is known about the

detailed morphologies or structural parameters of the host galaxies

themselves, including the crucial question of whether they have bulges

or not. Surprisingly, the majority of the targets of our Cycle 14 pilot

program have structural properties similar to dwarf elliptical galaxies.

The statistics from this initial study, however, are really too sparse

to reach definitive conclusions on this important new class of black

holes. We wish to extend this study to a larger sample, by using the

Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175

AGNs with intermediate-mass black holes selected from our final SDSS

search. We are particularly keen to determine whether the hosts contain

bulges, and if so, how the fundamental plane properties of the host

depend on the mass of their central black holes. We will also

investigate the environment of this unique class of AGNs.

WFPC2 11944

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries

among some of the most massive, least massive, and oldest stars in our

part of the Galaxy. FGS allows us to spatially resolve binary systems

that are too faint to observe using ground-based, speckle or optical

long baseline interferometry, and too close to resolve with AO. We

propose a SNAP-style program of single orbit FGS TRANS mode observations

of very massive stars in the cluster NGC 3603, luminous blue variables,

nearby low mass main sequence stars, cool subdwarf stars, and white

dwarfs. These observations will help us to (1) identify systems suitable

for follow up studies for mass determination, (2) study the role of

binaries in stellar birth and in advanced evolutionary states, (3)

explore the fundamental properties of stars near the main sequence-brown

dwarf boundary, (4) understand the role of binaries for X-ray bright

systems, (5) find binaries among ancient and nearby subdwarf stars, and

(6) help calibrate the white dwarf mass - radius relation.

WFPC2 11971

A Rare Mutual Event between Satellites of the Dwarf Planet Haumea

The dwarf planet Haumea has a fascinating history, including the

formation of two large satellites by an ancient mantle-shattering

collision. Haumea also has an exciting future with many observable

mutual events between Haumea and the smaller inner moon Namaka predicted

for the next several years. The Haumea-Namaka mutual events will provide

a wealth of information that is otherwise unattainable: the size, shape,

and spin pole of Haumea; the size, albedo, and density of Namaka; and

precise orbital constraints. The orbital orientation is not as favorable

for the outer, larger satellite Hi'iaka, but the last two possible

mutual events between Hi'iaka and Namaka occur in 2009 and will not

occur again for decades. We propose a short {5-orbit} WFPC2 resolved

photometry program to observe the first of these events, which will

occur with an estimated ~75% probability. Even catching a partial event

will measure the density of Hi'iaka to within ~15% and provide unique

insight in the formation and evolution of this exciting system.;

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               04                  04                    

FGS REacq               10                  10                    

OBAD with Maneuver 28                  28               

SIGNIFICANT EVENTS: (None)