HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4796

PERIOD COVERED: 5am February 20 - 5am February 23, 2009 (DOY

                           051/1000z-054/1000z)

OBSERVATIONS SCHEDULED

WFPC2 11991

Constraining the Late Time Lightcurve and Energy of GRB 090102

We propose to conduct a series of late time observations of the

lightcurve of the bright gamma-ray burst GRB 090102. Declared a burst of

interest by the Swift team, and with excellent broadband data covering

the prompt emission (Swift and Fermi) and afterglow (Swift, TAROT, NOT,

WHT, and several more), GRB 090102 offers a rare opportunity to probe

the physics and energetics of GRBs. Its high energy budget (>2e53 ergs

for isotropic emission) stretches plausible progenitor models, and as

yet the signatures of jet-like emission have not been observed. Our late

time observations will search for steepening of the afterglow due to

lateral expansion of the jet. This will enable us, in tandem with the

data already secured, to determine its total energy budget, and compare

this to expectations for different progenitors models. HST is vital to

this endeavour since it can reach depths essentially unattainable to

ground based technology, while its invariant PSF will allow us to

accurately remove underlying host contamination. Ultimately, the range

and quality of data secured for this burst will enable us to accurately

reconstruct the parameters of the explosion, and shed greater light on

the physical processes which under lie the production of GRBs.

WFPC2 11986

Completing HST's Local Volume Legacy

Nearby galaxies offer one of the few laboratories within which stellar

populations can be tied to multi-wavelength observations. They are thus

essential for calibrating and interpreting key astrophysical

observables, such as broad-band luminosities, durations and energy input

from starbursts, and timescales of UV, H-alpha, and FIR emission. The

study of stellar populations in nearby galaxies requires high-resolution

observations with HST, but HST's legacy for this limited set of galaxies

remains incomplete.

As a first attempt to establish this legacy, The ACS Nearby Galaxy

Survey Treasury (ANGST) began observations in late 2006. ANGST was

designed to carry out a uniform multi-color survey of a volume-limited

sample of ~70 nearby galaxies that could be used for systematic studies

of resolved stellar populations. The resulting data provide nuanced

constraints on the processes which govern star formation and galaxy

evolution, for a well-defined population of galaxies. All photometry for

the survey has been publicly released.

However, the failure of ACS 4.5 months after ANGST began taking data led

to a drastic reduction in the planned survey. The loss is two-fold.

First, the goals of completeness and uniformity were greatly

compromised, impacting global comparison studies. Second, the variety of

observed star formation histories was reduced. Given that we have never

found two galaxies with identical star formation histories, and fully

sampling the population allows us to catch those few systems whose star

formation rates and metallicities place the strongest constraints on key

astrophysical processes.

Here we propose WFPC2 observations of all remaining galaxies within the

Local Volume (D<3.5Mpc) for which current HST observations are

insufficient for meaningful stellar population studies. We will use

these observations for research on the star formation histories of

individual galaxies and the Local Volume, detailed calibrations of star

formation rate indicators, and the durations of starbursts. We will also

make them publicly available through the ANGST archive to support future

research. The proposed observations will finally complete a lasting

legacy of HST

WFPC2 11978

Luminous and Dark Matter in Disk Galaxies from Strong Lensing and

Stellar Kinematics

The formation of realistic disk galaxies within the LCDM paradigm is

still an unsolved problem. Theory is only now beginning to make

predictions for how dark matter halos respond to galaxy formation and

for the properties of disk galaxies. Measuring the density profiles of

dark matter halos on galaxy scales is therefore a strong test for the

standard paradigm of galaxy formation, offering great potential for

discovery. However, from an observational point of view, the degeneracy

between the stellar and dark matter contributions to galaxy rotation

curves remains a major road block. Strong gravitational lensing, when

coupled to spatially-resolved kinematics and stellar population models,

can solve this long-standing problem. Unfortunately, this joint

methodology could not be exploited so far due to the paucity of known

edge-on spiral lenses. Exploiting the full SDSS-DR7 archive we have

identified a new sample of exactly these systems. We propose multi-color

HST imaging to confirm and measure a sample of twenty spiral lenses,

covering a range of bulge to disk ratios. By combining dynamical lensing

and stellar population information for this unique sample we will

deliver the first statistical constraints on halos and disk properties,

and a new stringent test of disk galaxy formation theories.

FGS 11945

Asteroseismology of Extrasolar Planet Host Stars

Detections of stellar oscillations, although a very demanding task in

terms of observing time, offers a return of more accurate knowledge

about the structure of stars than can be obtained in any other way. In

particular, detecting the 10-15 highest amplitude modes in solar-like

stars to signal-to-noise of just a few sigma each allows robust

constraints on the stellar density to <1%, and the stellar age to within

5-10% of its main sequence lifetime. Ten day observing runs using the

FGS as a photometer on any of the 5 best transiting planet systems would

enable these asteroseismology returns. From more precisely observed

transit shapes than can be obtained from the ground a completely

independent constraint on stellar density to ~1% can be obtained. The

long observation sets required for asteroseismology also provide an

excellent opportunity of detecting transits from other planets, e.g.

hypothesized inner -orbit Hot Earths, should any exist.

FGS 11943/11944

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 for 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 11797

Supplemental WFPC2 CYCLE 16 Intflat Linearity Check and Filter Rotation

Anomaly Monitor

Supplemental observations to 11029, to cover period from Aug 08 to SM4.

Intflat observations will be taken to provide a linearity check: the

linearity test consists of a series of intflats in F555W, in each gain

and each shutter. A combination of intflats, visflats, and earthflats

will be used to check the repeatability of filter wheel motions.

(Intflat sequences tied to decons, visits 1-18 in prop 10363, have been

moved to the cycle 15 decon proposal 11022 for easier scheduling.)

Note: long-exposure WFPC2 intflats must be scheduled during ACS anneals

to prevent stray light from the WFPC2 lamps from contaminating long ACS

external exposures.

Note: These are supplemental observations to cover June to SM4 (Oct 8

'08) + 6 months.

WFPC2 11796

WFPC2 Cycle 16 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument

monitors tied to decons: photometric stability check, focus monitor,

pre- and post-decon internals (bias, intflats, kspots, & darks), UV

throughput check, VISFLAT sweep, and internal UV flat check.

FGS 11788

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.

WFPC2 11590

Observing the IR Catastrophe in a Deflagration Type Ia Supernova

Our lack of understanding of Type Ia supernova (SN Ia) explosions limits

our confidence in their use for cosmology. While there is broad

agreement that these objects represent the explosions of white dwarfs,

the details of the explosion mechanism are not well-understood.

Recently, we have identified an internally homogeneous subclass of SNe

Ia whose photometric and spectroscopic peculiarities make them quite

distinct from normal SNe Ia. Models suggest we may be seeing the result

of an explosion with a subsonic burning front, called a deflagration. We

propose to test SN Ia models by obtaining late-time photometry for SN

2008A, a recent, nearby example of this subclass, using ACS and WFC3 on

HST. We will accurately measure the late-time photometric decline rate

and spectral energy distribution (SED). These observations will allow us

to test whether the ejecta contain the large amount of oxygen predicted

by certain models. We also aim to detect major evolution of the SED

expected due to the "IR catastrophe, " a change in the dominant cooling

mechanism in the ejecta, as generically predicted by models but only

hinted at by current observations.

WFPC2 11196

An Ultraviolet Survey 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 starbursts and creating/fueling central AGN. We

propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W} UV imaging of a

sample of 27 galaxies drawn from the complete IRAS Revised Bright Galaxy

Sample {RBGS} LIRGs sample and known, from our Cycle 14 B and I-band ACS

imaging observations, to have significant numbers of bright {23 < B < 21

mag} star clusters in the central 30 arcsec. The HST UV data will be

combined with previously obtained HST, Spitzer, and GALEX images to {i}

calculate the ages of the clusters as function of merger stage, {ii}

measure the amount of UV light in massive star clusters relative to

diffuse regions of star formation, {iii} assess the feasibility of using

the UV slope to predict the far-IR luminosity {and thus the star

formation rate} both among and within IR-luminous galaxies, and {iv}

provide a much needed catalog of rest- frame UV morphologies for

comparison with rest-frame UV images of high-z LIRGs and Lyman Break

Galaxies. These observations will achieve the resolution required to

perform both detailed photometry of compact structures and spatial

correlations between UV and redder wavelengths for a physical

interpretation our IRX-Beta results. The HST UV data, combined with the

HST ACS, Spitzer, Chandra, and GALEX observations of this sample, will

result in the most comprehensive study of luminous starburst galaxies to

date.

WFPC2 11013

Continued M31 Monitoring for Black Hole X-ray Nova

We have been carring out a Chandra (GO+GTO) and HST (GO) program to find

Black Hole X-ray Nova (BHXN) and their optical counterparts in M31 for

several years. To date we have found >2 dozen BHXN and 3 HST optical

counterparts for these BHXN. Our results suggest a rather high ratio of

BH to neutron star (NS) binaries, or a high duty cycle for the BHXN. We

propose to continue this program, with the goal of determining the

orbital period distribution and duty cycles of these BHXN. Current

results yield 3 orbital periods and 3 upper limits. Our proposed

observations will ~double the total number of periods and therefore

yield sufficient numbers to make a first approximation of the orbital

period distribution. The orbital period distribution is the fundamental

observable parameter any binary stellar evolution models must match, and

the duty cycle is very poorly known but directly influences the binary

lifetime. M31 is the only galaxy in which this extra-galactic study of

BHXN is feasible. Furthermore, the 2 HST observations will allow us to

estimate the orbital period of a single super-Eddington source.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

HSTARS:

11694 - At 052/01:12:56, GSAcq (2,3,2) scheduled from 052/01:09:14 -

           01:16:41 resulted in Fine Lock Back-up (2,0,2).

           0bservations possibly affected: Astrometry Proposal ID# 11943

11695 - REAcq (1,2,2) at 053/18:31:22 failed to RGA control with QF1STOPF

           and QSTOP flags set.

           Observations affected: WFPC 202 to 203, Proposal ID# 11986.

COMPLETED OPS REQUEST:

18404-0 - Uplink new FGS Alignment tables for 054 SMS @ 054/0019z

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL    

FGS GSacq               18                 18               

FGS REacq               22                 21  

OBAD with Maneuver 50                 50

SIGNIFICANT EVENTS:

The new FGS alignments were successfully uplinked tonight at the start

of the 054 SMS at 2009.054/00:20. The first Guide star acquisition on

the SMS was successful