HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4617

PERIOD COVERED: 5am May 22 - 5am May 23, 2008 (DOY 143/0900z-144/0900z)

OBSERVATIONS SCHEDULED

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 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

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 DARKSs. 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 i

mages. Each observation will need its own CRMAP, as different SAA

passages leave different imprints on the NICMOS detectors.

NIC3 11195

Morphologies of the Most Extreme High-Redshift Mid-IR-luminous Galaxies

II: The `Bump' Sources

The formative phase of some of the most massive

galaxies may be extremely luminous, characterized by intense star- and

AGN-formation. Till now, few such galaxies have been unambiguously

identified at high redshift, and thus far we have been restricted to

studying the low-redshift ultraluminous infrared galaxies as possible

analogs. We have recently discovered a sample of objects which may

indeed represent this early phase in galaxy formation, and are

undertaking an extensive multiwavelength study of this population. These

objects are optically extremely faint {R>26} but nevertheless bright at

mid-infrared wavelengths {F[24um] > 0.5 mJy}. Mid-infrared spectroscopy

with Spitzer/IRS reveals that they have redshifts z~2, implying

luminosities ~1E13 Lsun. Their mid-IR SEDs fall into two broad, perhaps

overlapping, categories. Sources with brighter F[24um] exhibit power-law

SEDs and SiO absorption features in their mid-IR spectra characteristic

of AGN, whereas those with fainter F[24um] show a "bump" characteristic

of the redshifted 1.6um peak from a stellar population, and PAH emission

characteristic of starformation. We have begun obtaining HST images of

the brighter sources in Cycle 15 to obtain identifications and determine

kpc-scale morphologies for these galaxies. Here, we aim to target the

second class {the "bump" sources} with the goal of determining if these

constitute morphologically different objects, or simply a "low-AGN"

state of the brighter class. The proposed observations will help us

determine whether these objects are merging systems, massive obscured

starbursts {with obscuration on kpc scales!} or very reddened {locally

obscured} AGN hosted by intrinsically low-luminosity 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.

S/C 11320

NICMOS Focus Monitoring Cycle 16

This program is a version of the standard focus sweep used since cycle

7. It has been modified to go deeper and uses more narrow filters for

improved focus determination. A new source was added in Cycle 14 in

order to accommodate 2-gyro mode: the open cluster NGC1850. This source

is part of the current proposal. The old target, the open cluster

NGC3603, will be used whenever available and the new target used to fill

the periods when NGC3603 is not visible. Steps: a) Use refined target

field positions as determined from cycle 7 calibrations b) Use

MULTIACCUM sequences of sufficient dynamic range to account for defocus

c) Do a 17-point focus sweep, +/- 8mm about the PAM mechanical zeropoint

for each cameras 1 and 2, in 1.0mm steps. For NIC3 we step from -0.5mm

to -9.5mm relative to mechanical zero, in steps of 1.0mm. d) Use PAM X/Y

tilt and OTA offset slew compensations refined from previous focus

monitoring/optical alignment activities

WEPC2 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 11122

Expanding PNe: Distances and Hydro Models

We propose to obtain repeat narrowband images of a sample of eighteen

planetary nebulae {PNe} which have HST/WFPC2 archival data spanning time

baselines of a decade. All of these targets have previous high

signal-to-noise WFPC2/PC observations and are sufficiently nearby to

have readily detectable expansion signatures after a few years. Our main

scientific objectives are {a} to determine precise distances to these

PNe based on their angular expansions, {b} to test detailed and highly

successful hydrodynamic models that predict nebular morphologies and

expansions for subsamples of round/elliptical and axisymmetric PNe, and

{c} to monitor the proper motions of nebular microstructures in an

effort to learn more about their physical nature and formation

mechanisms. The proposed observations will result in high-precision

distances to a healthy subsample of PNe, and from this their expansion

ages, luminosities, CSPN properties, and masses of their ionized cores.

With good distances and our hydro models, we will be able to determine

fundamental parameters {such as nebular and central star masses,

luminosity, age}. The same images allow us to monitor the changing

overall ionization state and to search for the surprisingly

non-homologous growth patterns to bright elliptical PNe of the same sort

seen by Balick & Hajian {2004} in NGC 6543. Non-uniform growth is a sure

sign of active pressure imbalances within the nebula that require

careful hydro models to understand.

WFPC2 11176

Location and the Origin of Short Gamma-Ray Bursts

During the past decade extraordinary progress has been made in

determining the origin of long- duration gamma-ray bursts. It has been

conclusively shown that these objects derive from the deaths of massive

stars. Nonetheless, the origin of their observational cousins,

short-duration gamma-ray bursts {SGRBs} remains a mystery. While SGRBs

are widely thought to result from the inspiral of compact binaries, this

is a conjecture. A number of hosts of SGRBs have been identified, and

have been used by some to argue that SGRBs derive primarily from an

ancient population {~ 5 Gyr}; however, it is not known whether this

conclusion more accurately reflects selection biases or astrophysics.

Here we propose to employ a variant of a technique that we pioneered and

used to great effect in elucidating the origins of long-duration bursts.

We will examine the degree to which SGRB locations trace the red or blue

light of their hosts, and thus old or young stellar populations. This

approach will allow us to study the demographics of the SGRB population

in a manner largely free of the distance dependent selection effects

which have so far bedeviled this field, and should give direct insight

into the age of the SGRB progenitor population.

WFPC2 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still

largely an open problem in cosmology: how does the Universe evolve from

large linear scales dominated by dark matter to the highly non-linear

scales of galaxies, where baryons and dark matter both play important,

interacting, roles? To understand the complex physical processes

involved in their formation scenario, and why they have the tight

scaling relations that we observe today {e.g. the Fundamental Plane}, it

is critically important not only to understand their stellar structure,

but also their dark-matter distribution from the smallest to the largest

scales. Over the last three years the SLACS collaboration has developed

a toolbox to tackle these issues in a unique and encompassing way by

combining new non-parametric strong lensing techniques, stellar

dynamics, and most recently weak gravitational lensing, with

high-quality Hubble Space Telescope imaging and VLT/Keck spectroscopic

data of early-type lens systems. This allows us to break degeneracies

that are inherent to each of these techniques separately and probe the

mass structure of early-type galaxies from 0.1 to 100 effective radii.

The large dynamic range to which lensing is sensitive allows us both to

probe the clumpy substructure of these galaxies, as well as their

low-density outer haloes. These methods have convincingly been

demonstrated, by our team, using smaller pilot-samples of SLACS lens

systems with HST data. In this proposal, we request observing time with

WFPC2 and NICMOS to observe 53 strong lens systems from SLACS, to obtain

complete multi-color imaging for each system. This would bring the total

number of SLACS lens systems to 87 with completed HST imaging and

effectively doubles the known number of galaxy-scale strong lenses. The

deep HST images enable us to fully exploit our new techniques, beat down

low-number statistics, and probe the structure and evolution of

early-type galaxies, not only with a uniform data-set an order of

magnitude larger than what is available now, but also with a fully

coherent and self-consistent methodological approach!

WFPC2 11227

The orbital period for an ultraluminous X-ray source in NGC1313

The ultraluminous X-ray sources {ULXs} are extragalactic point sources

with luminosities that exceed the Eddington luminosity for conventional

stellar-mass black holes by factors of 10 - 100. It has been hotly

debated whether the ULXs are just common stellar-mass black hole sources

with beamed emission or whether they are sub-Eddington sources that are

firmly decide this question, one must obtain dynamical mass measurements

through photometric and spectroscopic monitoring of the secondaries of

these system. The crucial first step is to establish the orbital period

of a ULX, and arguably the best way to achieve this goal is by

monitoring its ellipsoidal light curve. The extreme ULX NGC1313 X-2

provides an outstanding target for an orbital period determination

because its relatively bright optical counterpart {V = 23.5} showed a

15% variation between two HST observations separated by three months.

This level of variability is consistent with that expected for a tidally

distorted secondary star. Here we propose a set of 20 imaging

observations with HST/WFPC2 to define the orbital period. This would be

the first photometric measurement of the orbital period of a ULX binary.

Subsequently, we will propose to obtain spectroscopic observations to

obtain its radial velocity amplitude and thereby a dynamical estimate of

its mass.

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 08 08

FGS REacq 07 07

OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)