Notice: Due to the conversion of some ACS WFC or HRC observations into

WFPC2, or NICMOS observations after the loss of ACS CCD science

capability in January, there may be an occasional discrepancy between a

proposal's listed (and correct) instrument usage and the abstract that

follows it.

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      # 4488

PERIOD COVERED: UT November , 2007 (DOY 317)

OBSERVATIONS SCHEDULED

ACS/SBC 11116

Exploring the Early FUV History of Cool Stars: Transition Regions at 30

Myr

Stellar magnetic activity derives from the so-called "dynamo," a

hydromagnetic interplay between overturning plasma motions and

differential rotation in stars cool enough to support significant

surface convection zones. The magnetic fields resulting from dynamo

action are in turn are responsible for a wide range of high-energy

emissions, including the spectacular outbursts called flares. Dynamo

powered magnetic activity is not confined solely to stars, but also must

occur, for example, in accretion disks of all descriptions, and in some

planets. A great deal is known about magnetic activity in middle-aged G

dwarfs like our Sun, thanks to its proximity. Less is known, however,

about the much younger stars, newly emerged from the T-Tauri stage. Yet,

it is during this phase that they reach the peak of their magnetic

activity, and subsidiary influences, such as the impact of ionizing

radiation and strong coronal winds on developing solar systems, also are

maximum. One of the key missing ingredients in our current understanding

are measurements of FUV emissions of such stars, to complement the

extensive collections of coronal {1-10 MK} X-ray measurements,

particularly from recent ROSAT, Chandra and XMM-Newton surveys. We

propose to conduct sensitive ACS/SBC prism ultraviolet spectroscopy of

selected fields in two young {30 Myr} Galactic clusters--IC 2391 and IC

2602--to inventory the key C IV emission index {~0.1 MK} over a much

larger and more diverse sample of coeval objects than has been possible

hitherto. A key question is whether the FUV emissions also suffer the

"saturation" and "super-saturation" at short rotation periods seen in

coronal X-rays, or whether they continue to rise in the fastest rotating

stars. The saturation behavior of the different temperature regimes

holds important clues to the organization of the surface active regions

on these very young stars, and should allow us to distinguish among

several competing models.

WFPC2 10583

Resolving the LMC Microlensing Puzzle: Where Are the Lensing Objects ?

We are requesting 32 HST orbits to help ascertain the nature of the

population that gives rise to the observed set of microlensing events

towards the LMC. The SuperMACHO project is an ongoing ground-based

survey on the CTIO 4m that has demonstrated the ability to detect LMC

microlensing events in real-time via frame subtraction. The improvement

in angular resolution and photometric accuracy available from HST will

allow us to 1} confirm that the detected flux excursions arise from LMC

source stars rather than extended objects {such as for background

supernovae or AGN}, and 2} obtain reliable baseline flux measurements

for the objects in their unlensed state. The latter measurement is

important to resolve degeneracies between the event timescale and

baseline flux, which will yield a tighter constraint on the microlensing

optical depth.

WFPC2 10766

A Deep X-ray Survey of the Small Magellanic Cloud

We request deep observations of 2 representative fields in the Small

Magellanic Cloud with Chandra and HST, with the primary goal of measuring

the luminosity function and space density of X-ray binaries and other

sources down to an unprecedented faint luminosity limit of 2x10E32

erg/s. This will be the faintest XLF ever obtained for any galaxy,

including our own. HST photometry to 24th magnitude in V and I filters

will identify the sources and provide Fx/Fopt, which will be vital in

quantifying the LMXB population and in measuring the properties of the

first coronally active stars ever detected in an external galaxy.

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 10854

Coronagraphic Imaging of Bright New Spitzer Debris Disks II.

Fifteen percent of bright main sequence stars possess dusty

circumstellar debris disks revealed by far-infrared photometry. These

disks are signposts of planetary systems: collisions among larger,

unseen parent bodies maintain the observed dust population against

losses to radiation pressure and P-R drag. Images of debris disks at

optical, infrared, and millimeter wavelengths have shown central holes,

rings, radial gaps, warps, and azimuthal asymmetries which indicate the

presence of planetary mass perturbers. Such images provide unique

insights into the structure and dynamics of exoplanetary systems.

Relatively few debris disks have been spatially resolved. Only thirteen

have ever been resolved at any wavelength, and at wavelengths < 10

microns {where subarcsec resolution is available}, only ten. Imaging of

many other debris disk targets has been attempted with various HST

cameras/coronagraphs and adaptive optics, but without success. The key

property which renders a debris disk observable in scattered light is

its dust optical depth. The ten disks imaged so far all have a dust

excess luminosity >~ 0.01% that of the central star; no disks with

smaller optical depths have been detected. Most main sequence stars

known to meet this requirement have already been observed, so future

progress in debris disk imaging depends on discovering additional stars

with large infrared excess. The Spitzer Space Telescope offers the best

opportunity in 20 years to identify new examples of high optical depth

debris disk systems. We propose to complete ACS coronagraphic imaging

followup of bright, new debris disks discovered during the first two

years of the Spitzer mission, by observing three additional targets in

Cycle 15. Our goal is to obtain the first resolved images of these disks

at ~3 AU resolution, define the disk sizes and orientations,and uncover

disk substructures indicative of planetary perturbations. The results

will open wider a window into the structure of planetary systems.

NIC2 11157

NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the

Stellar Mass Spectrum

Association of planetary systems with dusty debris disks is now quite

secure, and advances in our understanding of planet formation and

evolution can be achieved by the identification and characterization of

an ensemble of debris disks orbiting a range of central stars with

different masses and ages. Imaging debris disks in starlight scattered

by dust grains remains technically challenging so that only about a

dozen systems have thus far been imaged. A further advance in this field

needs an increased number of imaged debris disks. However, the technical

challege of such observations, even with the superb combination of HST

and NICMOS, requires the best targets. Recent HST imaging investigations

of debris disks were sample-limited not limited by the technology used.

We performed a search for debris disks from a IRAS/Hipparcos cross

correlation which involved an exhaustive background contamination check

to weed out false excess stars. Out of ~140 identified debris disks, we

selected 22 best targets in terms of dust optical depth and disk angular

size. Our target sample represents the best currently available target

set in terms of both disk brightness and resolvability. For example, our

targets have higher dust optical depth, in general, than newly

identified Spitzer disks. Also, our targets cover a wider range of

central star ages and masses than previous debris disk surveys. This

will help us to investigate planetary system formation and evolution

across the stellar mass spectrum. The technical feasibility of this

program in two-gyro mode guiding has been proven with on- orbit

calibration and science observations during HST cycles 13, 14, and 15.

WFPC2 11113

Binaries in the Kuiper Belt: Probes of Solar System Formation and

Evolution

The discovery of binaries in the Kuiper Belt and related small body

populations is powering a revolutionary step forward in the study of

this remote region. Three quarters of the known binaries in the Kuiper

Belt have been discovered with HST, most by our snapshot surveys. The

statistics derived from this work are beginning to yield surprising and

unexpected results. We have found a strong concentration of binaries

among low-inclination Classicals, a possible size cutoff to binaries

among the Centaurs, an apparent preference for nearly equal mass

binaries, and a strong increase in the number of binaries at small

separations. We propose to continue this successful program in Cycle 16;

we expect to discover at least 13 new binary systems, targeted to

subgroups where these discoveries can have the greatest impact.

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!

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

11059 – GSAcq (1,2,2) requires multiple attempts to achieve CT-DV

            OTA SE review of PTAS processing revealed that GSAcq (1,2,2) required

            multiple attempts to achieve CT DV on FGS1. (This occurred on day 314

            @19:42:53)

11060 - OBAD Failed Identification

           Upon acquisition of signal at 17:48:31 two 486 ESB messages were

           observed, 1806 ("T2G Open Loop Timeout"), and 1902 "OBAD Failed

           Identification".

           Dump of ESB messages reveals that these messages occurred at 16:37:38

           and 16:38:22, during the first of the two OBADs at 16:35:33, second OBAD

           at 16:43:28 was successful with RSS correction of 1632.73 arcseconds.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL      FAILURE TIMES

FGS GSacq               09                  09                                     

FGS REacq               04                  04                                                             

OBAD with Maneuver 26                  25                317/16:38z                   

SIGNIFICANT EVENTS: (None)