HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      # 4540

PERIOD COVERED: UT February 04, 2007 (DOY 035)

OBSERVATIONS SCHEDULED

ACS/SBC 10862

Comprehensive Auroral Imaging of Jupiter and Saturn during the

International Heliophysical Year

A comprehensive set of observations of the auroral emissions from

Jupiter and Saturn is proposed for the International Heliophysical Year

in 2007, a unique period of especially concentrated measurements of

space physics phenomena throughout the solar system. We propose to

determine the physical relationship of the various auroral processes at

Jupiter and Saturn with conditions in the solar wind at each planet.

This can be accomplished with campaigns of observations, with a sampling

interval not to exceed one day, covering at least one solar rotation.

The solar wind plasma density approaching Jupiter will be measured by

the New Horizons spacecraft, and a separate campaign near opposition in

May 2007 will determine the effect of large-scale variations in the

interplanetary magnetic field {IMF} on the Jovian aurora by

extrapolation from near-Earth solar wind measurements. A similar Saturn

campaign near opposition in Jan. 2007 will combine extrapolated solar

wind data with measurements from a wide range of locations within the

Saturn magnetosphere by Cassini. In the course of making these

observations, it will be possible to fully map the auroral footprints of

Io and the other satellites to determine both the local magnetic field

geometry and the controlling factors in the electromagnetic interaction

of each satellite with the corotating magnetic field and plasma density.

Also in the course of making these observations, the auroral emission

properties will be compared with the properties of the near-IR

ionospheric emissions {from ground-based observations} and non thermal

radio emissions, from ground-based observations for Jupiter’s decametric

radiation and Cassini plasma wave measurements of the Saturn Kilometric

Radiation {SKR}.

WFPC2 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 routine internal monitor for

WFPC2, to be run weekly to monitor the health of the cameras. A variety

of internal exposures are obtained in order to provide a monitor of the

integrity of the CCD camera electronics in both bays {both gain 7 and

gain 15 -- to test stability of gains and bias levels}, a test for

quantum efficiency in the CCDs, and a monitor for possible buildup of

contaminants on the CCD windows. These also provide raw data for

generating annual super-bias reference files for the calibration

pipeline.

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/ACS/SBC 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-lumnious 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

radtion at z<1, requiring substantial evolution in the processes within

Lyman break galaxies which allow large escape fractions at high

redshift.

WFPC2 11022

WFPC2 Cycle 15 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.

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly

Monitor

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 xxxx 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.

WFPC2 11070

WFPC2 CYCLE 15 Standard Darks - part II

This dark calibration program obtains dark frames every week in order to

provide data for the ongoing calibration of the CCD dark current rate,

and to monitor and characterize the evolution of hot pixels. Over an

extended period these data will also provide a monitor of radiation

damage to the CCDs.

WFPC2 11084

Probing the Least Luminous Galaxies in the Local Universe

We propose to obtain deep color-magnitude data of eight new Local Group

galaxies which we recently discovered: Andromeda XI, Andromeda XII, and

Andromeda XIII {satellites of M31}; Canes Venatici I, Canes Venatici II,

Hercules, and Leo IV {satellites of the Milky Way}; and Leo T, a new

"free-floating" Local Group dwarf spheroidal with evidence for recent

star formation and associated H I gas. These represent the least

luminous galaxies known at *any* redshift, and are the only accessible

laboratories for studying this extreme regime of galaxy formation. With

deep WFPC-2 F606W and F814W pointings at their centers, we will

determine whether these objects contain single or multiple age stellar

populations, as well as whether these objects display a range of

metallicities.

WFPC2 11178

Probing Solar System History with Orbits, Masses, and Colors of

Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens a

window into dynamical conditions in the protoplanetary disk where they

formed as well as the history of subsequent events which sculpted the

outer Solar System and emplaced them onto their present day heliocentric

orbits. To date, at least 47 TNBs have been discovered, but only about a

dozen have had their mutual orbits and separate colors determined,

frustrating their use to investigate numerous important scientific

questions. The current shortage of data especially cripples scientific

investigations requiring statistical comparisons among the ensemble

characteristics. We propose to obtain sufficient astrometry and

photometry of 23 TNBs to compute their mutual orbits and system masses

and to determine separate primary and secondary colors, roughly tripling

the sample for which this information is known, as well as extending it

to include systems of two near-equal size bodies. To make the most

efficient possible use of HST, we will use a Monte Carlo technique to

optimally schedule our observations.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS,

GOODS, etc.} are producing spectacular results for galaxy masses roughly

below a transition mass M~10^13 Mo. The observed lens properties and

their evolution up to z~0.2, consistent with numerical simulations, can

be described by isothermal elliptical potentials. In contrast, modeling

of giant arcs in X-ray luminous clusters {halo masses M >~10^13 Mo}

favors NFW mass profiles, suggesting that dark matter halos are not

significantly affected by baryon cooling. Until recently, lensing

surveys were neither deep nor extended enough to probe the intermediate

mass density regime, which is fundamental for understanding the assembly

of structures. The CFHT Legacy Survey now covers 125 square degrees, and

thus offers a large reservoir of strong lenses probing a large range of

mass densities up to z~1. We have extracted a list of 150 strong lenses

using the most recent CFHTLS data release via automated procedures.

Following our first SNAPSHOT proposal in cycle 15, we propose to

continue the Hubble follow-up targeting a larger list of 130 lensing

candidates. These are intermediate mass range candidates {between

galaxies and clusters} that are selected in the redshift range of 0.2-1

with no a priori X-ray selection. The HST resolution is necessary for

confirming the lensing candidates, accurate modeling of the lenses, and

probing the total mass concentration in galaxy groups up to z~1 with the

largest unbiased sample available to date.

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)