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       # 4483

PERIOD COVERED: UT November 05, 2007 (DOY 309)

OBSERVATIONS SCHEDULED

ACS/SBC 11215

New Sightlines for the Study of Intergalactic Helium: Dozens of

High-Confidence, UV- Bright Quasars from SDSS/GALEX

The reionization of IGM helium is thought to have occurred at redshifts

of z=3 to 4. Detailed study of HeII Lyman-alpha absorption toward a

handful of QSOs at 2.7<z<3.3 demonstrated the high potential of such IGM

probes, but the critically small sample size limits confidence in

cosmological inferences. The requisite unobscured sightlines to high-z

are extremely rare, but SDSS provides 5800, z>3.1 QSOs potentially

suitable for HeII studies. We've cross-correlated SDSS quasars with

GALEX UV sources to obtain dozens of new, high confidence, candidate

sightlines {z=3.1-4.9} potentially useful for detailed HeII studies with

HST. We propose brief, 2-orbit reconnaissance ACS SBC prism exposures

toward each of the best dozen new quasars, to definitively verify UV

flux down to HeII. Our combined SDSS/GALEX selection insures a high

confirmation rate, as the quasars are already known to be UV bright in

GALEX. Our program will provide a statistical sample of HeII sightlines

extending to high redshift, enabling future long exposure follow-up

spectra with the SBC prism, or superb quality COS or STIS spectra after

SM4. Stacks of our prism spectra will also directly yield ensemble

information. Ultimately, the new sightlines will enable confident

measures of the spectrum and evolution of the ionizing background, the

evolution of HeII opacity, the epoch of helium reionization, and the

density of IGM baryons.

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.

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.

NIC1/NIC2/NIC3 11060

NICMOS Photometric Stability Monitoring

This NICMOS calibration proposal carries out photometric monitoring

observations during Cycle 15. The format is the same as the Cycle 14

version of the program {10725}, but a few modifications were made with

respect to the Cycle 12 program 9995 and Cycle 13 program 10381.

Provisions had to be made to adopt to 2-gyro mode {G191B2B was added as

extra target to provide target visibility through most of the year}.

Where before 4 or 7 dithers were made in a filter before we moved to the

next filter, now we observe all filters at one position before moving to

the next dither position. While the previous method was chosen to

minimize the effect of persistence, we now realize that persistence may

be connected to charge trapping and by moving through the filter such

that the count rate increases, we reach equilibrium more quickly between

charge being trapped and released. We have also increased exposure times

where possible to reduce the charge trapping non- linearity effects.

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 11341

Lower Luminosity AGNs at Cosmologically Interesting Redshifts: SEDs and

Accretion Rates of z~0.36 Seyferts

We propose a multiwavelength campaign to constrain the SEDs of Seyferts

at z~0.36. This epoch, corresponding to a look back time of 4 Gyrs, is

cosmologically interesting for studies of the coeval development of

black holes and their host galaxy bulges. Our sample, comprising 24

Seyferts, has unprecedented high quality Keck spectroscopy and HST

imaging already invested to extract host galaxy bulge properties,

estimate black hole masses, and separate nuclear and host optical

luminosities. To supplement and extend this successful program, we

request 93 ks of Chandra time (to measure the shape and power of the

AGN-only X-ray continuum), 11 hrs each of Spitzer and Gemini (to

constrain the dust temperature), and 7 orbits of HST (to determine the

nuclear luminosity for the final 7 objects).

NIC3/WFPC2 10921

Tangential Velocities of Objects in the Orion Nebula and Locating the

Embedded Outflow Sources.

The Orion Nebula is arguably the Rosetta Stone for studying a very young

star cluster and how the radiation and outflowing plasma from its stars

interact with ambient material. It has been the subject of numerous HST

imaging studies, which means that there is good opportunity for

determining tangential velocities by obtaining second epoch images

during Cycle 15, which may be the last cycle for which the WFPC2 is

available. These velocities in the plane-of-the-sky will allow us to

determine the patterns of outflow from micro-jets smaller than the Solar

System to jet driven shocks more than a parsec from their sources.

Combined with radial velocities, we'll obtain spatial velocities, which

are critical to determining where the embedded sources are located that

produce the numerous HH objects coming from the Orion-S and BN-KL

regions. We'll also be able to determine the physics that is operating

in the LL Ori type of outflows {where a bipolar jet is being distorted

by a slow wind coming from the nebula}. We will also be able to search

for runaway stars caused by the disintegration of young multiple-star

systems. All of this is possible because the long-time base of the WFPC2

and ACS observations allow a new level of astrometric precision to be

obtained and to be done efficiently by making coordinated parallel

observations with all images.

WFPC2 10900

Optical polarimetry of PSR B0540-69 and its synchrotron nebula.

Polarization measurements of pulsars and of their synchrotron nebulae

are uniquely able to provide deep insights into the highly magnetized

relativistic environment of young rotating neutron stars. Apart from the

radio band, pulsar polarization is best measured in the optical, for the

rare cases of detectable optical emission. One of the brightest pulsars

together with Crab {PSR B0531+21} and Vela {PSR B0833-45}, for which

optical polarization measurements support the newly developed two-pole

caustic model {TPC}, is PSR B0540-69 in the Large Magellanic Clouds,

often referred as the Crab Twin for their overall similarities in both

age and energetics. Together with the Crab, PSR B0540-69 is also the

only pulsar embedded in a synchrotron nebula visible at optical

wavelengths. We plan to observe PSR B0540-69 and its compact nebula {4

arcsec diameter} with the Advanced Camera for Surveys {ACS} and the Wide

Field Channel {WFC} detector using UV and visual polarization filters.

Thanks to the superb angular resolution of ACS, these observations will

allow us to spectacularly resolve the pulsar from its nebular

background, providing the first firm measure of the pulsar polarization

which will be crucial to assess, on a broader sample, the validity of

the TPC model with respect to other pulsars magnetosphere models. These

observations will also provide the first detailed polarization map of

the nebula, including the jet and the torus seen in our previous WFPC2

images.

WFPC2 10919

Eclipsing Binaries in the Local Group: II - Calibration of the Zeropoint

of the Cosmic Distance Scale and Fundamental Properties of Stars in M33

(uses NIC3)

The Great Spiral Galaxy in Triangulum {M33} is potentially a crucial

calibrator for the Cosmic Distance Scale, and thus for determining the

age and evolution of the Universe. M33 is viewed face-on, has a simple

geometry, large and diverse stellar populations, and morphologies

similar to our Galaxy and other more distant galaxies used for distance

determinations. Yet currently the M33 distance {d ~ 830 +/- 110 kpc}

still has measurement dispersions of 10-15%. We have demonstrated, in

our work on the LMC and M31 distances, that double-line eclipsing

binaries can serve as excellent "standard candles." Distances derived

from eclipsing binaries are basically geometric and essentially free

from many assumptions and uncertainties that plague other less direct

methods, such as metallicity differences and calibration zeropoints. The

absolute radii of the component stars of eclipsing binaries can be

determined to better than a few percent from the time- tested analyses

of their light and radial velocity curves. With accurate determinations

of radii, temperatures, and ISM absorption it is possible to determine

reliable distances. We are extending our program of using eclipsing

binaries as standard candles to determine an accurate distance to M33.

As a first step, we are proposing to carry out HST/ACS spectrophotometry

of a well suited ~19th mag ~O7 + ~O7 eclipsing binary system in M33 that

has been previously observed from the ground. HST/ACS prism/grism

low-resolution spectrophotometry {118-850 nm} is the only missing key

element of this program and is used to determine more reliable values

for T_eff, [Fe/H], and ISM extinction. These quantities, when combined

with the results from existing light and radial velocity curves for the

target, yield the stellar masses, radii, luminosities and, importantly,

the distance. The proposed HST/ACS program can be carried out

effectively with only 1 HST orbit. Based on our previous experience, we

expect to reduce the uncertainty of the M33 distance to better than

5-7%, thereby leading to a firmer calibration of the Cosmic Distance

Scale and the zeropoint of the Hubble Constant {Ho}.

WFPC2 11028

WFPC2 Cycle 15 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth

streak flats to improve the quality of pipeline flat fields for the

WFPC2 UV filter set. These Earth flats will complement the UV earth flat

data obtained during cycles 8-14.

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 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey of

a sample of 125 very X-ray luminous clusters in the redshift range

0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14

and Cycle15 these systems frequently exhibit strong gravitational

lensing as well as spectacular examples of violent galaxy interactions.

The proposed observations will provide important constraints on the

cluster mass distributions, the physical nature of galaxy-galaxy and

galaxy-gas interactions in cluster cores, and a set of optically bright,

lensed galaxies for further 8-10m spectroscopy. All of our primary

science goals require only the detection and characterization of

high-surface-brightness features and are thus achievable even at the

reduced sensitivity of WFPC2. Because of their high redshift and thus

compact angular scale our target clusters are less adversely affected by

the smaller field of view of WFPC2 than more nearby systems.

Acknowledging the broad community interest in this sample we waive our

data rights for these observations. Due to a clerical error at STScI our

approved Cycle15 SNAP program was barred from execution for 3 months and

only 6 observations have been performed to date - reinstating this SNAP

at Cycle16 priority is of paramount importance to reach meaningful

statistics.

WFPC2 11169

Collisions in the Kuiper belt

For most of the 15 year history of observations of Kuiper belt objects,

it has been speculated that impacts must have played a major role in

shaping the physical and chemical characteristics of these objects, yet

little direct evidence of the effects of such impacts has been seen. The

past 18 months, however, have seen an explosion of major new discoveries

giving some of the first insights into the influence of this critical

process. From a diversity of observations we have been led to the

hypotheses that: {1} satellite- forming impacts must have been common in

the Kuiper belt; {2} such impacts led to significant chemical

modification; and {3} the outcomes of these impacts are sufficiently

predictable that we can now find and study these impact-derived systems

by the chemical and physical attributes of both the satellites and the

primaries. If our picture is correct, we now have in hand for the first

time a set of incredibly powerful tools to study the frequency and

outcome of collisions in the outer solar system. Here we propose three

linked projects that would answer questions critical to the multiple

prongs of our hypothesis. In these projects we will study the chemical

effects of collisions through spectrophotometric observations of

collisionally formed satellites and through the search for additional

satellites around primaries with potential impact signatures, and we

will study the physical effects of impacts through the examination of

tidal evolution in proposed impact systems. The intensive HST program

that we propose here will allow us to fully test our new hypotheses and

will provide the ability to obtain the first extensive insights into

outer solar system impact processes.

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: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                         SCHEDULED      SUCCESSFUL

FGS GSacq                 10                 10                 

FGS REacq                 03                 03               

OBAD with Maneuver   26                 26        

SIGNIFICANT EVENTS: (None)