Email distribution of the HST Daily Report will cease on ~10/15/10. The

Daily Report can now be found, and will continue to appear at:

http://www.stsci.edu/hst beneath the heading "HST Daily Report."

Reports for the prior "Zulu Day," 00:00:00 to 23:59:59 Universal Time,

will normally be posted by early afternoon, Eastern Time.

From the switchover date forward, Daily Reports will be issued 7 days a

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HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5199-#5202

PERIOD COVERED: 8:00pm October 7 - 7:59pm October 11, 2010 (DOY 281/00:00z-284/23:59z)

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

12459 - GSAcq(1,2,1) scheduled at 282/08:45:01z and REAcq(1,2,1)scheduled at

           282/09:57:21z both resulted in fine lock backup (1,0,1).

           Observations possibly affected: ACS 77-82 Proposal ID#11575

12460 - GSAcq(2,1,1) scheduled at 282/11:16:52z failed due to search radius limit

           exceeded on FGS 1 and FGS 2.

           Observations affected: ACS 83 Proposal#12210; WFC3 138 Proposal ID#12380

12461 - REAcq(2,3,3) scheduled at 283/10:16:45 failed due to search radius

           limit exceeded on FGS 2

           Observations affected: ACS 114-117, WFC3 189-190 Proposal ID#12061

12462 - GSAcq(1,0,1) scheduled at 283/11:53:12z failed due to search radius limit exceeded on FGS 1.

           and REAcq(1,0,1) scheduled at 283/13:38:26z failed due to SRLEX on FGS 1

           Observations affected: WFC3 191-194 Proposal ID#12061; ACS 118-122 Proposal ID#12061

12463 - GSAcq(1,2,1) at 283/15:20:54z and REAcq(1,2,1) scheduled at 283/16:42:54z,

           283/18:18:47z, and at 283/19:54:40z  all failed due to search radius

           limit exceeded on FGS 2.

           Observations affected: WFC3 196-214 Proposal ID#12181; WFC3 215 Proposal ID#12380

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED   SUCCESSFUL

FGS GSAcq               45               42

FGS REAcq               22               17

OBAD with Maneuver 35               35

SIGNIFICANT EVENTS: (None)

OBSERVATIONS SCHEDULED:

WFC3/IR 12380

Guard Darks

The goal of the Guard Dark program is to collect WFC3/IR dark current

data prior to each visit in two of the Multi-Cycle Treasury (MCT)

programs in Cycle 18. By scheduling a dark current observation between

the last pre-MCT observation and the first MCT visit, we will be able to

measure any residual persistent signal resulting from the former which

may affect the latter.

WFC3/UV 12345

UVIS Long Darks Test

Darks during SMOV showed a systematically lower global dark rate as well

as lower scatter when compared to the Cycle 17 darks. Those two sets of

exposures differ in exposure time - 1800 sec during SMOV and 900 sec

during Cycle 17. Hypothetically, the effect could be caused by

short-duration stray light, say ~500-sec in duration. During the latter

part of Cycle 17, operation of WFC3 was changed to additionally block

the light path to the detector with the CSM. This program acquires a

small number of darks at the longer SMOV exposure times (1800 sec) in

order to check whether the effect repeats in the new operating mode.

WFC3/UV 12344

Cycle 18: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the

UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.

Initially found via an unexpected bowtie-shaped feature in flatfield

ratios, subsequent lab tests on similar e2v devices have since shown

that it is also present as simply an overall offset across the entire

CCD, i.e., a QE offset without any discernable pattern. These lab tests

have further revealed that overexposing the detector to count levels

several times full well fills the traps and effectively neutralizes the

bowtie. Each visit in this proposal acquires a set of three 3x3 binned

internal flatfields: the first unsaturated image will be used to detect

any bowtie, the second, highly-exposed image will neutralize the bowtie

if it is present, and the final image will allow for verification that

the bowtie is gone.

WFC3/IR 12307

A public SNAPSHOT Survey of Gamma-ray Burst Host Galaxies

We propose to conduct a public infrared survey of the host galaxies of

Swift selected gamma-ray bursts (GRBs) at z<3. By obtaining deep,

diffraction limited imaging in the IR we will complete detections for

the host galaxies, and in concert with our extensive ground based

afterglow and host programmes will compile a detailed catalog of the

properties of high-z galaxies selected by GRBs. In particular these

observations will enable us to study the colours, luminosities and

morphologies of the galaxies. This in turn informs studies of the nature

of the progenitors and the role of GRBs as probes of star formation

across cosmic history. Ultimately it provides a product of legacy value

which will greatly complement further studies with next generation

facilities such as ALMA and JWST.

COS/NUV/FUV 12299

Spectroscopic Signatures of Binary and Recoiling Black Holes

We propose to obtain UV the spectra of the Ly-alpha and Mg II lines of

13 SDSS quasars whose H-beta lines are offset by 1000-4000 km/s from

their systemic redshifts. Such lines have been suggested to originate in

recoiling or close binary black holes. However these interpretations are

not unique and UV spectroscopy, possible only with the HST, can

discriminate between competing possibilities. Identifying such systems

is extremely important in the context of scenarios for galaxy formation

and evolution and in view of recent predictions from numerical

relativity. Close binary black holes represent an apparently inevitable

stage in the merger of two massive galaxies. The subsequent merger of

the members of the binary is expected to produce a recoiling black hole

in some fraction of cases. Thus, the census of such systems, their

environments, and hosts can constrain some of the more uncertain

parameters in evolutionary models. But before we can find them in any

numbers, we need to evaluate the candidates known so far. This is the

goal of our proposal.

STIS/CC 12291

STIS coronagraphy of Spitzer-selected debris disks

Debris disks trace the structure, dynamic, and formation of exoplanetary

systems. In the cases of Fomalhaut and HR 8799 exoplanets have been

imaged at the locations expected from the disk structures. Fifteen

percent of 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 Poynting-Robertson 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. Only twenty have been spatially

resolved at any wavelength, and at wavelengths <10 microns (where

subarcsec resolution is available), only fifteen. Imaging of dozens of

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 sixteen disks imaged so far all have an

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

smaller optical depths have been detected. Most nearby, 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 provided

the best opportunity in 20 years to identify new examples of high

optical depth debris disk systems. We have conducted detailed imaging

simulations of debris disks newly identified by Spitzer since 2007,

including size, surface brightness, and contrast estimates. From these

we have identified ten targets whose disks should be detectable with the

STIS coronagraph in roll-subtracted images. In terms of their

detectability and resolvability to HST, these are the best remaining

targets to emerge from the now-complete Spitzer photometric surveys of

nearby main sequence stars. Our goals are 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.

WFC3/IR 12286

Hubble Infrared Pure Parallel Imaging Extragalactic Survey (HIPPIES)

WFC3 has demonstrated its unprecedented power in probing the early

universe. Here we propose to continue our pure parallel program with

this instrument to search for LBGs at z~6--8. Our program, dubbed as the

Hubble Infrared Pure Parallel Imaging Extragalactic Survey ("HIPPIES"),

will carry on the HST pure parallel legacy in the new decade. We request

205 orbits in Cycle-18, which will spread over ~ 50 high Galactic

latitude visits (|b|>20deg) that last for 3 orbits and longer, resulting

a total survey area of ~230 square arcmin. Combining the WFC3 pure

parallel observations in Cycle-17, HIPPIES will complement other

existing and forthcoming WFC3 surveys, and will make unique

contributions to the study in the new redshift frontier because of the

randomness of the survey fields. To make full use of the parallel

opportunities, HIPPIES will also take ACS parallels to study LBGs at

z~5--6. Being a pure parallel program, HIPPIES will only make very

limited demand on the scarce HST resources, but will have potentially

large scientific returns. As in previous cycle, we waive all proprietary

data rights, and will make the enhanced data products public in a timely

manner.

(1) The WFC3 part of HIPPIES aims at the most luminous LBG population at

z~8 and z~7. As its survey fields are random and completely

uncorrelated, the number counts of the bright LBGs from HIPPIES will be

least affected by the "cosmic variance", and hence we will be able to

obtain the best constraint on the bright-end of the LBG luminosity

function at z~8 and 7. Comparing the result from HIPPIES to the

hydrodynamic simulations will test the input physics and provide insight

into the nature of the early galaxies. (2) The z~7--8 candidates from

HIPPIES, most of which will be the brightest ones that any surveys would

be able to find, will have the best chance to be spectroscopically

confirmed at the current 8--10m telescopes. (3) The ACS part of HIPPIES

will produce a significant number of candidate LBGs at z~5 and z~6 per

ACS field. Combining with the existing, suitable ACS fields in the HST

archive, we will be able to utilize the random nature of the survey to

quantify

the cosmic variance and to measure the galaxy bias at z~5--6, and

therefore the galaxy halo masses at these redshifts. (4) We will also

find a large number of extremely red, old galaxies at intermediate

redshifts, and the fine spatial resolution offered by the WFC3 will

enable us constrain their formation history based on the study of their

morphology, and hence shed light on their connection to the very early

galaxies in the universe.

WFC3/IR 12283

WFC3 Infrared Spectroscopic Parallel Survey (WISP): A Survey of Star

Formation Across Cosmic Time

We will use the unique power of WFC3 slitless spectroscopy to measure

cosmic star formation across its peak epoch. The broad, continuous,

spectral coverage of the G102 and G141 grisms provides the best

currently feasible measurement of the star formation rate continuously

from 0.5<z<2.5, over which ground-based searches are severely limited.

Our Cycle 17 pure-parallel grism program has proven efficient for

identifying line emission from galaxies across this large fraction of

cosmic time. With less than two months of WFC3 observing completed, our

new measurements have more than doubled the sample of emission-line

galaxies that we found over the entire NICMOS Parallel Grism program. We

propose to extend this cost-effective WFC3 Survey by using 280 orbits of

pure parallel grism spectroscopy in 50 deep (4-5 orbit) fields with both

G102 and G141, and 40 shallow (2-3 orbit) fields with G141 alone. This

will complete a sample of 2000-3000 emission line galaxies in the

"redshift desert" and search for serendipitous Lya emitters at z>5.5.

Our primary science goals are: (1) Measure ratios of bright emission

lines ([OII], [OIII], Ha, and Hb) in a substantial fraction of these

galaxies, thereby estimating dust and metallicity evolution in a sample

of galaxies that is not biased by photometric selection. (2) Derive an

extinction-corrected Ha luminosity function, with a 20 times larger

sample than our previous NICMOS results. (3) Measure the

mass-metallicity relation at crucial intermediate redshifts, with the

support of our ongoing ground-based, follow-up, observing program (4)

Determine the spectroscopic close pair fraction in this sample, in order

to constrain hierarchal merging models (5) Uncover a new sample of

obscured AGN at these redshifts and, (6) Use the Balmer break diagnostic

to constrain the ages of continuum detected sources down to H = 25.

As a bonus, these observations will be sensitive to Lya emission at

z>5.5, taking advantage of continuous spectral coverage to observe large

volumes for luminous galaxies at the highest redshifts. Over Cycles 17

and 18, we expect to detect 5-20 LAEs over redshifts spanning 5.5 < z <

7.5. These observations will likely place the most stringent constraint

on the numbers of z>6.5 Lya emitters until JWST. We are waiving all

proprietary rights to our data and will make high-level data products

available through the ST/ECF.

WFC3/IR 12251

The First Characterization of a Super-Earth Atmosphere

Our team recently discovered the first transiting super-Earth exoplanet

whose atmosphere can be studied with HST. GJ1214b is a 2.7 Earth radius,

6.6 Earth mass exoplanet that transits a low-mass M dwarf located a mere

13 pc away. With only a mass and radius known, structural models show

that GJ1214b may either have an extended H-rich envelope or consist of a

body that is mostly water, surrounded by a thin, H-poor atmosphere. We

propose to observe the planet in transit with WFC3 IR's G141 grism to

measure its transmission spectrum between 1.1 and 1.7 microns. Our

primary science goal is to determine the super-Earth's atmospheric scale

height, thus distinguishing between its possible bulk compositions. The

summed light curve will permit a search for transiting moons around

GJ1214b the size of Ganymede. Among the presently known transiting

exoplanets, GJ1214b is the smallest, coolest, most Earth-like planet

that has a substantial atmosphere. Fortunately, the small radius of the

star means studying GJ1214b's atmosphere requires no better precision

than has already been demonstrated by HST observations of transiting hot

Jupiters.

COS/NUV/FUV/WFC3/UV 12248

How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and

Galactic Winds Below L*

One of the most vexing problems in galaxy formation concerns how gas

accretion and feedback influence the evolution of galaxies. In high mass

galaxies, numerical simulations predict the initial fuel is accreted

through 'cold' streams, after which AGN suppress star formation to leave

galaxies red and gas-poor. In the shallow potential wells that host

dwarf galaxies, gas accretion can be very efficient, and "superwinds"

driven either by hot gas expelled by SNe or momentum imparted by SNe and

hot-star radiation are regarded as the likely source(s) of feedback.

However, major doubts persist about the physics of gas accretion, and

particularly about SN-driven feedback, including their scalings with

halo mass and their influence on the evolution of the galaxies. While

"superwinds" are visible in X-rays near the point of their departure,

they generally drop below detectable surface-brightness limits at ~ 10

kpc. Cold clumps in winds can be detected as blue-shifted absorption

against the galaxy's own starlight, but the radial extent of these winds

are difficult to constrain, leaving their energy, momentum, and ultimate

fate uncertain. Wind prescriptions in hydrodynamical simulations are

uncertain and at present are constrained only by indirect observations,

e.g. by their influence on the stellar masses of galaxies and IGM

metallicity. All these doubts lead to one conclusion: we do not

understand gas accretion and feedback because we generally do not

observe the infall and winds directly, in the extended gaseous halos of

galaxies, when it is happening. To do this effectively, we must harness

the power of absorption-line spectroscopy to measure the density,

temperature, metallicity, and kinematics of small quantities of diffuse

gas in galaxy halos. The most important physical diagnostics lie in the

FUV, so this is uniquely a problem for HST and COS. We propose new COS

G130M and G160M observations of 41 QSOs that probe the gaseous halos of

44 SDSS dwarf galaxies well inside their virial radii. Using sensitive

absorption-line measurements of the multiphase gas diagnostics Lya,

CII/IV, Si II/III/IV, and other species, supplemented by optical data

from SDSS and Keck, we will map the halos of galaxies with L = 0.02 -

0.3 L*, stellar masses M* = 10^(8-10) Msun, over impact parameter from

15 - 150 kpc. These observations will directly constrain the content and

kinematics of accreting and outflowing material, provide a concrete

target for simulations to hit, and statistically test proposed galactic

superwind models. These observations will also inform the study of

galaxies at high z, where the shallow halo potentials that host dwarf

galaxies today were the norm. These observations are low-risk and

routine for COS, easily schedulable, and promise a major advance in our

understanding of how dwarf galaxies came to be.

WFC3/UV/IR 12234

Differentiation in the Kuiper belt: a Search for Silicates on Icy

Bodies.

We currently have a large on-going program (Go Program 11644, 120

orbits) to exploit the superb stability and photometric characteristics

of HST and the broad range in wavelength coverage of the WFC3 to make

broad-band vis/IR spectral observations of a large sample of Kuiper belt

objects. Though the survey is currently only ~50% complete, the quality

and unprecedented signal-to-noise of these observations has revealed the

existence of a previously undiscovered spectral variability not

explainable within our current understanding of these objects.

A possible explanation for this variability is that with this faint set

of Kuiper belt objects, we are beginning to see the difference between

larger differentiated objects and smaller non-differentiated objects.

Its seems that the small and likely undifferentiated objects are

exhibiting silicate features that affect our photometry - features not

exhibited by the icy mantles of larger icy bodies.

We propose a small add-on survey to dramatically increase the scientific

results of our large program. The proposed observations will use the

proven capabilities of WFC3 to make broad and narrow-band photometric

observations to detect spectral features in the 1.0-1.3 micron range of

a small subset of our sources. The 13 targets have been carefully

selected to cover the range of spectral variability detected in our

large program as well as sample the entire dynamical range and physical

sizes of these targets. These observations will allow the identification

of undifferentiated Kuiper belt objects by detection of their silicate

features. As a probe for differentiation, these observations could

constrain the natal locations of different Kuiper belt classes, a

constraint currently unavailable to formation models. This small set of

observations will allow the calibration of the spectral variability seen

in our large program, and drastically enhance the scientific output of

our full Cycle 17 sample.

WFC3/UV 12215

Searching for the Missing Low-Mass Companions of Massive Stars

Recent results on binary companions of massive O stars appear to

indicate that the distribution of secondary masses is truncated at low

masses. It thus mimics the distribution of companions of G dwarfs and

also the Initial Mass Function (IMF), except that it is shifted upward

by a factor of 20 in mass. These results, if correct, provide a

distribution of mass ratios that hints at a strong constraint on the

star-formation process. However, this intriguing result is derived from

a complex simulation of data which suffer from observational

incompleteness at the low-mass end.

We propose a snapshot survey to test this result in a very direct way.

HST WFC3 images of a sample of the nearest Cepheids (which were formerly

B stars of ~5 Msun) will search for low-mass companions down to M

dwarfs. We will confirm any companions as young stars, and thus true

physical companions, through follow-up Chandra X-ray images. Our survey

will show clearly whether the companion mass distribution is truncated

at low masses, but at a mass much higher than that of the IMF or G

dwarfs.

ACS/WFC 12210

SLACS for the Masses: Extending Strong Lensing to Lower Masses and

Smaller Radii

Strong gravitational lensing provides the most accurate possible

measurement of mass in the central regions of early-type galaxies

(ETGs). We propose to continue the highly productive Sloan Lens ACS

(SLACS) Survey for strong gravitational lens galaxies by observing a

substantial fraction of 135 new ETG gravitational-lens candidates with

HST-ACS WFC F814W Snapshot imaging. The proposed target sample has been

selected from the seventh and final data release of the Sloan Digital

Sky Survey, and is designed to complement the distribution of previously

confirmed SLACS lenses in lens-galaxy mass and in the ratio of Einstein

radius to optical half-light radius. The observations we propose will

lead to a combined SLACS sample covering nearly two decades in mass,

with dense mapping of enclosed mass as a function of radius out to the

half-light radius and beyond. With this longer mass baseline, we will

extend our lensing and dynamical analysis of the mass structure and

scaling relations of ETGs to galaxies of significantly lower mass, and

directly test for a transition in structural and dark-matter content

trends at intermediate galaxy mass. The broader mass coverage will also

enable us to make a direct connection to the structure of well-studied

nearby ETGs as deduced from dynamical modeling of their line-of-sight

velocity distribution fields. Finally, the combined sample will allow a

more conclusive test of the current SLACS result that the intrinsic

scatter in ETG mass-density structure is not significantly correlated

with any other galaxy observables. The final SLACS sample at the

conclusion of this program will comprise approximately 130 lenses with

known foreground and background redshifts, and is likely to be the

largest confirmed sample of strong-lens galaxies for many years to come.

ACS/WFC 12209

A Strong Lensing Measurement of the Evolution of Mass Structure in Giant

Elliptical Galaxies

The structure and evolution of giant elliptical galaxies provide key

quantitative tests for the theory of hierarchical galaxy formation in a

cold dark matter dominated universe. Strong gravitational lensing

provides the only direct means for the measurement of individual

elliptical galaxy masses beyond the local universe, but there are

currently no large and homogeneous samples of strong lens galaxies at

significant cosmological look-back time. Hence, an accurate and

unambiguous measurement of the evolution of the mass-density structure

of elliptical galaxies has until now been impossible. Using

spectroscopic data from the recently initiated Baryon Oscillation

Spectroscopic Survey (BOSS) of luminous elliptical galaxies at redshifts

from approximately 0.4 to 0.7, we have identified a large sample of

high-probability strong gravitational lens candidates at significant

cosmological look-back time, based on the detection of emission-line

features from more distant galaxies along the same lines of sight as the

target ellipticals. We propose to observe 45 of these systems with the

ACS-WFC in order to confirm the incidence of lensing and to measure the

masses of the lens galaxies. We will complement these lensing mass

measurements with stellar velocity dispersions from ground-based

follow-up spectroscopy. In combination with similar data from the Sloan

Lens ACS (SLACS) Survey at lower redshifts, we will directly measure the

cosmic evolution of the ratio between lensing mass and dynamical mass,

to reveal the structural explanation for the observed size evolution of

elliptical galaxies (at high mass). We will also measure the evolution

of the logarithmic mass-density profile of massive ellipticals, which is

sensitive to the details of the merging histories through which they are

assembled. Finally, we will use our lensing mass-to-light measurements

to translate the BOSS galaxy luminosity function into a mass function,

and determine its evolution in combination with data from the original

Sloan Digital Sky Survey.

WFC3/IR 12197

Evolution in the Size-Luminosity Relation of HII regions in

Gravitationally-lensed galaxies

The gravitational magnification of distant galaxies by foreground

clusters has enabled the first measurement of the size-luminosity

relation for HII regions at redshift z~2-5. A significant offset is seen

in this relation with respect to that determined locally. This

evolutionary trend has been interpreted as possible evidence for a

dfferent mode of star formation in the early universe. To test this

hypothesis, we propose to image a sample of 7 lensed galaxies at

intermediate redshifts, z~1.0-1.5, carefully chosen so that the Halpha

emission falls precisely within an appropriate narrow-band fiter with

WFC3/IR. As each galaxy is magnified by a significant factor, this will

enable us to resolve and measure the luminosities of ~50 individual HII

regions as small as 50 pc to a star formation rate limit of 0.015

Mo/year. By tracking the size-luminosity relation over the full redshift

range from 0 to 5, we can differentiate between various explanations

proposed for the change in this fundamental relationship.

WFC3/IR 12181

The Atmospheric Structure of Giant Hot Exoplanets

Characterization of close-in giant exoplanets has proceeded rapidly over

the past few years, due largely to Spitzer and HST observations in

transiting systems. Low resolution thermal emission spectra of over two

dozen planets have been measured by Spitzer, and HST observations of a

few key planets have indicated unusual molecular abundances via

transmission spectroscopy. However, current models for the atmospheric

structure of these worlds exhibit degeneracies wherein different

combinations of temperature and molecular abundance profiles can fit the

same Spitzer data for each planet. Fortunately, the advent of the IR

capability on HST/WFC3 allows us to solve this major problem in

exoplanet science. We propose to inaugurate a Large HST program that is

scientifically complementary to Spitzer, Kepler, and CoRoT exoplanet

results.

We will obtain transmission spectroscopy of the 1.4-micron water band in

a sample of 13 planets, using the G141 grism on WFC3. Among the abundant

molecules, only water absorbs at this wavelength, and our measurement of

water abundance will enable us to break the degeneracies in the Spitzer

results with minimal model assumptions. We will also use the G141 grism

to observe secondary eclipses for 7 very hot giant exoplanets at

1.5-microns, including several bright systems in the Kepler and CoRoT

fields. The strong temperature sensitivity of the thermal continuum at

1.5-microns provides high leverage on atmospheric temperature for these

worlds, again helping to break degeneracies in interpreting the Spitzer

data. Moreover, our precise eclipse photometry, in combination with

extant Spitzer data, will enable us to extrapolate the thermal continuum

to optical wavelengths. Kepler and CoRoT teams will be thereby able to

subtract the thermal contribution from their increasingly precise

measurements of optical eclipses, and measure, or place extremely

stringent limits on, the albedo of these exotic worlds.

COS/NUV/FUV 12178

Spanning the Reionization History of IGM Helium: a Highly Efficient

Spectral Survey of the Far- UV-Brightest Quasars

The reionization of IGM helium likely occurred at redshifts of z=3 to 4.

Detailed studies of HeII Ly-alpha absorption toward a handful of quasars

at 2.7<z<3.3 confirm the potential of such IGM probes, but the small

sample and redshift range limited confidence in cosmological inferences.

The requisite unobscured sightlines to high redshift are extremely rare;

but we've cross-correlated 10, 000 z>2.8 SDSS DR7 (and other) quasars

with GALEX GR4/5, to identify 630 candidates potentially useful for HST

HeII studies. Our cycle 15-16 HST trials confirm our approach, verifying

twenty new HeII quasars at unprecedented 40% efficiency. We propose to

complete the first efficient (80% with refinements) survey for HeII

quasars, via reconnaissance (~1 orbit) COS spectra of a highly select

subset of 17 SDSS/GALEX quasars at 2.7<z<3.8. Along with past work, this

program will yield 3-4 of the brightest far-UV HeII sightlines within

each of 10-12 redshift bins spanning 2.7<z<3.8, enabling a community

sample suitable for detailed spectral follow-up with HST. Herein, we

will also directly obtain quality UV spectral stacks within each

redshift bin to trace the reionization history of IGM helium; such

spectral stacks average over cosmic variance and individual object

pathology. Our high-yield HeII sightline sample and spectral stacks will

enable confident conclusions about the IGM baryon density, the spectrum

and evolution of the ionizing background, the evolution of HeII opacity,

and the epoch of helium reionization.

ACS/WFC 12166

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful HST/ACS SNAPshot

survey of a sample of 123 very X-ray luminous clusters in the redshift

range 0.3-0.7, detected and compiled by the MACS cluster survey. As

demonstrated by dedicated HST observations of the 12 most distant MACS

clusters (GO-09722) as well as by the MACS SNAPshots of an additional 25

obtained with ACS so far in Cycles 14 and 15, these systems frequently

exhibit strong gravitational lensing as well as spectacular examples of

violent galaxy evolution. A large number of additional MACS SNAPs have

since been obtained with WFPC2, leading to the discovery of several more

powerful cluster lenses. The dramatic loss, however, of depth,

field-of-view, and angular resolution compared to ACS led to

significantly reduced scientific returns, underlining the need for ACS

for this project. The proposed observations will provide important

constraints on the cluster mass distributions, on the physical nature of

! galaxy-galaxy and galaxy-gas interactions in cluster cores, and will

yield a set of optically bright, lensed galaxies for further 8-10m

spectroscopy. For those of our targets with existing ACS SNAPshot

images, we propose SNAPshots in the WFC3 F110W and F140W passbands to

obtain colour information that will greatly improve the secure

identification of multiple-image systems and may, in the form of F606W

or F814W dropouts, lead to the lensing-enabled discovery of very distant

galaxies at z>5. Acknowledging the broad community interest in this

sample (16 of the 25 targets of the approved MCT cluster program are

MACS discoveries) we waive our data rights for these observations.

This proposal is an updated and improved version of our successful Cycle

15 proposal of the same title. Alas, SNAP-10875 collected only six

snapshots in the F606W or F814W passbands, due to, first, a clerical

error at STScI which caused the program to be barred from execution for

four months and, ultimately, the failure of ACS. With ACS restored, and

WFC3 providing additional wavelength and redshift leverage, we wish to

resume this previously approved project.

WFC3/IR/WFC/ACS/UV 12061

Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-South

Field, Early Visits of SNe Search

This survey will document the first third of galactic evolution from z=8

to 1.5 and test for evolution in the properties of Type Ia supernovae to

z~2 by imaging more than 250, 000 galaxies with WFC3/IR and ACS. Five

premier multi-wavelength regions are selected from within the Spitzer

SEDS survey, providing complementary IRAC data down to 26.5 AB mag, a

unique resource for stellar masses at high redshifts. The use of five

widely separated fields mitigates cosmic variance and yields

statistically robust samples of galaxies down to 10^9 M_Sun out to z~8.

We adopt a two-tiered strategy with a "Wide" component (roughly 2 orbits

deep over ~0.2 sq. degrees) and a "Deep" component (roughly 12 orbits

deep over ~0.04 sq. degrees). Combining these with ultra-deep imaging

from the Cycle 17 HUDF09 program yields a three-tiered strategy for

efficient sampling of both rare/bright and faint/common objects.

Three of the Wide-survey fields are located in COSMOS, EGS, and

UKIDSS/UDS. Each of these consists of roughly 3x15 WFC3/IR tiles. Each

WFC3 tile will be observed for 2 orbits, with single orbits separated in

time to allow a search for high-redshift Type Ia SNe. The co-added

exposure times will be approximately 2/3 orbit in J (F125W) and 4/3

orbit in H (F160W). ACS parallels overlap most of the WFC3 area and will

consist of roughly 2/3 orbits in V (F606W) and 4/3 orbit in I (F814W).

Because of the larger area of ACS, this results in effective exposures

that are twice as long (4/3 in V, 8/3 in I), making a very significant

improvement to existing ACS mosaics in COSMOS and EGS and creating a new

ACS mosaic in UDS/UKIDSS where none now exists. Other Wide-survey

components are located in the GOODS fields (North and South) surrounding

the Deep-survey areas.

The Deep-survey fields cover roughly half of each GOODS field, with

exact areas and placements to be determined as part of the Phase-2

process. Each WFC3/IR tile within the Deep regions will receive

approximately 12 orbits of exposure time split between Y (F105W), J

(F125W), and H (F160W). Multi-epoch imaging will provide an efficient

search for high-redshift Type Ia SNe here also. ACS parallels are also

taken in the Deep regions, with the goal of assembling enough total

exposure time in F850LP and other filters to identify high redshift z>6

galaxies in concert with WFC3/IR data using the Lyman break technique.

A portion of the GOODS-N campaign will take place while the field is in

the HST Continuous Viewing Zone (CVZ). The bright time in those orbits

will be used to obtain UV imaging with WFC3 in the F275W and F336W

filters. The exact number of orbits will not be known until Phase-2

planning is complete, but we anticipate that it will be possible to

schedule at least 100 orbits, resulting in 5-sigma point-source depths

of 26.6, 26.4 in F275W and F336W, respectively. The science goals

include measuring the Lyman-continuum escape fractions for galaxies at

z~2.5 and identifying Lyman-break galaxies at z~2-3.

The Type Ia supernova search program in this proposal is integrated with

that in the Postman cluster MCT proposal, with this one stressing the

more distant supernovae. A combined follow-up program will provide light

curves and grism spectra of 15-20 of the best candidates at redshifts

1<z<2. The observing configuration for the follow up will depend on the

redshift of the supernova, and will likely include a grism observation

with either ACS G800L, WFC3-IR G102, or G141, and light curves observed

with F850LP, WFC3-IR F125W, and F160W.

The new data will be used to answer many urgent questions in galaxy

evolution and cosmology. In the reionization era, we will identify

hundreds of high-confidence z>7 galaxies in the Deep regions, in

addition to hundreds of highly-luminous candidates in the Wide regions

for detailed follow-up. These samples will be used to construct a

unified picture of star-formation and stellar mass buildup in early

galaxies. Extremely deep X-ray data will reveal distant AGNs to z>6,

shedding light on the earliest stages of BH growth. In the peak star

formation/QSO era, z~2, we will document the properties of early disks,

the build-up of bulges, the evolution of mergers, and the nature of AGN

hosts to construct an integrated model for structural evolution, star

formation quenching, and AGN triggering. Finally, the ~8 Type Ia SNe

found beyond z>1.5 in the supernova programs will establish the

constancy of these standard candles independent of dark energy and yield

the first measurement of the Type Ia rate at z~2 to distinguish among

different progenitor models. Lower-redshift SNe Ia at 1<z<1.5 will be

used to measure the evolution of dark energy.

This program takes full advantage of MCTP mode to fulfill Hubble's

legacy for deep extragalactic science and prepare the way for JWST.

COS/NUV 12041

COS-GTO: Io Atmosphere/STIS

We will use six HST orbits with COS to observe the disk-integrated

longitudinal distribution of Io's atmosphere, and ten HST orbits with

STIS to provide complementary disk-resolved information at key

locations. We will use the COS G225M grating to observe four SO2

absorption bands, which can be used to determine SO2 atmospheric

density. Disk-integrated 19 micron observations of the atmosphere

indicate that the anti-Jupiter hemisphere of Io has an atmospheric

density roughly ten times greater than the Jupiter-facing side (Spencer

et al. 2005), and mm-wave observations suggest a similar pattern.

However the infrared and mm-wave observations cannot easily separate

atmospheric density from atmospheric temperature, so these results are

model-dependent. Sparse 2100 2300 disk-resolved observations (McGrath et

al. 2000, Jessup et al. 2004) tell a consistent story, but do not cover

enough of Io's surface to provide full confirmation of the

long-wavelength result. We will therefore observe Io's disk-integrated

atmospheric density at six longitudes, roughly 30, 90, 150, 210, 270,

and 330 W, to confirm the 19 micron results and improve our ability to

model the 19-micron data. With STIS, we plan disk-resolved 2000-3200

spectroscopy of Io's SO2 atmosphere. Our observations will target

low-latitude regions away from active plumes (in contrast to our Cycle

10 observations (Jessup et al. 2004) which targeted the Prometheus

plume), to look for the effect of plumes on the atmosphere. We will also

look at the variation of low-latitude atmospheric abundance with terrain

type, to look for explanations for the large longitudinal variations in

atmospheric pressure to be studied with COS. Finally, we will look at a

variety of regions at two different times of day to determine the extent

of diurnal variations in the atmosphere, which are expected if the

atmosphere is dominantly supported by frost sublimation.

ACS/WFC 11996

CCD Daily Monitor (Part 3)

This program comprises basic tests for measuring the read noise and dark

current of the ACS WFC and for tracking the growth of hot pixels. The

recorded frames are used to create bias and dark reference images for

science data reduction and calibration. This program will be executed

four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To

facilitate scheduling, this program is split into three proposals. This

proposal covers 308 orbits (19.25 weeks) from 21 June 2010 to 1 November

2010.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more

reliably removed from science data using darks taken with the same

exposure sequences as the science data, than with a single dark current

image scaled by desired exposure time. Therefore, dark current images

must be collected using all sample sequences that will be used in

science observations. These observations will be used to monitor changes

in the dark current of the WFC3-IR channel on a day-to-day basis, and to

build calibration dark current ramps for each of the sample sequences to

be used by Gos in Cycle 17. For each sample sequence/array size

combination, a median ramp will be created and delivered to the

calibration database system (CDBS).

WFC3/UVIS 11907

UVIS Cycle 17 Contamination Monitor

The UV throughput of WFC3 during Cycle 17 is monitored via weekly

standard star observations in a subset of key filters covering 200-600nm

and F606W, F814W as controls on the red end. The data will provide a

measure of throughput levels as a function of time and wavelength,

allowing for detection of the presence of possible contaminants.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set of

full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K

subarray biases are acquired at less frequent intervals throughout the

cycle to support subarray science observations. The internals from this

proposal, along with those from the anneal procedure (Proposal 11909),

will be used to generate the necessary superbias and superdark reference

files for the calibration pipeline (CDBS).

COS/FUV 11895

FUV Detector Dark Monitor

Monitor the FUV detector dark rate by taking long science exposures

without illuminating the detector. The detector dark rate and spatial

distribution of counts will be compared to pre-launch and SMOV data in

order to verify the nominal operation of the detector. Variations of

count rate as a function of orbital position will be analyzed to find

dependence of dark rate on proximity to the SAA. Dependence of dark rate

as function of time will also be tracked.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate by

taking long science exposures with no light on the detector. The

detector dark rate and spatial distribution of counts will be compared

to pre-launch and SMOV data in order to verify the nominal operation of

the detector. Variations of count rate as a function of orbital position

will be analyzed to find dependence of dark rate on proximity to the

SAA. Dependence of dark rate as function of time will also be tracked.

STIS/CCD 11847

CCD Bias Monitor-Part 2

Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,

and 1x1 at gain = 4, to build up high-S/N superbiases and track the

evolution of hot columns.

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 11721

Verifying the Utility of Type Ia Supernovae as Cosmological Probes:

Evolution and Dispersion in the Ultraviolet Spectra

The study of distant type Ia supernova (SNe Ia) offers the most

practical and immediate discriminator between popular models of dark

energy. Yet fundamental questions remain over possible

redshift-dependent trends in their observed and intrinsic properties.

High-quality Keck spectroscopy of a representative sample of 36

intermediate redshift SNe Ia has revealed a surprising, and unexplained,

diversity in their rest-frame UV fluxes. One possible explanation is

hitherto undiscovered variations in the progenitor metallicity.

Unfortunately, this result cannot be compared to local UV data as only

two representative SNe Ia have been studied near maximum light. Taking

advantage of two new `rolling searches' and the restoration of STIS, we

propose a non-disruptive TOO campaign to create an equivalent comparison

local sample. This will allow us to address possible evolution in the

mean UV spectrum and its diversity, an essential precursor to the study

of SNe beyond z~1.

WFC3/IR 11694

Mapping the Interaction Between High-Redshift Galaxies and the

Intergalactic Environment

With the commissioning of the high-throughput large-area camera WFC3/IR,

it is possible for the first time to undertake an efficient survey of

the rest-frame optical morphologies of galaxies at the peak epoch of

star formation in the universe. We therefore propose deep WFC3/IR

imaging of over 320 spectroscopically confirmed galaxies between

redshift 1.6 < z < 3.4 in well-studied fields which lie along the line

of sight to bright background QSOs. The spectra of these bright QSOs

probe the IGM in the vicinity of each of the foreground galaxies along

the line of sight, providing detailed information on the physical state

of the gas at large galactocentric radii. In combination with our

densely sampled UV/IR spectroscopy, stellar population models, and

kinematic data in these fields, WFC3/IR imaging data will permit us to

construct a comprehensive picture of the structure, dynamics, and star

formation properties of a large population of galaxies in the early

universe and their effect upon their cosmological environment.

S/C 11639

Catching Accreting WDs Moving into Their Instability Strip(s)

Our past HST studies of the temperatures of 9 accreting, pulsating white

dwarfs in cataclysmic variables show that 3 are in the normal

instability strip for single white dwarfs, but the other 6 are much

hotter (15, 000-16, 500K). This dual strip has been proposed to be due

to mass differences in the white dwarfs related to evolutionary history

and driven by the ionization of different elements in their respective

driving regions. In 2007, GW Lib (the brightest and best studied of the

6 hot accreting pulsators) and V455 And (the brightest and best studied

of the 3 cool accreting pulsators) underwent rare large amplitude dwarf

nova outbursts (known to heat the white dwarf) and their pulsations

disappeared. We propose COS observations to: a) take advantage of the

unprecedented opportunity to view the change in pulsation modes due to

cooling of the white dwarf envelope and b) determine the masses of the

white dwarfs to test the dual strip theory. In addition, a nova that had

its outburst 22 yrs ago has begun non-radial pulsations as it returns to

quiescence. We will use COS to determine its temperature in relation to

the instability strip for the pulsating white dwarfs in dwarf novae.

ACS/WFC3 11575

The Stellar Origins of Supernovae

Supernovae (SNe) have a profound effect on galaxies, and have been used

recently as precise cosmological probes, resulting in the discovery of

the accelerating Universe. They are clearly very important events

deserving of intense study. Yet, even with nearly 4000 known SNe, we

know relatively little about the stars which give rise to these powerful

explosions. The main limitation has been the lack of spatial resolution

in pre-SN imaging data. However, since 1999 our team has been at the

vanguard of directly identifying SN progenitor stars in HST images. From

this exciting new line of study, the emerging trend from 5 detections

for Type II- Plateau SNe is that their progenitors appear to be

relatively low mass (8 to 20 Msun) red supergiants, although more cases

are needed. Nonetheless, the nature of the progenitors of Type Ib/c SNe,

a subset of which are associated with the amazing gamma-ray bursts,

remains ambiguous. Furthermore, we remain in the continually

embarrassing situation that we still do not yet know which progenitor

systems explode as Type Ia SNe, which are currently being used for

precision cosmology. In Cycle 16 we have triggered on the Type Ic SN

2007gr and Type IIb SN 2008ax so far. We propose to determine the

identities of the progenitors of 4 SNe within 17 Mpc, which we expect to

occur during Cycle 17, through ToO observations using ACS/HRC.

COS/NUV/FUV 11532

COS-GTO: Activity of Solar Mass Stars from Cradle to Grave

COS spectra will be very useful for answering the question of how

chromospheric and coronal activity of stars decline as stars lose

angular momentum and magnetic fields with age. This question is

important for modeling the atmospheres of young planets that are blasted

by strong ultraviolet radiation and winds from young stars. COS will

obtain spectra of solar mass stars with a range of ages from 10 Myr to 7

Gyr.