HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4637

PERIOD COVERED: 5am June 20 - 5am June 23, 2008 (DOY 172/0900z-175/0900z)

OBSERVATIONS SCHEDULED

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.

WFPC2 11235

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies

in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared

selected galaxies exceeds that of optically selected galaxies. These

`luminous infrared galaxies' {LIRGs} are primarily interacting or

merging disk galaxies undergoing enhanced star formation and Active

Galactic Nuclei {AGN} activity, possibly triggered as the objects

transform into massive S0 and elliptical merger remnants. We propose

NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88

L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised

Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}.

This sample is ideal not only in its completeness and sample size, but

also in the proximity and brightness of the galaxies. The superb

sensitivity and resolution of NICMOS NIC2 on HST enables a unique

opportunity to study the detailed structure of the nuclear regions,

where dust obscuration may mask star clusters, AGN and additional nuclei

from optical view, with a resolution significantly higher than possible

with Spitzer IRAC. This survey thus provides a crucial component to our

study of the dynamics and evolution of IR galaxies presently underway

with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88

galaxies. Imaging will be done with the F160W filter {H-band} to examine

as a function of both luminosity and merger stage {i} the luminosity and

distribution of embedded star clusters, {ii} the presence of optically

obscured AGN and nuclei, {iii} the correlation between the distribution

of 1.6 micron emission and the mid- IR emission as detected by Spitzer

IRAC, {iv} the evidence of bars or bridges that may funnel fuel into the

nuclear region, and {v} the ages of star clusters for which photometry

is available via ACS/WFC observations. The NICMOS data, combined with

the HST ACS, Spitzer, and GALEX observations of this sample, will result

in the most comprehensive study of merging and interacting galaxies to

date.

WFPC2 11233

Multiple Generations of Stars in Massive Galactic Globular Clusters

This is a follow-up to recent HST imaging of NGC 2808, which discovered

that its main sequence is triple, with three well-separated parallel

branches {Fig.~1}. Along with the double MS of Omega Centauri, this

challenges the long-held paradigm that globular clusters are simple,

single stellar populations. The cause of this main sequence multiplicity

in both clusters is likely to be differences in helium abundance, which

could play a fundamental role in the understanding of stellar

populations. We propose to image seven more of the most massive globular

clusters, to examine their main sequences for indications of splitting.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That

measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a

useful result, judged by the over ten refereed citations each year

since. It is, however, unsatisfactory to have the direct,

parallax-based, distance scale of Population II variables based on a

single star. We propose, therefore, to obtain the parallaxes of four

additional RR Lyrae stars and two Population II Cepheids, or W Vir

stars. The Population II Cepheids lie with the RR Lyrae stars on a

common K-band Period-Luminosity relation. Using these parallaxes to

inform that relationship, we anticipate a zero-point error of 0.04

magnitude. This result should greatly strengthen confidence in the

Population II distance scale and increase our understanding of RR Lyrae

star and Pop II Cepheid astrophysics.

WFPC2 11206

At the Cradle of the Milky Way: Formation of the Most Massive Field Disk

Galaxies at z>1

We propose to obtain 2 orbit WFPC2 F814W images of a sample of the 15

most massive galaxies found at $1 < z < 1.3$. These were culled from

over 20,000 Keck spectra collected as part of DEEP and are unique among

high redshift massive galaxy samples in being kinematically selected.

Through a recent HST NICMOS-2 imaging program {GO-10532}, we have

confirmed that these galaxies have regular stellar disks, and their

emission line kinematics are not due to gradients from merging

components. These potentially very young galaxies are likely precursors

to massive local disks, assuming no further merging. The proposed WFPC2

and existing NIC-2 data provide colors, stellar masses, and ages of

bulge and disk subcomponents, to assess whether old stellar bulges and

disks are in place at that time or still being built, and constrain

their formation epochs. Finally, this sample will yield the first

statistically significant results on the $z > 1$ evolution of the

size-velocity-luminosity scaling relations, for massive galaxies at

different wavelengths, and constrain whether this evolution reflects

stellar mass growth, or passive evolution, of either bulge or disk

components.

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!

WEPC2 11196

An Ultraviolet Survey of Luminous Infrared Galaxies in the Local

Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared

selected galaxies exceeds that of optically selected galaxies. These

Luminous Infrared Galaxies {LIRGs} are primarily interacting or merging

disk galaxies undergoing starbursts and creating/fueling central AGN. We

propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W} UV imaging of a

sample of 27 galaxies drawn from the complete IRAS Revised Bright Galaxy

Sample {RBGS} LIRGs sample and known, from our Cycle 14 B and I-band ACS

imaging observations, to have significant numbers of bright {23 < B < 21

mag} star clusters in the central 30 arcsec. The HST UV data will be

combined with previously obtained HST, Spitzer, and GALEX images to {i}

calculate the ages of the clusters as function of merger stage, {ii}

measure the amount of UV light in massive star clusters relative to

diffuse regions of star formation, {iii} assess the feasibility of using

the UV slope to predict the far-IR luminosity {and thus the star

formation rate} both among and within IR-luminous galaxies, and {iv}

provide a much needed catalog of rest- frame UV morphologies for

comparison with rest-frame UV images of high-z LIRGs and Lyman Break

Galaxies. These observations will achieve the resolution required to

perform both detailed photometry of compact structures and spatial

correlations between UV and redder wavelengths for a physical

interpretation our IRX-Beta results. The HST UV data, combined with the

HST ACS, Spitzer, Chandra, and GALEX observations of this sample, will

result in the most comprehensive study of luminous starburst galaxies to

date.

NIC3 11147

The Origin of Diffuse UV Light from Spiral Disks

The ultraviolet light from galaxies has been used as a beacon for

tracing the cosmic star formation history of the Universe, yet we have

an incomplete understanding of many characteristics of this light. Most

of the UV emission from nearby, normal star--forming galaxies is

unresolved and "diffuse", and GALEX has shown that in spiral disks it

permeates the inter-arm regions. The nature of this diffuse inter- arm

component is under debate. Recent results suggest that it may arise from

non- ionizing UV photons which originate in star forming regions in the

spiral arms, travel in the plane of the galaxy, and then scatter off of

diffusely distributed cold dust grains. Alternatively, an in-situ,

unresolved stellar population could produce the observed inter-arm UV

emission. This project seeks to establish which of the two competing

scenarios is responsible for the bulk of this diffuse emission. We

propose to use HST's UV imaging capability (ACS/SBC) to obtain deep

observations of selected fields in the nearby spiral galaxy M101, for

which available (low angular resolution) data favor the 'scattered

light' scenario. Our observations are designed to detect any faint,

UV-luminous stellar population down to main sequence B5 stars. With

these data, we will establish the nature of the bulk of the diffuse UV

light in this spiral galaxy by: (i) quantifying the contribution from

dust-scattered light; (ii) measuring the contribution to the ubiquitous

diffuse ionized medium from in- situ ionizing stars; and (iii) providing

constraints on the observed stellar mass function in the field. Only HST

has the UV sensitivity and angular resolution to discriminate in-situ

stellar populations from scattered light. The ultimate goal of this

project is to re-'calibrate' the UV emission as a star formation rate

indicator, which will need to account for any scattered component.

NIC2 11143

NICMOS Imaging of Submillimeter Galaxies With CO and PAH Redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter

galaxies {SMGs} whose optical redshifts have been confirmed by the

detection of millimeter CO and/or mid- infrared PAH emission. With the

4000A break falling within/between the two imaging filters, we will be

able to study these sources' spatially resolved stellar populations

{modulo extinction} in the rest-frame optical. SMGs' large luminosities

appear to be due largely to merger-triggered starbursts; high-resolution

NICMOS imaging will help us understand the stellar masses, mass ratios,

and other properties of the merger progenitors, valuable information in

the effort to model the mass assembly history of the universe.

WFPC2 11137

First Accurate Geometric Distance to a Galactic Wolf-Rayet Star: Knots

in the Ejecta M1-67

M 1-67 is the youngest known ejection nebula surrounding a Population I

Wolf-Rayet star, in this case the WN8 star WR 124. Our deep H-alpha

HST/WFPC2 image of this object in March 1997 revealed, for the first

time in such a nebula, numerous bright, mostly unresolved knots (typical

diameters 0.1-0.2") often surrounded by what appear to be their own

local spherical diffuse 'wind' bubbles. We propose to obtain a second

epoch H-alpha image of M 1-67, essentially repeating the Epoch1

instrumental set-up. By measuring the proper motions of the knots, we

will derive a relatively precise and assumption-free geometric distance

(thus also a luminosity) to a Galactic Wolf-Rayet star, the first of its

kind. This will help to confirm the suspected runaway status of WR 124

and shed new light on the nature of progenitors of gamma-ray bursts.

Moreover, we intend to document and measure the anticipated

morphology/brightness changes in the fine-stucture features of the

nebula over the 11-year interval, as they relate to wind-embedded

shocks. This will provide important input for interaction models of a

stellar wind with circumstellar matter.

ACS/SBC 11110

Searching for Lyman Apha Emission from FUSE Lyman Continuum Candidates

We have recently been granted time on FUSE to characterize the escape

fraction of hydrogen Lyman continuum (Lyc) photons from a

morphologically diverse set of star forming galaxies. The FUSE program

is designed to provide ~ 5 sigma detections of Lyc photons emitted from

star forming galaxies with escape fractions ~5%. With this proposal we

seek hydrogen Lyman alpha (Lya) observations of a representative subset

of the FUSE program targets to constrain the observational relationship

between Lyc, Lya, and hydrogen Balmer line emission in these systems.

Such observations explore the detailed balance between the simple

optically thin (Case A) and optically thick (Case B) limits in

recombination theory. The ultimate goal of this program is to quantify

the relationship between escaping Lya and Lyc emission and the first

structures that form in the early universe.

WFPC2 11079

Treasury Imaging of Star Forming Regions in the Local Group:

Complementing the GALEX and NOAO Surveys

We propose to use WFPC2 to image the most interesting star-forming

regions in the Local Group galaxies, to resolve their young stellar

populations. We will use a set of filters including F170W, which is

critical to detect and characterize the most massive stars, to whose hot

temperatures colors at longer wavelengths are not sensitive. WFPC2's

field of view ideally matches the typical size of the star-forming

regions, and its spatial resolution allows us to measure individual

stars, given the proximity of these galaxies. The resulting H-R diagrams

will enable studies of star-formation properties in these regions, which

cover largely differing metallicities {a factor of 17, compared to the

factor of 4 explored so far} and characteristics. The results will

further our understanding of the star-formation process, of the

interplay between massive stars and environment, the properties of dust,

and will provide the key to interpret integrated measurements of

star-formation indicators {UV, IR, Halpha} available for several

hundreds more distant galaxies. Our recent deep surveys of these

galaxies with GALEX {FUV, NUV} and ground-based imaging {UBVRI, Halpha,

[OIII] and [SII]} provided the identification of the most relevant SF

sites. In addition to our scientific analysis, we will provide catalogs

of HST photometry in 6 bands, matched corollary ground-based data, and

UV, Halpha and IR integrated measurements of the associations, for

comparison of integrated star-formation indices to the resolved

populations. We envisage an EPO component.

WFPC2 11032

CTE Extended Targets Closeout

Measuring the charge transfer efficiency {CTE} of an astronomical CCD

camera is crucial to determining the CCD's photometric fidelity across

the field of view. WFPC2's CTE has degraded steadily over the last 13

years because of continuous exposure to trapped particles in HST's

radiation environment. The fraction of photometric signal lost from

WFPC2's CTI {change transfer inefficiency} is a function of WFPC2's time

in orbit, the integrated signal in the image, the location of the image

on the CCD, and the background signal. Routine monitoring of WFPC2's

degrading CTE over the last 13 years has primarily concerned the effects

of CTI on point-source photometry. However, most of the sources imaged

by WFPC2 are extended rather than point- like. This program aims to

characterize the effects of CTI on the photometry and morphology of

extended sources near the end of WFPC2's functional life. Images of a

standard field within the rich galaxy cluster Abell 1689 are recorded

with each WFPC2 camera using the F606W and F814W filters. These images

will be compared with contemporaneous images of Abell 1689 recorded with

the field rotated by approximately 180 degrees to assess differences

between extended sources imaged near and far from the serial register.

The images will also be compared with similar images recorded in Cycle 8

{Program 8456} to characterize the rate of CTE degradation over the

lifetime of WFPC2.

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.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

11350 - REacq(1,2,1) failed to RGA hold.

           REacq(1,2,1) scheduled at 172/17:16:56 - 17:24:18 failed to RGA hold

           during LOS. At AOS there were no flags. During LOS we received an ESB

           a0a "FL Timeout". OBAD1 showed errors of V1=435.74, V2=633.13,

           V3=-307.65, and RSS=827.87. OBAD2 showed errors of V1=-0.75, V2=-2.32,

           V3=11.46, and RSS=11.71.

           Observations affected: WFPC 152-155 Proposal ID# 11233

           The REacq(1,2,1) scheduled at 172/18:52:49 - 19:00:00 also failed during

           LOS. There were no flags. OBAD1:V1=-365.74, V2=-546.47,V3=148.45,

           RSS=674.11 OBAD2: V1=0.25, V2=0.89, V3=2.09, RSS=2.28

           Observations affected: WFPC 156-159 Proposal ID# 11233

           Reacq(1,2,1) scheduled at 172/20:28:42 also failed to RGA hold. ESB

           message a0a "FL Timeout" was received.

           OBAD1: V1=-435.55, V2=-648.68, V3=189.11, RSS=803.90

           OBAD2: V1=1.45, V2=4.26, V3=8.64, RSS=9.73

           Observations affected: WFPC 160-162 Proposal ID#11233

           Upon acquisition of signal at 172/22:39:30, the REacq(1,2,1) scheduled

           at 172/22:09:38 had failed to RGA Hold with (QF1SRLEX), (QF1STOPF)

           indication flags set on FGS-1. One 486 ESB message "a07" (FGS Coarse

           Track failed - Timed out waiting for data valid FGS-1) was received.

           Pre-acq OBADs attitude corrections (RSS) values are not available due to

           LOS. Post-acq OBAD/MAP had not been scheduled.

           Observations affected: WFPC 164, 165 Proposal ID#11233

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                      SCHEDULED      SUCCESSFUL 

FGS GSacq               17                 17                           

FGS REacq               10                 06      

OBAD with Maneuver 54                 54              

SIGNIFICANT EVENTS: (None)