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      # 4458

PERIOD COVERED: UT September 271,272,273, 2007 (DOY 28,29,30)

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 11312

The Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing

Observations with WFPC2

LoCuSS is a systematic and detailed investigation of the mass,

substructure, and thermodynamics of 100 X-ray luminous galaxy clusters

at 0.15<z<0.3. The primary goal is to test our recent suggestion that

this population is dominated by dynamically immature disturbed clusters,

and that the observed mass-temperature relation suffers strong

structural segregation. If confirmed, this would represent a paradigm

shift in our observational understanding of clusters, that were hitherto

believed to be dominated by mature, undisturbed systems. We propose to

complete our successful Cycle 15 program {SNAP:10881} which prior to

premature termination had delivered robust weak-lensing detections in 17

clusters, and candidate strongly-lensed arcs in 11 of these 17. These

strong and weak lensing signals will give an accurate measure of the

total mass and structure of the dark matter distribution that we will

subsequently compare with X-ray and Sunyaev Zeldovich Effect

observables. The broader applications of our project include 1} the

calibration of mass-temperature and mass-SZE scaling relations which

will be critical for the calibration of proposed dark energy

experiments, and 2} the low redshift baseline study of the demographics

of massive clusters to aid interpretation of future high redshift {z>1}

cluster samples. To complete the all-important high resolution imaging

component of our survey, we request deep WFPC2 observations of 20

clusters through the F606W filter, for which wide-field weak-lensing

data are already available from our Subaru imaging program. The

combination of deep WFPC2 and Subaru data for these 20 clusters will

enable us to achieve the science program approved by the Cycle 15 TAC.

WFPC2 11292

The Ring Plane Crossings of Uranus in 2007

The rings of Uranus turn edge-on to Earth in May and August 2007. In

between, we will have a rare opportunity to see the unlit face of the

rings. With the nine optically thick rings essentially invisible, we

will observe features and phenomena that are normally lost in their

glare. We will use this opportunity to search thoroughly for the

embedded "shepherd" moons long believed to confine the edges of the

rings, setting a mass limit roughly 10 times smaller than that of the

smallest shepherd currently known, Cordelia. We will measure the

vertical thicknesses of the rings and study the faint dust belts only

known to exist from a single Voyager image. We will also study the

colors of the newly-discovered faint, outer rings; recent evidence

suggests that one ring is red and the other blue, implying that each

ring is dominated by a different set of physical processes. We will

employ near- edge-on photometry from 2006 and 2007 to derive the

particle filling factor within the rings, to observe how ring epsilon

responds to the "traffic jam" as particles pass through its narrowest

point, and to test the latest models for preserving eccentricities and

apse alignment within the rings. Moreover, this data set will allow us

to continue monitoring the motions of the inner moons, which have been

found to show possibly chaotic orbital variations; by nearly doubling

the time span of the existing Hubble astrometry, the details of the

variations will become much clearer.

NIC2 11219

Active Galactic Nuclei in nearby galaxies: a new view of the origin of

the radio-loud radio- quiet dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type

galaxies {drawn from a complete radio selected sample} we have found

evidence that the radio-loud/radio-quiet dichotomy is directly connected

to the structure of the inner regions of their host galaxies in the

following sense: [1] Radio-loud AGN are associated with galaxies with

shallow cores in their light profiles [2] Radio-quiet AGN are only

hosted by galaxies with steep cusps. Since the brightness profile is

determined by the galaxy's evolution, through its merger history, our

results suggest that the same process sets the AGN flavour. This

provides us with a novel tool to explore the co-evolution of galaxies

and supermassive black holes, and it opens a new path to understand the

origin of the radio-loud/radio-quiet AGN dichotomy. Currently our

analysis is statistically incomplete as the brightness profile is not

available for 82 of the 116 targets. Most galaxies were not observed

with HST, while in some cases the study is obstructed by the presence of

dust features. We here propose to perform an infrared NICMOS snapshot

survey of these 82 galaxies. This will enable us to i} test the reality

of the dichotomic behaviour in a substantially larger sample; ii} extend

the comparison between radio-loud and radio-quiet AGN to a larger range

of luminosities.

WFPC2 11218

Snapshot Survey for Planetary Nebulae in Globular Clusters of the Local

Group

Planetary nebulae {PNe} in globular clusters {GCs} raise a number of

interesting issues related to stellar and galactic evolution. The number

of PNe known in Milky Way GCs, 4, is surprisingly low if one assumes

that all stars pass through a PN stage. However, it is likely that the

remnants of stars now evolving in Galactic GCs leave the AGB so slowly

that any ejected nebula dissipates long before the star becomes hot

enough to ionize it. Thus there should not be ANY PNe in Milky Way

GCs--but there are four! It has been suggested that these PNe are the

result of mergers of binary stars within GCs, i.e., that they are

descendants of blue stragglers. The frequency of occurrence of PNe in

external galaxies poses more questions, because it shows a range of

almost an order of magnitude. I propose a Snapshot survey aimed at

discovering PNe in the GC systems of Local Group galaxies more distant

than the Magellanic Clouds. These clusters, some of which may be much

younger than their counterparts in the Milky Way, might contain many

more PNe than those of our own galaxy. I will use the standard technique

of emission-line and continuum imaging, which easily discloses PNe.

NIC3 11107

Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy

Formation in the Early Universe

We have used the ultraviolet all-sky imaging survey currently being

conducted by the Galaxy Evolution Explorer {GALEX} to identify for the

first time a rare population of low- redshift starbursts with properties

remarkably similar to high-redshift Lyman Break Galaxies {LBGs}. These

"compact UV luminous galaxies" {UVLGs} resemble LBGs in terms of size,

SFR, surface brightness, mass, metallicity, kinematics, dust, and color.

The UVLG sample offers the unique opportunity of investigating some very

important properties of LBGs that have remained virtually inaccessible

at high redshift: their morphology and the mechanism that drives their

star formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS

in order to 1} characterize their morphology and look for signs of

interactions and mergers, and 2} probe their star formation histories

over a variety of timescales. The images show a striking trend of

small-scale mergers turning large amounts of gas into vigorous

starbursts {a process referred to as dissipational or "wet" merging}.

Here, we propose to complete our sample of 31 LBG analogs using the

ACS/SBC F150LP {FUV} and WFPC2 F606W {R} filters in order to create a

statistical sample to study the mechanism that triggers star formation

in UVLGs and its implications for the nature of LBGs. Specifically, we

will 1} study the trend between galaxy merging and SFR in UVLGs, 2}

artificially redshift the FUV images to z=1-4 and compare morphologies

with those in similarly sized samples of LBGs at the same rest-frame

wavelengths in e.g. GOODS, UDF, and COSMOS, 3} determine the presence

and morphology of significant stellar mass in "pre-burst" stars, and 4}

study their immediate environment. Together with our Spitzer

{IRAC+MIPS}, GALEX, SDSS and radio data, the HST observations will form

a unique union of data that may for the first time shed light on how the

earliest major episodes of star formation in high redshift galaxies came

about. This proposal was adapted from an ACS HRC+WFC proposal to meet

the new Cycle 16 observing constraints, and can be carried out using the

ACS/SBC and WFPC2 without compromising our original science goals.

NIC2 11101

The Relevance of Mergers for Fueling AGNs: Answers from QSO Host

Galaxies

The majority of QSOs are known to reside in centers of galaxies that

look like ellipticals. Numerical simulations have shown that remnants of

galaxy mergers often closely resemble elliptical galaxies. However, it

is still strongly debated whether the majority of QSO host galaxies are

indeed the result of relatively recent mergers or whether they are

completely analogous to inactive ellipticals to which nothing

interesting has happened recently. To address this question, we recently

obtained deep HST ACS images for five QSO host galaxies that were

classified morphologically as ellipticals {GO-10421}. This pilot study

revealed striking signs of tidal interactions such as ripples, tidal

tails, and warped disks that were not detected in previous studies. Our

observations show that at least some "elliptical" QSO host galaxies are

the products of relatively recent merger events rather than old galaxies

formed at high redshift. However, the question remains whether the host

galaxies of classical QSOs are truly distinct from inactive ellipticals

and whether there is a connection between the merger events we detect

and the current nuclear activity. We must therefore place our results

into a larger statistical context. We are currently conducting an HST

archival study of inactive elliptical galaxies {AR-10941} to form a

control sample. We now propose to obtain deep HST/WFPC2 images of 13

QSOs whose host galaxies are classified as normal ellipticals. Comparing

the results for both samples will help us determine whether classical

QSOs reside in normal elliptical galaxies or not. Our recent pilot study

of five QSOs indicates that we can expect exciting results and deep

insights into the host galaxy morphology also for this larger sample of

QSOs. A statistically meaningful sample will help us determine the true

fraction of QSO hosts that suffered strong tidal interactions and thus,

whether a merger is indeed a requirement to trigger nuclear activity in

the most luminous AGNs. In addition to our primary science observations

with WFPC2, we will obtain NICMOS3 parallel observations with the

overall goal to select and characterize galaxy populations at high

redshifts. The imaging will be among the deepest NICMOS images: These

NICMOS images are expected to go to a limit a little over 1 magnitude

brighter than HUDF-NICMOS data, but over 13 widely separated fields,

with a total area about 1.5 times larger than HUDF-NICMOS. This

separation means that the survey will tend to average out effects of

cosmic variance. The NICMOS3 images will have sufficient resolution for

an initial characterization of galaxy morphologies, which is currently

one of the most active and promising areas in approaching the problem of

the formation of the first massive galaxies. The depth and area coverage

of our proposed NICMOS observations will also allow a careful study of

the mass function of galaxies at these redshifts. This provides a large

and unbiased sample, selected in terms of stellar mass and unaffected by

cosmic variance, to study the on-going star formation activity as a

function of mass {i.e. integrated star formation} at this very important

epoch.

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 11033

Full Moon Earth Flats Closeout

Flat field exposures will be obtained by observing the moonlit Earth

with the broadband WFPC2 filters F606W and F814W, which saturate in the

minimum exposure time on the sunlit Earth. These observations will be

used to improve the flats currently in the pipeline and are part of the

WFPC2 closeout operations. Because CTE effects are large for star flats

and small for full field illumination, Earth flats are the superior

technique.

FGS 10930

Mass and Radius of a Near-Chandrasekhar-limit magnetic white dwarf

REJ0317-853 is a unique object. According to our analyses it is the most

massive white dwarf ever found, with a mass of 1.35 solar masses,

approaching the Chandrasekhar limit. With a period of just 725 seconds

it is the most rapidly rotating isolated white dwarf ever found.

Moreover, RE J0317-853 is the hottest magnetic white dwarf discovered so

far and has a strong magnetic field varying from about 180 to more than

700 MG over the stellar surface. Due to its strong polarization and high

mass it has been used to test gravitational theories predicting

gravitational birefringence. However, the existing mass and radius

determination is indirect and still uncertain and would greatly profit

from a high-precision parallax determination with the HST FGS.

NIC3 10909

Exploring the diversity of cosmic explosions: The supernovae of

gamma-ray bursts

While the connection between gamma-ray bursts {GRBs} and supernovae

{SNe} is now clearly established, there is a large variety of

observational properties among these SNe and the physical parameters of

these explosions are poorly known. As part of a comprehensive program,

we propose to use HST in order to obtain basic information about the

supernovae associated with gamma-ray bursts. HST offers the means to

cleanly separate the light curves of the GRB afterglow from the

supernova, and to remove the contamination from the host galaxy, opening

a clear route to the fundamental parameters of the SN. From these

observations, we will determine the absolute magnitude at maximum, the

shape of the spectral energy distribution, and any change over time of

the energy distribution. We will also measure the rate of decay of the

exponential tail. Merged with the ground-based data that we will obtain

for each event, we will be able to compare our data set to models and

constrain the energy of the explosion, the mass of the ejecta and the

mass of Nickel synthesized during the explosion. These results will shed

light on the apparent variety of supernovae associated with gamma-ray

bursts and X-ray flashes, and on the relation between these SNe and

other, more common varieties of core-collapse explosions.

ACS/SBC 10872

Lyman Continuum Emission in Galaxies at z=1.2

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

escape fractions of a few percent, up to 10%, with very few detections

{as opposed to upper limits} having been reported. No detections have

been reported in the epochs between z=0.1 and z=2. We propose to measure

the fraction of escaping Lyman continuum radiation from 15 luminous

z~1.2 galaxies in the GOODS fields. Using the tremendous sensitivity of

the ACS Solar- blind Channel, we will reach AB=30 mag., allowing us to

detect an escape fraction of 1%. We will correlate the amount of

escaping radiation with the photometric and morphological properties of

the galaxies. A non-detection in all sources would imply that QSOs

provide the overwhelming majority of ionizing radiation at z=1.3, and it

would strongly indicate that the properties of galaxies at higher

redshift have to be significantly different for galaxies to dominate

reionization. The deep FUV images will also be useful for extending the

FUV study of other galaxies in the GOODS fields.

WFPC2 10787

Modes of Star Formation and Nuclear Activity in an Early Universe

Laboratory

Nearby compact galaxy groups are uniquely suited to exploring the

mechanisms of star formation amid repeated and ongoing gravitational

encounters, conditions similar to those of the high redshift universe.

These dense groups host a variety of modes of star formation, and they

enable fresh insights into the role of gas in galaxy evolution. With

Spitzer mid-IR observations in hand, we have begun to obtain high

quality, multi-wavelength data for a well- defined sample of 12 nearby

{<4500km/s} compact groups covering the full range of evolutionary

stages. Here we propose to obtain sensitive BVI images with the ACS/WFC,

deep enough to reach the turnover of the globular cluster luminosity

function, and WFPC2 U-band and ACS H-alpha images of Spitzer-identified

regions hosting the most recent star formation. In total, we expect to

detect over 1000 young star clusters forming inside and outside

galaxies, more than 4000 old globular clusters in >40 giant galaxies

{including 16 early-type galaxies}, over 20 tidal features,

approximately 15 AGNs, and intragroup gas in most of the 12 groups.

Combining the proposed ACS images with Chandra observations, UV GALEX

observations, ground-based H-alpha imaging, and HI data, we will conduct

a detailed study of stellar nurseries, dust, gas kinematics, and AGN.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

11005 - FHST OBAD Failure

           GSACQ(1,3,3) at 269/04:44:27 acquired in fine lock backup on FGS 1 only,

           with QF3STOPF and QSTOP flags set on FGS 3 at 04:50:02. No other flags

           were seen.

           REACQ(1,3,3) at 06:17:50 also acquired on FGS 1 only.

11008 - GSAcq (1,2,1) failed to RGA Hold (Gyro Control) @ 272/1319z

           At AOS 272/13:19:35 observed that GSAcq (1,2,1) scheduled from

           272/12:32:14-12:39:44 had failed to RGA Hold (Gyro Control). This was

           due to QSTOP flag on FGS 1.

           OBAD #1 V1 93.63, V2 845.44, V3 557.62 RSS 1017.09

           OBAD #2 V1 -2.31, V2 -10.12, V3 6.90, RSS 12.46

           OBAD MAP: V1 -553.72, V2 -828.30, V3 342.81, RSS 1053.66

           REAcq (1,2,1) scheduled from 272/14:06:47-14:14:17 failed to RGA Hold

           (Gyro Control) due to QSTOP flag on FGS 1. There were no OBAD's

           scheduled prior to the re-acquisition.

           OBAD MAP: V1 350.57, V2 583.31, V3 -38.95, RSS 681.67

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL

FGS GSacq                21                  20          

FGS REacq                19                  18             

OBAD with Maneuver  76                  75          

SIGNIFICANT EVENTS: (None)