HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4746

PERIOD COVERED: 5am November 26 - 5am December 1, 2008 (DOY

                          331/1000z-336/1000z)

OBSERVATIONS SCHEDULED

WFPC2/ACS/SBC 11957

Hubble Investigation of Asteroid 21 Lutetia in Support of the Rosetta

Mission Flyby

The Rosetta mission is gearing up for a flyby encounter with the large,

main belt asteroid 21 Lutetia, with closest approach on 2010 June 10.

The next opposition, on 2008 December 1, is our last opportunity to make

observations in time to affect the planning of the Rosetta program. We

request a total of 5 orbits of Hubble observing time (2 using ACS/SBC

and 3 using WFPC2) to characterize the UV albedo of Lutetia, to search

for any dust debris near the main body, and to perform a deep search for

companions. Even one orbit of Hubble time would provide valuable data

for planning the Rosetta-Alice ultraviolet spectrometer observations,

and 2 orbits are sufficient to characterize the far-UV albedo, but a

5-orbit program provides a richer scientific investigation with

potentially much broader implications, both scientifically and for

Rosetta planning.

WFPC2 11956

Hubble Heritage: Side B

We propose a program of 39 orbits to observe 6 targets with WFPC2

following a successful return to science using side B electronics. These

observations will be used for Hubble Heritage releases in the months

leading up to servicing mission 4. Because of launch delays, our reserve

of releasable images is growing dangerously slim. We are proposing here

to replenish one of our important lines of communication with the

public.

We have carefully chosen targets that can efficiently use single

pointings of WFPC2 to obtain images of visually striking and

astrophysically interesting targets. Observations will reach high S/N

and will be dithered and subsampled to improve the resolution and pixel

scale to near ACS/WFC3 quality at a modest cost in exposure time. Most

of the observations will schedule in the interim between a return to

science and the availability of new science proposals that may be

selected in response to an interim call for proposals.

FGS 11943

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries

among some of the most massive, least massive, and oldest stars in our

part of the Galaxy. FGS allows us to spatially resolve binary systems

that are too faint for ground-based, speckle or optical long baseline

interferometry, and too close to resolve with AO. We propose a

SNAP-style program of single orbit FGS TRANS mode observations of very

massive stars in the cluster NGC 3603, luminous blue variables, nearby

low mass main sequence stars, cool subdwarf stars, and white dwarfs.

These observations will help us to (1) identify systems suitable for

followup studies for mass determination, (2) study the role of binaries

in stellar birth and in advanced evolutionary states, (3) explore the

fundamental properties of stars near the main sequence-brown dwarf

boundary, (4) understand the role of binaries for X-ray bright systems,

(5) find binaries among ancient and nearby subdwarf stars, and (6) help

calibrate the white dwarf mass - radius relation.

WFPC2 11796

WFPC2 Cycle 16 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.

FGS 11789

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.

ACS/SBC 11681

A Search for Ultraviolet Emission Filaments in Cool Core Clusters

We propose to use ACS SBC imaging to seek ultraviolet CIV emission

filaments in clusters of galaxies exhibiting strong cool-core X-ray

emission and optical line emission filaments. These short observations

are crafted to test thermal conduction models for the filament

excitation, and can significantly impact our understanding of the

overall physical processes dominant in the galaxy cluster ISM.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

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

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

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

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

be described by isothermal elliptical potentials. In contrast, modeling

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

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

significantly affected by baryon cooling. Until recently, lensing

surveys were neither deep nor extended enough to probe the intermediate

mass density regime, which is fundamental for understanding the assembly

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

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

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

using the most recent CFHTLS data release via automated procedures.

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

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

candidates. These are intermediate mass range candidates {between

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

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

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

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

largest unbiased sample available to date.

ACS/SBC/WFPC2 11230

HST FUV Observations of Brightest Cluster Galaxies: The Role of Star

Formation in Cooling Flows and BCG Evolution

The intracluster medium (ICM) now appears to be a very dynamic place

where heating and cooling processes vie for dominance and an uneasy

equilibrium is maintained. Since these same processes may operate during

the process of galaxy formation, the centers of clusters of galaxies

provide low redshift laboratories for studying the critical processes

involved in galaxy formation and black hole growth. At the present time,

the main questions are (1) How much gas is cooling out of the ICM? (2)

How much star formation is ongoing? (3) What is the impact of the gas

and star formation on the central BCG? In order to measure the current

star formation in BCGs we have undertaken a program of Spitzer IRAC and

MIPS observations. We are in process of obtaining observations of a

sample of Brightest Cluster Galaxies in 70 clusters selected from the

ROSAT all sky survey. In about 25% of the sources observed so far, we

detect a mid-IR excess which we attribute to dust heated by star

formation. We propose to obtain ACS/SBC observations of the Lyman Alpha

emission line and the adjacent FUV continuum in 7 BCGs which are in

cooling core clusters of galaxies and have a large mid-IR excess. We

also propose WFPC2 F606W observations of the two clusters without high

resolution imaging to allow us to image the dust on the same scale as

the Far UV continuum. The FUV will allow us to confirm the presence of

ongoing star formation in these BCGs and will allow us to rule out an

AGN as the dominant contributor to the mid-IR. The morphology and

spatial extent of the young stars and the heated dust and CO will

constrain the spatial scale over which star formation occurs and thus

where the cooling gas is deposited. The combination of our FUV and IR

observations will allow us to estimate the star formation rates which

must balance the rate at which cold gas is deposited in the BCG. Our

proposed FUV observations will produce unique information about the

cooling gas, the true mass accretion rates, and the star formation rates

in BCGs and its effect on the galaxy.

WFPC2 11201

Systemic and Internal Motions of the Magellanic Clouds: Third Epoch

Images

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in

the Magellanic Clouds centered on background quasars. We used these data

to determine the proper motions of the LMC and SMC to better than 5% and

15% respectively. These are by far the best determinations of the proper

motions of these two galaxies. The results have a number of unexpected

implications for the Milky Way-LMC-SMC system. The implied

three-dimensional velocities are larger than previously believed, and

are not much less than the escape velocity in a standard 10^12 solar

mass Milky Way dark halo. Orbit calculations suggest the Clouds may not

be bound to the Milky Way or may just be on their first passage, both of

which would be unexpected in view of traditional interpretations of the

Magellanic Stream. Alternatively, the Milky Way dark halo may be a

factor of two more massive than previously believed, which would be

surprising in view of other observational constraints. Also, the

relative velocity between the LMC and SMC is larger than expected,

leaving open the possibility that the Clouds may not be bound to each

other. To further verify and refine our results we now request an epoch

of WFPC2/PC data for the fields centered on 40 quasars that have at

least one epoch of ACS imaging. We request execution in snapshot mode,

as in our previous programs, to ensure the most efficient use of HST

resources. A third epoch of data of these fields will provide crucial

information to verify that there are no residual systematic effects in

our previous measurements. More importantly, it will increase the time

baseline from 2 to 5 yrs and will increase the number of fields with at

least two epochs of data. This will reduce our uncertainties

correspondingly, so that we can better address whether the Clouds are

indeed bound to each other and to the Milky Way. It will also allow us

to constrain the internal motions of various populations within the

Clouds, and will allow us to determine a distance to the LMC using

rotational parallax.

ACS/SBC 11151

Evaluating the Role of Photoevaporation of Protoplanetary Disk Dispersal

Emission produced by accretion onto the central star leads to

photoevaporation, which may play a fundamental role in disk dispersal.

Models of disk photoevaporation by the central star are challenged by

two potential problems: the emission produced by accretion will be

substantially weaker for low-mass stars, and photoevaporation must

continue as accretion slows. Existing FUV spectra of CTTSs are biased to

solar-mass stars with high accretion rates, and are therefore

insufficient to address these problems. We propose use HST/ACS SBC

PR130L to obtain FUV spectra of WTTSs and of CTTSs at low masses and

mass accretion rates to provide crucial data to evaluate

photoevaporation models. We will estimate the FUV and EUV luminosities

of low-mass CTTSs with small mass accretion rates, CTTSs with transition

disks and slowed accretion, and of magnetically-active WTTSs.

WFPC2 11130

AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge

Paradigm, Part II

The recent progress in the study of central black holes in galactic

nuclei has led to a general consensus that supermassive {10^6-10^9 solar

mass} black holes are closely connected with the formation and

evolutionary history of large galaxies, especially their bulge

component. Two outstanding issues, however, remain unresolved. Can

central black holes form in the absence of a bulge? And does the mass

function of central black holes extend below 10^6 solar masses?

Intermediate-mass black holes {<10^6 solar masses}, if they exist, may

offer important clues to the nature of the seeds of supermassive black

holes. Using the SDSS, our group has successfully uncovered a new

population of AGNs with intermediate-mass black holes that reside in

low-luminosity galaxies. However, very little is known about the

detailed morphologies or structural parameters of the host galaxies

themselves, including the crucial question of whether they have bulges

or not. Surprisingly, the majority of the targets of our Cycle 14 pilot

program have structural properties similar to dwarf elliptical galaxies.

The statistics from this initial study, however, are really too sparse

to reach definitive conclusions on this important new class of black

holes. We wish to extend this study to a larger sample, by using the

Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175

AGNs with intermediate- mass black holes selected from our final SDSS

search. We are particularly keen to determine whether the hosts contain

bulges, and if so, how the fundamental plane properties of the host

depend on the mass of their central black holes. We will also

investigate the environment of this unique class of AGNs.

WFPC2 11113

Binaries in the Kuiper Belt: Probes of Solar System Formation and

Evolution

The discovery of binaries in the Kuiper Belt and related small body

populations is powering a revolutionary step forward in the study of

this remote region. Three quarters of the known binaries in the Kuiper

Belt have been discovered with HST, most by our snapshot surveys. The

statistics derived from this work are beginning to yield surprising and

unexpected results. We have found a strong concentration of binaries

among low-inclination Classicals, a possible size cutoff to binaries

among the Centaurs, an apparent preference for nearly equal mass

binaries, and a strong increase in the number of binaries at small

separations. We propose to continue this successful program in Cycle 16;

we expect to discover at least 13 new binary systems, targeted to

subgroups where these discoveries can have the greatest impact.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey of

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

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

and Cycle15 these systems frequently exhibit strong gravitational

lensing as well as spectacular examples of violent galaxy interactions.

The proposed observations will provide important constraints on the

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

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

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

science goals require only the detection and characterization of

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

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

compact angular scale our target clusters are less adversely affected by

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

Acknowledging the broad community interest in this sample we waive our

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

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

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

at Cycle16 priority is of paramount importance to reach meaningful

statistics.

WFPC2 10880

The host galaxies of QSO2s: AGN feeding and evolution at high

luminosities

Now that the presence of supermassive black holes in the nuclei of

galaxies is a well established fact, other questions related to the AGN

phenomena still have to be answered. Problems of particular interest are

how the AGN gets fed, how the black hole evolves and how the evolution

of the black hole is related to the evolution of the galaxy bulge. Here

we propose to address some of these issues using ACS/WFC + F775W

snapshot images of 73 QSO2s with redshifts in the range 0.3<z<0.4. These

observations will be combined with similar archival data of QSO1s and

ground based data of Seyfert and normal galaxies. First, we will

investigate whether interactions are the most important feeding

mechanism in high luminosity AGNs. This will be done in a quantitative

way, comparing the asymmetry indices of QSO2 hosts with those of lower

luminosity AGNs and normal galaxies. Second, we will do a detailed study

of the morphology of the host galaxies of both QSO types, to determine

if they are similar, or if there is an evolutionary trend from QSO2s to

QSO1s. The results from this project will represent an important step in

the understanding of AGN evolution, and may also introduce a substantial

modification to the Unified Model.

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for

supernovae {SNe}, most notably our Lick Observatory Supernova Search

{LOSS}, have found hundreds of SNe, many of them in quite nearby

galaxies {cz < 4000 km/s}. Most of the objects were discovered before

maximum brightness, and have follow-up photometry and spectroscopy; they

include some of the best-studied SNe to date. We propose to conduct a

snapshot imaging survey of the sites of some of these nearby objects, to

obtain late-time photometry that {through the shape of the light and

color curves} will help reveal the origin of their lingering energy. The

images will also provide high-resolution information on the local

environments of SNe that are far superior to what we can procure from

the ground. For example, we will obtain color-color and color-magnitude

diagrams of stars in these SN sites, to determine the SN progenitor

masses and constraints on the reddening. Recovery of the SNe in the new

HST images will also allow us to actually pinpoint their progenitor

stars in cases where pre- explosion images exist in the HST archive.

This proposal is an extension of our successful Cycle 13 snapshot survey

with ACS. It is complementary to our Cycle 15 archival proposal, which

is a continuation of our long-standing program to use existing HST

images to glean information about SN environments.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS:

11586 - GSAcq(1,2,1) failed to RGA Hold, search radius limit exceeded on FGS-2

           GSAcq(1,2,1) scheduled at 331/10:59:34z and REAcq(1,2,1) scheduled at

           331/12:33:48 failed to RGA Hold with QF2SRLEX, QF2STOPF, QSRCHEXC and

           QSTOP indication flags set on FGS-2.

           Observations affected: WFPC2 #76-79, Proposal ID #11103.

11588 - GSAcq(2,1,2) failed to RGA hold

           GSAcq 2,1,2 scheduled from 332/01:18:44 - 01:26:10 failed to RGA Hold at

           332/01:21:43 due to QF2STOPF flag on FGS 2.

           Observations affected: WFPC 92-93 Proposal #10880

11590 - GSAcq (1,3,1) failed to RGA Hold due to QF1STOPF on FGS-1

           At 334/02:58:55 GSAcq 1,3,1 scheduled from 02:55:18 - 03:02:42 failed to

           RGA Hold due to QF1STOPF flag on FGS-1.

           Observations affected: ACS #4, Proposal #11230

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                        SCHEDULED      SUCCESSFUL

FGS GSacq                50                  47   

FGS REacq                16                  15               

OBAD with Maneuver 112                 111               

SIGNIFICANT EVENTS: (None)