HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT      #4741

 

PERIOD COVERED: 5am November 19 - 5am November 20, 2008 (DOY

                           324/1000z-325/1000z)

 

OBSERVATIONS SCHEDULED

 

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.

 

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 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.

 

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.

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

11581 - GSAcq (2,1,1) Loss of Lock while guiding

           Following successful GSAcq(2,1,1) scheduled at 325/01:29:17 a Loss of

           Lock occurred while guiding with FGS2 and FGS1 at 325/01:36:47.

 

           Observations affected: WFPC 151 thru 174, Proposal ID# 11316.

 

 

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                       SCHEDULED      SUCCESSFUL      FAILURE TIMES

FGS GSacq               14                  14               

FGS REacq               01                   01               

OBAD with Maneuver 30                   29       

LOSS of LOCK                                                       325/0136z

 

SIGNIFICANT EVENTS: (None)