"A Type Ia Supernova at Redshift 1.55 in Hubble Space Telescope InfraredObservations from CANDELS, by Rodney et al."

Bruno Leibundgut (ESO)

Abstract

This is a fairly short paper, but it is the first from the multi-cycle HST program to find the most distant supernovae. I will expand on that a little bit as well.

"Super-Earths and Neptune-mass planets from the HARPS surveys: a window to planetary-system diversity"

Stephane Udry (University of Geneva)

Abstract

I will report on the results of an 8-year survey carried out at the La Silla Observatory with the HARPS spectrograph to detect and characterize planets in the super-Earth and Neptune-mass regime. The size of our star sample and the precision achieved with HARPS have led to the detection of a sufficiently large number of low-mass planets to study the statistical properties of their orbital elements, the correlation of host-star properties with the planet masses, as well as the occurrence rate of planetary systems around solar-type stars. These results will be discussed in comparison with equivalent results obtained in our M-dwarf survey and with the recent Kepler findings.

"Using stellar mass black holes to understand AGN"

Chris Done

Abstract

I will review the spectral and timing properties of x-ray binaries, especially the behaviour seen as the source makes a transition from the low/hard to high/soft state. The broad band spectral evolution is well modelled by a truncated disc/hot inner flow geometry, where the truncation radius moves progressively towards the last stable orbit during the transition. Here I show that this same geometry can also quantatitively match the power spectral evolution, where fluctuations propagating through the hot flow (stirred up by the MRI) make the broad band continuum power spectra, and Lense-Thirring precession of the hot flow makes the prominent low frequency QPO. I will then take some of the insights on accretion in stellar mass black holes and see how they can help in interpreting AGN spectra.

"Three Freaks of the Solar System (And Why They Matter)"

Dave Jewitt

Abstract

In addition to the major planets, the solar system contains a large number of so-called small bodies in dynamically distinct reservoirs. These include the main-belt asteroids, main-belt comets, Trojans, Centaurs, irregular satellites, the comets of the Oort cloud and Kuiper belt, and others. These reservoirs are important both for the relics of solar system formation contained therein, and as sources for short-lived populations in the inner solar system. For the most part, the small body populations were discovered recently, their investigation is still firmly in the exploration phase and much of the excitement in planetary science stems directly from them.

I will use new observations of three "freak" and very surprising objects as a vehicle to discuss the small body populations, to highlight our ignorance of even basic issues in the origin and evolution of the solar system, and to indicate potentially productive paths to future research.

"The Precision Array to Probe the Epoch of Reionization"

Chris Carilli

Abstract

Cosmic reionization is the 'final frontier' in studies of cosmic structure formation, corresponding to the epoch when light from the first stars and black holes act to reionize the neutral intergalactic medium, a few hundred million years after the Big Bang. I will present a summary of the concept of reionization, and exciting recent results that set the first constraints on the epoch of reionization. The latest studies of spectra of the most distant quasars suggest a substantial rise in the neutral fraction at z ~ 7. While revolutionary, current measures of cosmic reionization have serious limitations. The most direct probe of the neutral IGM during reionization is through the 21cm emission line of hydrogen. I will present the design and recent results from the Precision Array to Probe the Epoch of Reionization. PAPER comprises two low frequency dipole arrays (120 to 180 MHz) to study the HI 21cm signal from the neutral IGM during reionization. Our design philosophy is to maintain a simple telescope response in frequency and angle to mitigate the substantial systematic problems that these measurements entail (strong continuum foregrounds, very wide fields, large fractional bandwidths, and strong terrestrial interference). I will present the first all-sky images from our working arrays in the Karoo and Green Bank, details on the processing involved, and plans for expansion to the full science array.

"Dusty nature of quasars"

Bozena Czerny (Copernicus Astronomical Center, Warsaw)

Abstract

The most characteristic property of active galaxies, including quasars, are prominent broad emission lines. These lines allowed to discover the cosmological nature of quasars, and at present they provide the most convenient method of weighting black holes residing in their nuclei. However, a question remains why such strong lines form there in the first place.

I will discuss an interesting possibility that dust is responsible for this phenomenon. The dust is known to be present in quasars in the form of a dusty/molecular torus which results in complexity of the appearance of active galaxies. However, this dust is located further from the black hole than the Broad Line Region. We propose that the dust is present also closer in and it is actually responsible for formation of the broad emission lines. The argument is based on determination of the temperature of the disk atmosphere underlying the Broad Line Region: it is close to 1000 K independently from the black hole mass and accretion rate of the object. The mechanism is simple and universal but leads to a considerable complexity of the active nucleus surrounding. I will conclude with the discussion how this idea fits into the general scheme of the quasar structure.