LOFAR: science at the longest wavelengths
The LOFAR low-frequency radio interferometer is poised to make exciting discoveries in transient searches, high-energy astrophysics, and cosmology.
The origin of Galactic cosmic rays
N. Prantzos investigates whether the bulk of Galactic cosmic rays can be accounted for by supernovae remnants
A Tale Of Two Stars: Early Results From The Type Ia Supernova SN2011fe (Part II)
Pre-explosion imaging of supernova SN2011fe sheds light on the question of type Ia supernova progenitors.
The EChO Mission
• Paper title: EChO: The Exoplanet Characterization Observatory (arXiv: 1112.2728)• Authors: G. Tinetti et al• First Author’s Affiliation: University College London, London, UK.• Journal: Accepted for Experimental AstronomyOverviewThis paper describes a proposed ESA M-class mission , the 1.5-meter Exoplanet Characterization Observatory (EChO).The idea behind EChO is simple: to provide a dedicated platform for exoplanet characterization, i.e. to figure out what’s in the atmospheres of planets around other stars. Missions like Kepler do a great job at finding extrasolar planets and at estimating their sizes. Most of these worlds can be massed as well, using techniques like radial velocities and transit timing variations. These are fantastic measurements that let us build up a broad picture of the exoplanetary population. However, as Figure 1 shows, mass and radius alone tell us almost nothing about what might be in a planet’s atmosphere, and what conditions on the surface (if it even has one) are like. Understanding atmospheric and surface composition is critical to a complete theory of the formation, evolution and dynamics of planets, as well as in determining whether or not they might be habitable. For example, Earth and Venus share similar masses and radii, but life as we know it would be hard-pressed to exist on the lead-melting surface of Venus!Spectroscopy allows us to break this degeneracy and directly characterize exoplanets. By looking for the spectral imprint of different substances, we can figure out the composition of the atmosphere as well as its temperature structure (if a feature is observed in absorption, then that substance is hotter deeper in the atmosphere; if in emission, then the opposite is true).EChO proposes...A Tale Of Two Stars: Early Results From The Type Ia Supernova SN2011fe (Part I)
Those watching the sky in August may have heard the news that a new star had appeared: the type Ia supernova PTF11kly (later rechristened SN2011fe) had touched off in M101, the Pinwheel Galaxy, a bare 6.4 Mpc away; close enough that for a brief period the supernova was visible to anyone with a good pair of binoculars. As the closest recent type Ia observed, astronomers were able to use it to place the first direct observational constraints on the progenitor of a type Ia supernova.
How Type II Supernovae Kick Neutron Stars
Nordhaus et al perform simulations to show that normal type II supernovae can produce pulsar kicks which match the observed velocities of neutron stars.