Sesión de debate MFHG del 26/11/2014

Rayos Gamma de Muy Alta Energía
Sala de Juntas
Presentado por:: 
Alberto Domínguez Díaz (IAA-Universidad de Sevilla)

En la sesión CCD de debate del miercoles 26 de noviembre 2008 se han discutido los siguientes dos artículos:

"Very-High-Energy Gamma Rays from a Distant Quasar: How Trasparent Is the Universe?": The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.

"Observation of Pulsed Gamma-Rays Above 25 GeV from the Crab Pulsar with MAGIC": One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar’s spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the MAGIC Cherenkov telescope to 25 GeV. In this configuration we detected pulsed gamma-rays from the Crab pulsar above 25 GeV, revealing a relatively high cut-off energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar cap scenario. The high cutoff also challenges the slot gap model.

La próxima sesión de debate tendrá lugar el día miércoles 10 de diciembre. ¡Os esperamos numerosos!