Linear and circular polarization in GRB afterglows

Lara Nava, Ehud Nakar, Tsvi Piran

Research output: Contribution to journalConference articlepeer-review


A certain degree of linear polarization has been measured in several GRB afterglows. More surprisingly, circular polarization has been recently measured in GRB121024A. For synchrotron emission, the polarization level depends on: (i) the local magnetic field orientation (ii) the geometry of the emitting region with respect to the line of sight and (iii) the electron pitch-angle distribution. For this reason, polarization measurements are a valuable tool to probe afterglow micro-physics. We present numerical estimates of linear and circular polarization for different configurations (i.e., magnetic fields, geometries and pitch-angle distributions). For each different scenario, we study the conditions for reaching the maximum and minimum linear and circular polarization and provide their values. We discuss the implication of our results to the micro-physics of GRB afterglows in view of recent polarization measurements.

Original languageEnglish
Article number018
JournalProceedings of Science
StatePublished - 2014
Event10th Conference on Swift, SWIFT 2014 - Rome, Italy
Duration: 2 Dec 20145 Dec 2014


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