Talk detail

Participant	Fraschetti, Federico
Institution	Harvard/Smithsonian Center for Astrophysics - 60 Garden St - Cambridge - Massachusetts - USA

Session	HE1	Accepted		Order	Time
Talk	Oral abstract	Title	Model of the broadband Crab nebula spectrum with a log-parabola electron distribution at the wind termination shock
Coauthors
Abstract	A model of the steady-state spectrum of the Crab nebula encompassing the broadband observations from the radio up to the multi-TeV has been recently proposed. TeV electrons are injected at the wind termination shock with a log-parabola momentum distribution and evolved via energy losses. We find an impressive agreement with the observations in the synchrotron region. Moreover, the predicted synchrotron self-Compton accommodates the previously unsolved origin of the broad 200 GeV peak that matches the Fermi/LAT data beyond 1 GeV with the MAGIC data. A log-parabola distribution results from general arguments on the acceleration and escape of the most energetic electrons at a shock wave; in addition, it provides us with a natural interpretation of the deviation from a power-law customarily fit with empirical broken power-laws. Moreover, a log-parabola is consistent with a significant fraction of galactic Fermi/LAT sources. Such model is being applied to the broadband spectra of a variety of astrophysical outflows, including pulsar wind nebulae, supernova remnants and interplanetary shocks. We also show that energetic particles at interplanetary shocks typically fitted with broken-power laws or Band function can be accurately reproduced by log-parabolas.
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