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Astron. Astrophys. 345, L32-L34 (1999)

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Letter to the Editor

Pulsar radiation and quantum gravity

Philip Kaaret

Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA (pkaaret@cfa.harvard.edu)

Received 21 December 1998 / Accepted 29 March 1999


Quantum gravity may lead to an energy dependence in the speed of light. The high energy radiation from gamma-ray pulsars can be used to place limits on such effects. We find that emission from the Crab pulsar at energies above 2 GeV trails that at 70-100 MeV by no more than 0.35 ms (95% confidence) and place a lower bound on the energy scale of quantum gravitational effects on the speed of light of [FORMULA]. This bound might be improved by two orders of magnitude by observation of pulsations from the Crab at higher energies, 50-100 GeV, in the near future.

Key words: gravitation – stars: pulsars: general – stars: pulsars: individual: Crab – gamma rays: observations

© European Southern Observatory (ESO) 1999

Online publication: April 19, 1999