Constraints on Lorentz invariance violation from FermiLarge Area Telescope observations of gammaray bursts
Abstract
We analyze the MeV/GeV emission from four bright gammaray bursts (GRBs) observed by the Fermi Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some quantum gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible sourceintrinsic, spectralevolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derive limits on the QG energy scale (the energy scale where LIVinducing QG effects become strong, E_{QG}) and the coefficients of the Standard Model Extension. For the subluminal case (where highenergy photons propagate more slowly than lowerenergy photons) and without taking into account any sourceintrinsic dispersion, our most stringent limits (at 95% C.L.) are obtained from GRB 090510 and are E_{QG,1}>7.6 times the Planck energy (E_{Pl}) and E_{QG,2}>1.3×10^{11}GeV for linear and quadratic leadingorder LIVinduced vacuum dispersion, respectively. These limits improve the latest constraints by Fermi and H.E.S.S. by a factor of ̃2. Our results disfavor any class of models requiring E_{QG,1}≲E_{Pl}.
 Publication:

Physical Review D
 Pub Date:
 June 2013
 DOI:
 10.1103/PhysRevD.87.122001
 arXiv:
 arXiv:1305.3463
 Bibcode:
 2013PhRvD..87l2001V
 Keywords:

 11.30.Cp;
 04.60.m;
 98.70.Rz;
 Lorentz and Poincare invariance;
 Quantum gravity;
 gammaray sources;
 gammaray bursts;
 Astrophysics  High Energy Astrophysical Phenomena;
 Astrophysics  Cosmology and Extragalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 Accepted for publication by Physical Review D