Study of Time Lags inHETE‐2Gamma‐Ray Bursts with Redshift: Search for Astrophysical Effects and a Quantum Gravity Signature

Abstract

The study of time lags between spikes in Gamma-Ray Bursts light curves in different energy bands as a function of redshift may lead to the detection of effects due to Quantum Gravity. We present an analysis of 15 Gamma-Ray Bursts with measured redshift, detected by the HETE-2 mission between 2001 and 2006 in order to measure time lags related to astrophysical effects and search for Quantum Gravity signature in the framework of an extra-dimension string model. The use of photon-tagged data allows us to consider various energy ranges. Systematic effects due to selection and cuts are evaluated. No significant Quantum Gravity effect is detected from the study of the maxima of the light curves and a lower limit at 95% Confidence Level on the Quantum Gravity scale parameter of 3.2 × 10 15 GeV is set.

Study of Lorentz violation in INTEGRAL gamma-ray bursts

“…Such a rescaling has also been proposed in [35,36,37] Figure 4 (right panel) presents the dependence of the rescaled χ 2 /d.o.f as a function of M . The minimum of this function is found at M ≃ 3.8 · 10…”

“…In [36] and [37] a linear fit was obtained by using not z as the independent variable but instead a function K(z). Dividing (9) by (1 + z), K(z) is given by the non-linear function…”

“…It was pointed out that one powerful way to probe Equation (2) may be provided by gamma-ray bursts (GRBs) [33,34]. Several studies have been conducted using measurements of GRBs [35,36,37]. GRBs are the most distant variable astrophysical sources of energetic photons detected by present experiments in the energy range from keV to GeV.…”

“…Contrary to previous studies [35,36,37,49,50] where a binning in time and energy was used, we use unbinned data, i.e. we know the arrival time and energy of every single photon detected by the satellite.…”

Limits on an Energy Dependence of the Speed of Light from a Flare of the Active Galaxy PKS 2155-304

“…For the linear dispersion term in Eq. (1), these measurements reach limits of jj < 70-150 [10][11][12][13][14][15] for gamma-ray bursts. For active galaxies, dispersion measurements exist for only two sources: Mkn 421 and Mkn 501.…”