The intergalactic magnetic field constrained by Fermi/LAT observations of the TeV blazar 1ES 0229+200

By F. Tavecchio, G. Ghisellini, L. Foschini, G. Bonnoli, G. Ghirlanda, P. Coppi. 2010

242 citations recorded by the source corpus.

TeV photons from blazars at relatively large distances, interacting with the optical-IR cosmic background, are efficiently converted into electron-positron pairs. The produced pairs are extremely relativistic (Lorentz factors of the order of 1e6 1e7 and promptly loose their energy through inverse Compton scatterings with the photons of the microwave cosmic background, producing emission in the GeV band. The spectrum and the flux level of this reprocessed emission is critically dependent on the intensity of the intergalactic magnetic field, B, that can deflect the pairs diluting the intrinsic emission over a large solid angle. We derive a simple relation for the reprocessed spectrum expected from a steady source. We apply this treatment to the blazar 1ES 0229+200, whose intrinsic very hard TeV spectrum is expected to be approximately steady. Comparing the predicted reprocessed emission with the upper limits measured by the Fermi/Large Area Telescope, we constrain the value of the intergalactic magnetic field to be larger than $B \simeq 5\times 10^{-15}$ Gauss, depending on the model of extragalactic background light.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4daa49141ec564376fdf2279f4286d1180e9616b

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In Nuclear and High Energy Physics

Citations in the corpus

THE GENERATION OF STRONG MAGNETIC FIELDS DURING THE FORMATION OF THE FIRST STARS (2010, methodology): “However, recent FERMI observations [11] provide a lower limit of 10−15 G for the magnetic field strength in the intergalactic medium (IGM), consistent with the predicted field strength from Biermann battery mechanism at a redshift of z ∼ 10 [12].”
Cosmological Magnetic Fields: Their Generation, Evolution and Observation (2013, background): “…clusters (Clarke et al 2001; Bonafede et al 2010; Feretti et al 2012), in superclusters (Xu et al 2006) and even in voids of the Large Scale Structure (LSS) (Neronov and Vovk 2010; Dolag et al 2011; Tavecchio et al 2011; Tavecchio et al 2010b; Vovk et al 2012; Taylor et al 2011; Dermer et al 2011).”
Physics potential of the International Axion Observatory (IAXO) (2019, background): “The magnitude of primordial intergalactic fields is unknown, but lies between 10−9 and 10−16 G [169].”