# A gamma-ray determination of the Universe’s star formation history

Abstract : The light emitted by all galaxies over the history of the Universe produces the extragalactic background light (EBL) at ultraviolet, optical, and infrared wavelengths. The EBL is a source of opacity for $\gamma$ rays via photon-photon interactions, leaving an imprint in the spectra of distant $\gamma$-ray sources. We measure this attenuation using {739} active galaxies and one gamma-ray burst detected by the {\it Fermi} Large Area Telescope. This allows us to reconstruct the evolution of the EBL and determine the star-formation history of the Universe over 90\% of cosmic time. Our star-formation history is consistent with independent measurements from galaxy surveys, peaking at redshift $z\sim2$. Upper limits of the EBL at the epoch of re-ionization suggest a turnover in the abundance of faint galaxies at $z\sim 6$.
Type de document :
Article dans une revue
Science, 2018, 362 (6418), pp.1031-1034. 〈10.1126/science.aat8123〉
Domaine :

https://hal.archives-ouvertes.fr/hal-01991332
Contributeur : Inspire Hep <>
Soumis le : mercredi 23 janvier 2019 - 17:58:46
Dernière modification le : mercredi 13 février 2019 - 14:54:35

### Citation

S. Abdollahi, M. Ackermann, W.B. Atwood, L. Baldini, J. Ballet, et al.. A gamma-ray determination of the Universe’s star formation history. Science, 2018, 362 (6418), pp.1031-1034. 〈10.1126/science.aat8123〉. 〈hal-01991332〉

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