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 measured this attenuation using 739 active galaxies and one gamma-ray burst detected by the Fermi Large Area Telescope. This allowed 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 ~ 2. Upper limits of the EBL at the epoch of reionization suggest a turnover in the abundance of faint galaxies at z ~ 6.
A gamma-ray determination of the Universe's star formation history / Abdollahi, S., Ackermann, M., Ajello, M., Atwood, W.b., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Gonzalez, J.b., Bellazzini, R., Bissaldi, E., Blandford, R.d., Bloom, E.d., Bonino, R., Bottacini, E., Buson, S., Bregeon, J., Bruel, P., Buehler, R., Cameron, R.a., et al.. - In: SCIENCE. - ISSN 0036-8075. - STAMPA. - 362:6418(2018), pp. 1031-1034. [10.1126/science.aat8123]
A gamma-ray determination of the Universe's star formation history
Bissaldi, EMembro del Collaboration Group
;Favuzzi, CMembro del Collaboration Group
;Giglietto, NMembro del Collaboration Group
;
2018
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 measured this attenuation using 739 active galaxies and one gamma-ray burst detected by the Fermi Large Area Telescope. This allowed 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 ~ 2. Upper limits of the EBL at the epoch of reionization suggest a turnover in the abundance of faint galaxies at z ~ 6.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
