Extreme and high synchrotron peak blazars beyond 4FGL: The 2BIGB gamma-ray catalogue

This paper presents the results of a gamma-ray likelihood analysis over all the extreme and high synchrotron peak blazars (EHSP and HSP) from the 3HSP catalogue. We investigate 2013 multifrequency positions under the eyes of Fermi Large Area Telescope, considering 11 yr of observations in the energy range between 500MeV and 500 GeV, which results in 1160 gamma-ray signatures detected down to the TS = 9 threshold. The detections include 235 additional sources concerning the Fermi Large Area Telescope Fourth Source Catalog (4FGL), all confirmed via high-energy TS (Test Statistic) maps, and represent an improvement of similar to 25 per cent for the number of EHSP and HSP currently described in gamma-rays. We build the gamma-ray spectral energy distribution (SED) for all the 1160 2BIGB sources, plot the corresponding gamma-ray logN-logS, and measure their total contribution to the extragalactic gamma-ray background, which reaches up to similar to 33 per cent at 100 GeV. Also, we show that the gamma-ray detectability improves according to the synchrotron peak flux as represented by the figure of merit parameter, and note that the search for TeV peaked blazars may benefit from considering HSP and EHSP as a whole, instead of EHSPs only. The 2BIGB acronym stands for 'Second Brazil-ICRANet Gamma-ray Blazars' catalogue, and all the broad-band models and SED data points will be available on public data repositories (OpenUniverse, GitHub, and Brazilian Science Data Center-BSDC).