BASS. XXXIII. Swift-BAT Blazars and Their Jets through Cosmic Time

L. Marcotulli*, M. Ajello, C. M. Urry, V. S. Paliya, M. Koss, K. Oh, G. Madejski, Y. Ueda, M. Baloković, B. Trakhtenbrot, F. Ricci, C. Ricci, D. Stern, F. Harrison, M. C. Powell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We derive the most up-to-date Swift-Burst Alert Telescope (BAT) blazar luminosity function in the 14-195 keV range, making use of a clean sample of 118 blazars detected in the BAT 105 month survey catalog, with newly obtained redshifts from the BAT Active Galatic Nucleus Spectroscopic Survey. We determine the best-fit X-ray luminosity function for the whole blazar population, as well as for flat-spectrum radio quasars (FSRQs) alone. The main results are: (1) at any redshift, BAT detects the most luminous blazars, above any possible break in their luminosity distribution, which means we cannot differentiate between density and luminosity evolution; (2) the whole blazar population, dominated by FSRQs, evolves positively up to redshift z ∼ 4.3, confirming earlier results and implying lower number densities of blazars at higher redshifts than previously estimated. The contribution of this source class to the cosmic X-ray background at 14-195 keV can range from 5%-18%, while possibly accounting for 100% of the MeV background. We also derived the average 14 keV-10 GeV spectral energy distribution for BAT blazars, which allows us to predict the number counts of sources in the MeV range, as well as the expected number of high-energy (>100 TeV) neutrinos. A mission like COSI will detect 40 MeV blazars, of which two may have coincident neutrino detections. Finally, taking into account beaming selection effects, the distribution and properties of the parent population of these extragalactic jets are derived. We find that the distribution of viewing angles is quite narrow, with most sources aligned within <5° of the line of sight. Moreover, the average Lorentz factor, 〈Γ〉 = 8-12, is lower than previously suggested for these powerful sources.

Original languageEnglish
Article number77
JournalAstrophysical Journal
Volume940
Issue number1
DOIs
StatePublished - 1 Nov 2022

Funding

FundersFunder number
Fondecyt IniciacionFB210003, 11190831
YCAA
U.S. Department of Energy
National Aeronautics and Space Administration80NSSC20K0044, HST-HF2-51486.001-A, NNH16CT03C
Horizon 2020 Framework Programme950533
Space Telescope Science InstituteNAS5-26555
European Research Council
Ministry of Education, Culture, Sports, Science and Technology
Swedish National Space Agency
Korea Astronomy and Space Science Institute2022-1-868-04
National Research Foundation of KoreaNRF-2020R1C1C1005462
Israel Science Foundation1849/19
Agenzia Spaziale Italiana
Instituto Nazionale di Fisica Nucleare
Japan Aerospace Exploration Agency
Knut och Alice Wallenbergs Stiftelse
Vetenskapsrådet
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
High Energy Accelerator Research Organization
Institut National de Physique Nucléaire et de Physique des Particules

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