Universal bolometric corrections for active galactic nuclei over seven luminosity decades

¹ Dipartimento di Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
e-mail: federicaduras@gmail.com
² Osservatorio Astronomico di Roma – INAF, Via Frascati 33, 00040 Monteporzio Catone, Italy
³ Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France
⁴ Instituto de Astrofísica and Centro de Astroingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
⁵ Department of Physics and Astronomy, University of Southampton, Highfield SO17 1BJ, UK
⁶ Dipartimento di Fisica e Astronomia, Università di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
⁷ Osservatorio Astrofisico di Arcetri – INAF, 50125 Firenze, Italy
⁸ Osservatorio Astronomico di Trieste – INAF, Via Tiepolo 11, 34143 Trieste, Italy
⁹ INAF – Osservatorio Astronomico di Trieste, Via G. Tiepolo 11, 34124 Trieste, Italy
¹⁰ Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Ave., Cambridge CB3 0HE, UK
¹¹ Istituto di Astrofisica e Planetologia Spaziali (INAF), Via del Fosso del Cavaliere 100, Roma 00133, Italy
¹² European Southern Observatory, Santiago, Chile
¹³ Dipartimento di Fisica, Università di Roma La Sapienza, 00185 Roma, Italy
¹⁴ Dipartimento di Fisica e Astronomia, Alma Mater Studiorum, Università degli Studi di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
¹⁵ Osservatorio di Astrofisica e Scienza dello Spazio di Bologna – INAF, Via Gobetti 93/3, 40129 Bologna, Italy

Received: 1 October 2019
Accepted: 24 January 2020

Abstract

Context. The AGN bolometric correction is a key element for understanding black hole (BH) demographics and computing accurate BH accretion histories from AGN luminosities. However, current estimates still differ from each other by up to a factor of two to three, and rely on extrapolations at the lowest and highest luminosities.

Aims. Here we revisit this fundamental question by presenting general hard X-ray (K_X) and optical (K_O) bolometric corrections, computed by combining several AGN samples spanning the widest (about 7 dex) luminosity range ever used for this type of studies.

Methods. We analysed a total of ∼1000 type 1 and type 2 AGN for which we performed a dedicated SED-fitting.

Results. We provide a bolometric correction separately for type 1 and type 2 AGN; the two bolometric corrections agree in the overlapping luminosity range. Based on this we computed for the first time a universal bolometric correction for the whole AGN sample (both type 1 and type 2). We found that K_X is fairly constant at log(L_BOL/L_⊙) < 11, while it increases up to about one order of magnitude at log(L_BOL/L_⊙) ∼ 14.5. A similar increasing trend has been observed when its dependence on either the Eddington ratio or the BH mass is considered, while no dependence on redshift up to z ∼ 3.5 has been found. In contrast, the optical bolometric correction appears to be fairly constant (i.e. K_O ∼ 5) regardless of the independent variable. We also verified that our bolometric corrections correctly predict the AGN bolometric luminosity functions. According to this analysis, our bolometric corrections can be applied to the whole AGN population in a wide range of luminosity and redshift.