Local AGN survey (LASr): I. Galaxy sample, infrared colour selection, and predictions for AGN within 100 Mpc

Asmus, D.; Greenwell, C. L.; Gandhi, P.; Boorman, P. G.; Aird, J.; Alexander, D. M.; Assef, R. J.; Baldi, R. D.; Davies, R., I; Honig, S. F.; Ricci, C.; Rosario, D. J.; Salvato, M.; Shankar, F.; Stern, D.

Abstract

To answer major questions on supermassive black hole (SMBH) and galaxy evolution, a complete census of SMBH growth, i.e. active galactic nuclei (AGN), is required. Thanks to all-sky surveys by the Wide-field Infrared Survey Explorer (WISE) and the Spectrum-Roentgen-Gamma (SRG) missions, this task is now feasible in the nearby Universe. We present a new survey, the Local AGN Survey (LASr), with the goal of identifying AGN unbiased against obscuration and determining the intrinsic Compton-thick (CT) fraction. We construct the most complete all-sky galaxy sample within 100 Mpc (90 per cent completeness for log (M-*/M-circle dot) similar to 9.4), four times deeper than the current reference, the Two Micron All-Sky Survey Redshift Survey (2MRS), which misses similar to 20 per cent of known luminous AGN. These 49k galaxies serve as parent sample for LASr, called LASr-GPS. It contains 4.3k already known AGN, >= 82 per cent of these are estimated to have L-nuc(12 mu m) < 10(42.3) erg s(-1), i.e. are low-luminosity AGN. As a first method for identifying Seyfert-like AGN, we use WISE-based infrared colours, finding 221 galaxies at L-nuc(12 mu m) >= 10(42.3) erg s(-1) to host an AGN at 90 per cent reliability. This includes 61 new AGN candidates and implies an optical type 2 fraction of 50-71 per cent. We quantify the efficiency of this technique and estimate the total number of AGN with L-int (2-10 keV) >= 10(42) erg s(-1 )in the volume to be 362(-116)(+145) (8.6(-2.8)(+)(3.5) x 10(-5) Mpc(-3)). X-ray brightness estimates indicate the CT fraction to be 40-55 per cent to explain the Swift non-detections of the infrared selected objects. One third of the AGN within 100 Mpc remain to be identified, and we discuss the prospects for the eROSITA all-sky survey to detect them.

Más información

Título según WOS: Local AGN survey (LASr): I. Galaxy sample, infrared colour selection, and predictions for AGN within 100 Mpc
Título de la Revista: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volumen: 494
Número: 2
Editorial: OXFORD UNIV PRESS
Fecha de publicación: 2020
Página de inicio: 1784
Página final: 1816
DOI:

10.1093/MNRAS/STAA766

Notas: ISI