WISE2MBH: a scaling-based algorithm for probing supermassive black hole masses through WISE catalogues

Abstract

ABSTRACT Supermassive Black Holes (SMBHs) are commonly found at the centres of massive galaxies. Estimating their masses (MBH) is crucial for understanding galaxy-SMBH co-evolution. We present WISE2MBH, an efficient algorithm that uses cataloged Wide-field Infrared Survey Explorer (WISE) magnitudes to estimate total stellar mass (M*) and scale this to bulge mass (MBulge), and MBH, estimating the morphological type (TType) and bulge fraction (B/T) in the process. WISE2MBH uses scaling relations from the literature or developed in this work, providing a streamlined approach to derive these parameters. It also distinguishes QSOs from galaxies and estimates the galaxy TType using WISE colours with a relation trained with galaxies from the 2MASS Redshift Survey. WISE2MBH performs well up to z ∼ 0.5 thanks to K-corrections in magnitudes and colours. WISE2MBH MBH estimates agree very well with those of a selected sample of local galaxies with MBH measurements or reliable estimates: a Spearman score of ∼0.8 and a RMSE of ∼0.63 were obtained. When applied to the ETHER sample at z ≤ 0.5, WISE2MBH provides ∼1.9 million MBH estimates (78.5 per cent new) and ∼100 thousand upper limits. The derived local black hole mass function (BHMF) is in good agreement with existing literature BHMFs. Galaxy demographic projects, including target selection for the Event Horizon Telescope, can benefit from WISE2MBH for up-to-date galaxy parameters and MBH estimates. The WISE2MBH algorithm is publicly available on GitHub.