How Special Are Brightest Cluster Galaxies? The Impact of Near-Infrared Luminosities on Scaling Relations for BCGs

Using the extended J, H, and K magnitudes provided by the 2MASS data archive, we consider the position of brightest cluster galaxies (BCGs) in the observed relations between inferred supermassive black hole (SMBH) mass and the host galaxy properties, as well as their position in the stellar velocity dispersion and luminosity (σ*-L) relation, compared to E and S0 galaxies. We find that SMBH masses (M•) derived from near-infrared (NIR) magnitudes do not exceed ~3 × 109 M☉ and that these masses agree well with the predictions made from σ*. In the NIR, there is no evidence that BCGs leave the σ*-L relation defined by less luminous galaxies. The higher SMBH masses predicted from V-band luminosities (M• ≲ 1010.5 M☉) are attributed to the presence of extended envelopes around the BCGs; however, this will need to be confirmed using deeper multiwavelength imaging.