LAUSR

We investigate the spectroscopic properties of 85 brightest cluster galaxies (BCGs) and their companions observed with the SDSS MaNGA integral field unit. Galaxy redshifts are between 0.08 < z < 0.15, allowing for a field of view up to 80 kpc × 80 kpc. For the main galaxies: The average age of the BCG cores is 7.66 ± 1.36 Gyr with no significant gradient out to 2 Re; the average metallicity of the BCG cores is [Z/H] = 0.23 ± 0.03 with a negative gradient of Δ[Z/H]/Δ(R/Re) = -0.14 ± 0.09 which flattens beyond 1.2 Re. Velocity dispersion gradients are mostly flat, but a few positive slopes are seen in the most massive galaxies. Emission lines are present in 12 of the BCGs, most often confined to the central ∼2 kpc with emission line ratios well described by a LINER or AGN excitation source. There are 78 companion galaxies identified and 9 have nebular emission lines that indicate recent star formation. The companions with flux ratios of 4:1 and 20:1 within 30 kpc of their BCG’s core are studied. The companion galaxies have a median age of 7.65 ± 1.55 Gyr and are high metallicity systems, with a median [Z/H] = 0.17  ±  0.07. Close spectroscopic companions with higher merging probabilities have an average merging time of 0.5 ± 0.2 Gyr. The average merger rate is 0.08 ± 0.12 Gyr−1 for 4:1 companions and 0.26 ± 0.22 Gyr−1 for 20:1 companions, allowing for an increase in mass of 2.3 ± 3.4%  Gyr−1 and 3.5 ± 3.2%  Gyr−1, respectively.