Abstract
From the SDSS DR7 we took a sample of 16733 galaxies which do not show all of the emission lines required to classify their activity according to the classical BPT diagram (Baldwin et al. 1981 PASP). Since they do not show these emission lines they are thought to be AGNs evolved enough so to host very massive Black Holes. We analyzed them in the IR region (WISE data) with the use of a new Infra Red Diagnostic Diagram (IRDD) (Coziol et al. 2015 AJ) and found that their position in the IR color space (W3W4 vs W2W3) corresponds to AGN activity with current low SF. We also found that the masses of the Black holes hosted by them are of the order of 109 M⊙. We then considered a subsample of nearby galaxies from the CALIFA survey DR3 (Sánchez et al. 2015) and using different apertures we estimate the velocity dispersion (using the Starlight code, Cid-Fernandez et al. 2005) and then the BH mass. Comparing these results with the pothometry (GALFIT code, Peng et al. 2003) for the same sample we observe that the estimated masses measured with both methods differ in almost 2 orders of magnitude (López-Cruz et al. 2014, Rusli et al. 2013). By using the IRDD we confirm that these galaxies are AGNs with low SF and host very massive black holes. Nevertheless, the photometry scaling relations should be reviewed to fully explain the big difference with the estimations of spectroscopic methods.
