[FeX]{lambda}6374 em. in SDSS dwarf galaxies

However, traditional optical searches for active galactic nuclei (AGNs) only reliably detect high-accretion, relatively high-mass BHs in dwarf galaxies with low amounts of star formation, leaving a large portion of the overall BH population in dwarf galaxies relatively unexplored. Here, we present a sample of 81 dwarf galaxies (M_*_<=3x10^9^M_{sun}_) with detectable [FeX]{lambda}6374 coronal line emission indicative of accretion onto massive BHs, only two of which were previously identified as optical AGNs.

We analyze optical spectroscopy from the Sloan Digital Sky Survey and find [FeX]{lambda}6374 luminosities in the range L_[FeX]_~10^36^-10^39^erg/s, with a median value of 1.6x10^38^erg/s. The [FeX]{lambda}6374 luminosities are generally much too high to be produced by stellar sources, including luminous Type IIn supernovae (SNe). Moreover, based on known SNe rates, we expect at most eight Type IIn SNe in our sample.