Presentation #213.03 in the session AGN and Quasars III.
The current cosmological paradigm posits that all supermassive black holes (SMBH) originated with seed black holes residing in low mass, metal poor galaxies. As systems evolved and merged, the seed black holes grew into the SMBHs we see today. While these progenitor systems at the earliest epochs remain observationally inaccessible, analogues of such systems do exist in the local Universe. Low-mass, low-metallicity, quiescent (e.g. merger-free) galaxies are an ideal probe for understanding the origins of SMBH seeds. While there has been growing success in recent studies in discovering SMBHs in dwarf galaxies, many of the tools used in these studies are biased against low metallicity and relatively merger-free galaxies, thus missing precisely the demographic in which to search for the relics of SMBH seeds. Here, I will present the detection of the [Si VI]1.963μm coronal line (CL), a robust indicator of an AGN in the galaxy SDSS J160135.95+311353.7, a nearby (z = 0.031) low metallicity galaxy with a stellar mass approximately an order of magnitude lower than the Large Magellanic Cloud, and no optical evidence for an AGN. Further, with the successful launch of JWST, I will highlight the potential of infrared coronal lines as an AGN diagnostic.