AGN luminosity and stellar age : two missing ingredients for AGN unification as seen with iPTF supernovae
Villarroel, Beatriz; Nyholm, Anders; Karlsson, Torgny; Comerón, Sébastien; Korn, Andreas J.; Sollerman, Jesper; Zackrisson, Erik (2017-03-08)
Villarroel, B., Nyholm, A., Karlsson, T., Comerón, S., Korn, A., Sollerman, J., Zackrisson, E. (2017) AGN Luminosity and Stellar Age: Two Missing Ingredients for AGN Unification as Seen with iPTF Supernovae. Astrophysical Journal, 837 (2), 110. doi:10.3847/1538-4357/aa5d5a
© 2017. The American Astronomical Society. All rights reserved. Published in this repository with the kind permission of the publisher.
Active galactic nuclei (AGNs) are extremely powerful cosmic objects, driven by accretion of hot gas upon super-massive black holes. The zoo of AGN classes is divided into two major groups, with Type-1 AGNs displaying broad Balmer emission lines and Type-2 narrow ones. For a long time it was believed that a Type-2 AGN is a Type-1 AGN viewed through a dusty kiloparsec-sized torus, but an emerging body of observations suggests more than just the viewing angle matters. Here we report significant differences in supernova (SN) counts and classes in the first study to date of SNe near Type-1 and Type-2 AGN host galaxies, using data from the intermediate Palomar Transient Factory, the Sloan Digital Sky Survey Data Release 7, and Galaxy Zoo. We detect many more SNe in Type-2 AGN hosts (size of effect ~5.1σ) compared to Type-1 hosts, which shows that the two classes of AGN are located inside host galaxies with different properties. In addition, Type-1 and Type-2 AGNs that are dominated by star formation according to Wide-field Infrared Survey Explorer colors mW1 − mW2 < 0.5 and are matched in 22 μm absolute magnitude differ by a factor of ten in L[O III] λ5007 luminosity, suggesting that when residing in similar types of host galaxies Type-1 AGNs are much more luminous. Our results demonstrate two more factors that play an important role in completing the current picture: the age of stellar populations and the AGN luminosity. This has immediate consequences for understanding the many AGN classes and galaxy evolution.
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