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  • The Host Galaxy of OJ 287 R...
    Nilsson, K.; Kotilainen, J.; Valtonen, M.; Gomez, J. L.; Castro-Tirado, A. J.; Drozdz, M.; Gopakumar, A.; Jeong, S.; Kidger, M.; Komossa, S.; Mathur, S.; Park, I. H.; Reichart, D. E.; Zola, S.

    The Astrophysical journal, 12/2020, Letnik: 904, Številka: 2
    Journal Article

    The BL Lacertae object OJ 287 (z = 0.306) has unique double-peaked optical outbursts every ∼12 yr, and it presents one of the best cases for a small-separation binary supermassive black hole (SMBH) system, with an extremely massive primary . However, the host galaxy is unresolved or only marginally detected in all optical studies so far, indicating a large deviation from the bulge mass-SMBH mass relation. We have obtained deep, high spatial resolution i-band and K-band images of OJ 287 when the target was in a low state, which enable us to detect the host galaxy. We find the broadband photometry of the host to be consistent with an early-type galaxy with MR = −22.5 and MK = −25.2, placing it in the middle of the host galaxy luminosity distribution of BL Lacertae objects. The central supermassive black hole is clearly overmassive for a host galaxy of that luminosity, but not unprecedented, given some recent findings of other "overmassive" black holes in nearby galaxies.