Outflow-Dominated Emission from the Quiescent Massive Black Holes in NGC 4621 and NGC 4697 - AstrophysicsReportar como inadecuado




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Abstract: The nearby elliptical galaxies NGC 4621 and NGC 4697 each host a supermassiveblack hole with a mass more than 1e8 Solar masses. Analysis of archival Chandradata and new NRAO Very Large Array data shows that each galaxy contains alow-luminosity active galactic nucleus LLAGN, identified as a faint, hardX-ray source that is astrometrically coincident with a faint 8.5-GHz source.The latter has a diameter less than 0.3 arcsec 26 pc for NGC 4621, 17 pc forNGC 4697. The black holes energizing these LLAGNs have Eddington ratios L2-10keV - LEdd ~ 1e-9, placing them in the so-called quiescent regime. Theemission from these quiescent black holes is radio-loud, with log Rx = lognuLnu8.5 GHz - L2-10 keV ~ -2, suggesting the presence of a radio outflow.Also, application of the radio-X-ray-mass relation from Yuan and Cui forquiescent black holes predicts the observed radio luminosities nuLnu8.5 GHzto within a factor of a few. Significantly, that relation invokes X-rayemission from the outflow rather than from an accretion flow. The faint, butdetectable, emission from these two massive black holes is therefore consistentwith being outflow-dominated. Observational tests of this finding aresuggested.



Autor: J.M. Wrobel, Y. Terashima, L.C. Ho

Fuente: https://arxiv.org/







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