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The double AGN in NGC 6240 revealed through 3-5 micron spectroscopy

G. Risaliti·E. Sani·R. Maiolino·A. Marconi·S. Berta·V. Braito·R. Della Ceca·A. Franceschini·M. Salvati·.
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Abstract

We present 3-5 micron spectroscopy of the interacting system NGC 6240, showing the presence of two active galactic nuclei. The brightest (southern) nucleus shows up with a starburst-like emission, with a prominent 3.3 micron emission feature. However, the presence of an AGN is revealed by the detection of a broad Br alpha emission line, with a width of ~1,800 km/s. The spectrum of the faintest (northern) nucleus shows typical AGN features, such as a steep continuum and broad absorption features in the M-band. We discuss the physical properties of the dusty absorbers/emitters, and show that in both nuclei the AGN is dominant in the 3-5 micron band, but its contribution to the total luminosity is small (a few percent of the starburst emission).

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G. Risaliti, E. Sani, R. Maiolino, A. Marconi, S. Berta, V. Braito, R. Della Ceca, A. Franceschini, M. Salvati, .. 2005-12-21. The double AGN in NGC 6240 revealed through 3-5 micron spectroscopy. https://doi.org/10.1086/500588

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