2005/12/21 by G. Risaliti, E. Sani, R. Maiolino +7 · 2 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/500588
published as Astrophys.J.637:L17-20,2006 · 10 pages, 2 figures, accepted for publication in ApJ Letters
arxiv created 2005/12/21 · openalex publication_date 2006/01/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present 3-5 μm spectroscopy of the interacting system NGC 6240, revealing the presence of two active galactic nuclei (AGNs). The brightest (southern) nucleus shows up with a starburst-like emission, with a prominent 3.3 μm emission feature. However, the presence of an AGN is revealed by the detection of a broad Brα emission line, with a width of ~1800 km s -1 . 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 we show that in both nuclei, the AGN is dominant in the 3-5 μm band but that its contribution to the total luminosity is small (a few percent of the starburst emission).