Narrow-line AGN in the ISO-2MASS survey

Context. A long-standing challenge of observational AGN research is to find type 2 quasars, the luminous analogues of Seyfert-2 galaxies. Aims. We search for luminous narrow-line type 2 AGN, characterise their properties, and compare them with broad-line type 1 AGN. Methods. Combining the ISOCAM parallel survey at 6.7 μ m with 2MASS, we have selected AGN via near-mid-infrared colours caused by the hot nuclear dust emission. We performed spectroscopy in the optical and, for a subset of the sample, also in the mid-infrared with Spitzer. Results. We find nine type 2 AGN at redshift $0.1 0.5$ we did not find type 2 AGN, probably because the hottest dust emission, still covered by the NIR filters, is obscured. The optical spectra of the type 2 host galaxies show young and old stellar populations. Only one object is an ultraluminous infrared galaxy with starburst. The 5–38 μ m spectra of the two type 2 sources observed show a strong continuum with PAH emission in one case and silicate absorption in the other case. Conclusions. The near-mid-infrared selection is a successful strategy to find luminous type 2 AGN at low z . The objects exhibit a large range of properties so that it is difficult to infer details by means of popular SED fitting with simple average templates.