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The Close Environment of Seyfert Galaxies and Its Implication for Unification Models

D. Dultzin-Hacyan·Y. Krongold·I. Fuentes-Guridi·P. Marziani
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Abstract

This paper presents a statistical analysis of the circumgalactic environment of nearby Seyfert galaxies based on a computer-aided search of companion galaxies on the Digitized Sky Survey (DSS). An intrinsic difference between the environment of Seyfert 1 and Seyfert 2 galaxies, suggested by previous work, is confirmed as statistically significant. For Seyfert 2 galaxies we find a significant excess of large companions (diameter of companion >= 10 Kpc) within a search radius <= 100 Kpc of projected linear distance, as well as within a search radius equal to three times the diameter \ds of each Seyfert galaxy. For Seyfert 1 galaxies there is no clear evidence of any excess of companion galaxies neither within 100 Kpc, nor within 3\ds. For all samples the number of companions suggests a markedly non-Poissonian distribution for galaxies on scales <= 100 Kpc. This difference in environment is not compatible with the simplest formulation of the Unification Model for Seyferts: both types 1 and 2 should be intrinsicaly alike, the only difference being due to orientation of an obscuring torus. We propose an alternative formulation.

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D. Dultzin-Hacyan, Y. Krongold, I. Fuentes-Guridi, P. Marziani. 1999-01-18. The Close Environment of Seyfert Galaxies and Its Implication for Unification Models. https://doi.org/10.1086/311925

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