An image of the dust sublimation region in the nucleus of NGC 1068^⋆

¹ Max Planck Institute for Extraterrestrial Physics(MPE), Giessenbachstr.1, 85748 Garching, Germany
e-mail: davies@mpe.mpg.de
² LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
³ I. Institute of Physics, University of Cologne, Zülpicher Straße 77, 50937 Cologne, Germany
⁴ Departments of Physics and Astronomy, Le Conte Hall, University of California, Berkeley, CA 94720, USA
⁵ Department of Physics and Astronomy, University of Southampton, Southampton, UK
⁶ Department of Physics, Kyoto Sangyo University, Kita-ku, Japan
⁷ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
⁸ School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
⁹ Department of Astronomy, The Ohio State University, Columbus, OH, USA
¹⁰ Center for Cosmology and AstroParticle Physics, The Ohio State University, Columbus, OH, USA
¹¹ Space Telescope Science Institute, Baltimore, MD, USA
¹² Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹³ School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
¹⁴ Center for Computational Astrophysics, Flatiron Institute, 162 5th Ave., New York, NY 10010, USA
¹⁵ European Southern Observatory, Casilla 19001, Santiago 19, Chile
¹⁶ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹⁷ Sterrewacht Leiden, Leiden University, Postbus 9513, 2300, RA Leiden, The Netherlands
¹⁸ Max Planck Institute for Radio Astronomy, Bonn, Germany
¹⁹ Universidade de Lisboa – Faculdade de Ciências, Campo Grande, 1749-016 Lisboa, Portugal
²⁰ Faculdade de Engenharia, Universidade do Porto, rua Dr. Roberto Frias, 4200-465 Porto, Portugal
²¹ CENTRA – Centro de Astrofísica e Gravitação, IST, Universidade de Lisboa, 1049-001 Lisboa, Portugal
²² Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
²³ Instituto de Astrofísica de Canarias (IAC), 38200 La Laguna, Tenerife, Spain

Received: 5 July 2019
Accepted: 1 December 2019

Abstract

We present near-infrared interferometric data on the Seyfert 2 galaxy NGC 1068, obtained with the GRAVITY instrument on the European Southern Observatory Very Large Telescope Interferometer. The extensive baseline coverage from 5 to 60 Mλ allowed us to reconstruct a continuum image of the nucleus with an unrivaled 0.2 pc resolution in the K-band. We find a thin ring-like structure of emission with a radius r = 0.24 ± 0.03 pc, inclination i = 70 ± 5°, position angle PA = −50 ± 4°, and h/r <  0.14, which we associate with the dust sublimation region. The observed morphology is inconsistent with the expected signatures of a geometrically and optically thick torus. Instead, the infrared emission shows a striking resemblance to the 22 GHz maser disc, which suggests they share a common region of origin. The near-infrared spectral energy distribution indicates a bolometric luminosity of (0.4–4.7) × 10⁴⁵ erg s⁻¹, behind a large A_K ≈ 5.5 (A_V ≈ 90) screen of extinction that also appears to contribute significantly to obscuring the broad line region.