Unveiling the central parsec region of an AGN: the Circinus nucleus in the near infrared with the VLT

Abstract

VLT J- to M\p-band adaptive optics observations of the Circinus Galaxy on parsec scales resolve a central bright Ks-band source with a FWHM size of 1.9 $\pm$ 0.6 pc. This source is only visible at wavelengths longward of 1.6 $\mu$m and coincides in position with the peak of the [Si VII]~2.48 $\mu$m coronal line emission. With respect to the peak of the central optical emission, the source is shifted by $\sim$ 0.15\arcsec (2.8 pc) to the south-east. Indeed, it defines the vertex of a fairly collimated beam which extends for $\sim$ 10 pc, and which is seen in both continuum light shortward of 1.6 $\mu$m and in H$\alpha$ line emission. The source also lies at the center of a $\sim$ 19 pc size [Si VII] ionization {\it bicone}. Identifying this source as the nucleus of Circinus, its size is compatible with a putative parsec-scale torus. Its spectral energy distribution, characterized by a prominent narrow peak, is compatible with a dust temperature of 300 K. Hotter dust within a 1 pc radius of the center is not detected. The AGN luminosity required to heat this dust is in the range of X-ray luminosities that have been measured toward the central source. This in turn supports the existence of highly obscuring material, with column densities of $10^{24}$ cm${}^{-2}$, that must be located within 1 pc of the core.

15 pages, 4 figures; To appear in The Astrophysical Journal

References in corpus (8)

• The Discovery of H2O Maser Emission in Seven AGN and at High Velocities in the Circinus Galaxy
• Hubble Space Telescope Imaging of the Circinus Galaxy
• The Multitude of Unresolved Continuum Sources at 1.6 microns in Hubble Space Telescope images of Seyfert Galaxies
• A Chandra Observation of the Circinus Galaxy
• Discovery of a nuclear gas bar feeding the active nucleus in Circinus
• Gas and Dust Emission from the Nuclear Region of the Circinus Galaxy
• The Infrared Continuum of Active Galaxies
• Extended Coronal Emission Lines in Active Galactic Nuclei

Cited by in corpus (43)

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• Three-dimensional radiative transfer models of clumpy tori in Seyfert galaxies
• The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus models
• Testing the Unification Model for AGN in the Infrared: are the obscuring tori of Type 1 and 2 Seyferts different?
• Towards a physical model of dust tori in Active Galactic Nuclei - Radiative transfer calculations for a hydrostatic torus model
• The spectral energy distribution of the central parsecs of the nearest AGN
• SINFONI adaptive optics integral field spectroscopy of the Circinus Galaxy
• The Central Kiloparsec of Seyfert and Inactive Host Galaxies: a Comparison of Two-Dimensional Stellar and Gaseous Kinematics
• Dissecting the active galactic nucleus in Circinus -- I. Peculiar mid-IR morphology explained by a dusty hollow cone
• AGN Selection and Demographics in GOODS-S/HUDF from X-ray to Radio
• Obscuration in AGNs: near-infrared luminosity relations and dust colors
• The Near-Infrared Coronal Line Spectrum of 54 Nearby Active Galactic Nuclei
• Time-resolved infrared emission from radiation-driven central obscuring structures in Active Galactic Nuclei
• Extending the M_(bh)-sigma diagram with dense nuclear star clusters
• Mid-infrared, spatially-resolved spectroscopy of the nucleus of the Circinus galaxy
• Morphology of the coronal line region in active galactic nuclei
• The dusty heart of Circinus: I. Imaging the circumnuclear dust in N-band
• The central parsecs of active galactic nuclei: challenges to the torus
• VLT diffraction-limited imaging at 11 and 18 micron of the nearest active galactic nuclei
• The narrow Fe K$\alpha$ line and the molecular torus in active galactic nuclei - an IR/X-ray view
• The continuum and narrow line region of the NLS1 galaxy Mrk 766
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• First Detection of Millimeter/Submillimeter Extragalactic H2O Maser Emission
• The warm molecular gas and dust of Seyfert galaxies: two different phases of accretion?
• The deeply obscured AGN of NGC4945 I. Spitzer-IRS maps of [Ne V], [Ne II], H2 0-0 S(1), S(2), and other tracers
• ALMA imaging of the cold molecular and dusty disk in the type 2 active nucleus of the Circinus galaxy
• The nuclear dust lane of Circinus: collimation without a torus
• Circinus Galaxy Revisted with 10 Years of Fermi-LAT Data
• Can photo-ionization explain the decreasing fraction of X-ray obscured AGN with luminosity?
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• On the equivalent width of the Fe K$\alpha$ line produced by a dusty absorber in active galactic nuclei
• Constraining Torus Models for AGNs Using X-Ray Observations
• Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. III. CRIRES observations of the Circinus galaxy
• Adaptive Optics: Observations and Prospects for Studies of Active Galactic Nuclei
• A Dipole Vortex Model of Obscuring Tori in Active Galaxy Nuclei
• The Spatial Variation of the 3micron Dust Features in Circinus
• Near IR diffraction-limited integral-field SINFONI spectroscopy of the Circinus galaxy
• X-ray and CO-Derived Column Densities in AGN: A Study of Obscuration Properties in CTAGN and Non-CTAGN
• AO assisted spectroscopy with SINFONI: PSF, background, and interpolation
• Hunting Star-Forming Galaxies in the Gamma-Ray Domain