Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068

Abstract

We present sub-arcsecond 7.5$-$13 $\mu$m imaging- and spectro-polarimetric observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio CANARIAS. At all wavelengths, we find: (1) A 90 $\times$ 60 pc extended polarized feature in the northern ionization cone, with a uniform $\sim$44${}^{\circ }$ polarization angle. Its polarization arises from dust and gas emission in the ionization cone, heated by the active nucleus and jet, and further extinguished by aligned dust grains in the host galaxy. The polarization spectrum of the jet-molecular cloud interaction at $\sim$24 pc from the core is highly polarized, and does not show a silicate feature, suggesting that the dust grains are different from those in the interstellar medium. (2) A southern polarized feature at $\sim$9.6 pc from the core. Its polarization arises from a dust emission component extinguished by a large concentration of dust in the galaxy disc. We cannot distinguish between dust emission from magnetically aligned dust grains directly heated by the jet close to the core, and aligned dust grains in the dusty obscuring material surrounding the central engine. Silicate-like grains reproduce the polarized dust emission in this feature, suggesting different dust compositions in both ionization cones. (3) An upper limit of polarization degree of 0.3 per cent in the core. Based on our polarization model, the expected polarization of the obscuring dusty material is $\lesssim$0.1 per cent in the 8$-$13 $\mu$m wavelength range. This low polarization may be arising from the passage of radiation through aligned dust grains in the shielded edges of the clumps.

arXiv comment17 pages, 10 figures, accepted for publication at MNRAS

References in corpus (38)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• AGN Dusty Tori: II. Observational Implications of Clumpiness
• AGN Dusty Tori: I. Handling of Clumpy Media
• Molecular line emission in NGC1068 imaged with ALMA. I An AGN-driven outflow in the dense molecular gas
• Dust Emission from Active Galactic Nuclei
• Three-dimensional radiative transfer modeling of AGN dusty tori as a clumpy two-phase medium
• Bars and Warps traced by the Molecular Gas in the Seyfert 2 Galaxy NGC 1068
• Torus and AGN properties of nearby Seyfert galaxies: Results from fitting IR spectral energy distributions and spectroscopy
• Resolving the obscuring torus in NGC 1068 with the power of infrared interferometry: Revealing the inner funnel of dust
• The Parsec-scale Radio Structure of NGC 1068 and the Nature of the Nuclear Radio Source
• High Spatial Resolution Imaging of NGC 1068 in the Mid Infrared
• Deep Mid-Infrared Silicate Absorption as a Diagnostic of Obscuring Geometry Toward Galactic Nuclei
• The Nature of the Nuclear H2O Masers of NGC 1068: Reverberation and Evidence for a Rotating Disk Geometry
• Spatially-resolved mid-infrared spectroscopy of NGC 1068: the nature and distribution of the nuclear material
• Water maser emission and the parsec-scale jet in NGC 3079
• Gas and stellar dynamics in NGC 1068. Probing the galactic gravitational potential
• Revealing the large nuclear dust structures in NGC 1068 with MIDI/VLTI
• Resolved Spectra of the Narrow-Line Region in NGC 1068. III. Physical Conditions in the Emission-Line Gas
• Resolved Spectroscopy of the Narrow-Line Region in NGC 1068. II. Physical Conditions Near the NGC 1068 ``Hot-Spot''
• 2D mapping of young stars in the inner 180 pc of NGC 1068: correlation with molecular gas ring and stellar kinematics
• Extremely Rapid Variations of Water Maser Emission from the Circinus Galaxy
• Dynamics of the Narrow-Line Region in the Seyfert 2 Galaxy NGC 1068
• Gemini Imaging of Mid-IR Emission from the Nuclear Region of Centaurus A
• Mid Infrared Spectral Energy Distribution of NGC 1068 with 0.1 arcsec Spatial Resolution
• Gemini Mid-IR Polarimetry of NGC1068: Polarized Structures Around the Nucleus
• Resolved Spectroscopy of the Narrow-Line Region in NGC 1068. I. The Nature of the Continuum Emission
• Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind
• High Resolution Mid-Infrared Imaging of the Nucleus of NGC 1068
• HST NICMOS Observations of the Polarization of NGC 1068
• The 9.7 Micron Silicate Dust Absorption Toward the Cygnus A Nucleus and the Inferred Location of the Obscuring Dust
• Physical Conditions in the X-ray Emission-line Gas in NGC 1068
• The Location of the Nucleus and the Morphology of Emission-Line Regions in NGC 1068
• An original interferometric study of NGC 1068 with VISIR BURST mode images
• Analysis of the distribution of HII regions in external galaxies. IV The new galaxy sample. Position and Inclination angles
• Distribution of dust clouds around the central engine of NGC 1068
• Modeling the Infrared Extinction toward the Galactic Center
• Dichroic polarization at mid-infrared wavelengths: a Bayesian approach

Cited by in corpus (18)

• ALMA images the many faces of the NGC1068 torus and its surroundings
• The emission and distribution of dust of the torus of NGC 1068
• ALMA polarimetry measures magnetically aligned dust grains in the torus of NGC 1068
• AGN torus detectability at sub-millimeter wavelengths: What to expect from ALMA continuum data
• High-energy Neutrinos from the Inner Circumnuclear Region of NGC 1068
• SOFIA/HAWC+ traces the magnetic fields in NGC 1068
• A complete disclosure of the hidden type-1 AGN in NGC 1068 thanks to 52 years of broadband polarimetric observation
• The Magnetic Field in the central parsec of the Galaxy
• The origin of the mid-infrared nuclear polarization of active galactic nuclei
• A Compact Jet at the Infrared Heart of the Prototypical Low-Luminosity AGN in NGC 1052
• Hypercubes of AGN Tori (HYPERCAT) -- II. Resolving the Torus with Extremely Large Telescopes
• Infrared polarimetry of Mrk 231: Scattering off hot dust grains in the central core
• The mineralogy of newly formed dust in active galactic nuclei
• On the origin of radio-loudness in active galactic nuclei using far-infrared polarimetric observations
• The complex infrared dust continuum emission of NGC1068: ground-based N- and Q-band spectroscopy and new radiative transfer models
• Magneto Rotational Instability in Magnetized AGN Tori
• A Massive Dense Gas Cloud close to the Nucleus of the Seyfert galaxy NGC 1068
• High angular resolution polarimetric imaging of the nucleus of NGC 1068: Disentangling the polarising mechanisms