Open AccessNear‐infrared imaging polarimetry and modelling of NGC 4151
Author(s) -
Ruiz M.,
Young S.,
Packham C.,
Alexander D. M.,
Hough J. H.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06239.x
Subject(s) - physics , position angle , polarimetry , torus , astrophysics , polarization (electrochemistry) , scattering , galaxy , line of sight , radius , conical surface , infrared , astronomy , optics , geometry , chemistry , mathematics , computer security , computer science
We present subarcsec resolution imaging polarimetry of the Seyfert 1 galaxy NGC 4151 in the J (1.23 μm) and H (1.64 μm) bands. The polarized flux images show elongated emission in both near‐infrared bands, mainly to the north‐east along a position angle of 30°. Detailed modelling indicates that the observed polarization can be reproduced by scattering in a very broad bi‐conical structure, and in the region of the disc of the host galaxy illuminated by the AGN. The forward scattering and illumination cone has a half‐opening angle of 60° and is at an inclination of 40° to the line of sight. To produce the best fit to the observations, an optically thick torus is required to attenuate the view to the bulk of the counter‐scattering cone in the north‐eastern direction. This torus has an outer radius of ≈15 pc, consistent with the constraints from radio observations.