1. Infrared polarimetry of Mrk 231: scattering off hot dust grains in the central core.
- Author
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Lopez-Rodriguez, E., Packham, C., Jones, T. J., Siebenmorgen, R., Roche, P. F., Levenson, N. A., Alonso-Herrero, A., Perlman, E., Ichikawa, K., Almeida, C. Ramos, González-Martín, O., Nikutta, R., Martinez-Paredez, M., Shenoy, D., Gordon, M. S., and Telesco, C. M.
- Subjects
POLARIMETRY ,SPECTRUM analysis ,SPECTRAL energy distribution ,OPTICAL measurements ,OPTICAL polarization - Abstract
We present high-angular (0.17-0.35 arcsec) resolution imaging polarimetric observations of Mrk 231 in the 3.1 μm filter using MMT-Pol on the 6.5-m MMT, and in the 8.7, 10.3, and 11.6 μm filters using CanariCam on the 10.4-m Gran Telescopio CANARIAS. In combination with already published observations, we compile the 1-12 μm total and polarized nuclear spectral energy distribution (SED). The total flux SED in the central 400 pc is explained as the combination of (1) a hot (731 ± 4 K) dusty structure, directly irradiated by the central engine, which is at 1.6 ± 0.1 pc away and attributed to be in the pc-scale polar region, (2) an optically-thick, smooth and disc-like dusty structure ('torus') with an inclination of 48° ± 23° surrounding the central engine, and (3) an extinguished (AV = 36 ± 5 mag) starburst component. The polarized SED decreases from 0.77 ± 0.14 per cent at 1.2 μm to 0.31 ± 0.15 per cent at 11.6 μm and follows a power-law function, λ
~0.57 . The polarization angle remains constant (~108°) in the 1-12 μm wavelength range. The dominant polarization mechanism is explained as scattering-off hot dust grains in the pc-scale polar regions. [ABSTRACT FROM AUTHOR]- Published
- 2017
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