• DOI:10.1093/mnras/sty1322
• Corpus ID: 119097523

Morphology of AGN emission-line regions in SDSS-IV MaNGA survey

@article{He2018MorphologyOA,
  title={Morphology of AGN emission-line regions in SDSS-IV MaNGA survey},
  author={Zhicheng He and Ai-Lei Sun and Nadia L. Zakamska and Dominika Wylezalek and Michael Kelly and Jenny E. Greene and Sandro Barboza Rembold and Rog{\'e}rio Riffel and Rogemar A. Riffel},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2018},
  volume={478},
  pages={3614-3626}
}

• Zhicheng He, Ai-Lei Sun, +6 authors R. Riffel
• Published 17 May 2018
• Physics
• Monthly Notices of the Royal Astronomical Society

Extended narrow-line regions (NLRs) around active galactic nuclei (AGN) are shaped by the distribution of gas in the host galaxy and by the geometry of the circumnuclear obscuration, and thus they can be used to test the AGN unification model. In this work, we quantify the morphologies of the narrow-line regions in 308 nearby AGNs ($z=0-0.14$, \lbol $\sim 10^{42.4-44.1}$ \erg{}) from the MaNGA survey. Based on the narrow-line region maps, we find that a large fraction (81\%) of these AGN have bi-conical NLR morphology. The distribution of their measured opening angles suggests that the intrinsic opening angles of the ionization cones has a mean value of 85--98$^\circ$ with a finite spread of 39-44$^\circ$ (1-$\sigma$). Our inferred opening angle distribution implies a number ratio of type I to type II AGN of 1:1.6--2.3, consistent with other measurements of the type I / type II ratio at low AGN luminosities. Combining these measurements with the WISE photometry data, we find that redder mid-IR color (lower effective temperature of dust) corresponds to stronger and narrower photo-ionized bicones. This relation is in agreement with the unification model that suggests that the bi-conical narrow-line regions are shaped by a toroidal dusty structure within a few pc from the AGN. Furthermore, we find a significant alignment between the minor axis of host galaxy disks and AGN ionization cones. Together, these findings suggest that obscuration on both circumnuclear ($\sim $pc) and galactic ($\sim$ kpc) scales are important in shaping and orienting the AGN narrow-line regions.