Issue |
A&A
Volume 596, December 2016
|
|
---|---|---|
Article Number | A20 | |
Number of page(s) | 8 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/201628752 | |
Published online | 23 November 2016 |
Data-driven dissection of emission-line regions in Seyfert galaxies
Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
e-mail: beatriz.villarroel@physics.uu.se; andreas.korn@physics.uu.se
Received: 20 April 2016
Accepted: 25 August 2016
Aims. Indirectly resolving the line-emitting gas regions in distant active galactic nuclei (AGN) requires both high-resolution photometry and spectroscopy (i.e. through reverberation mapping). Emission in AGN originates on widely different scales; the broad-line region (BLR) has a typical radius less than a few parsec, the narrow-line region (NLR) extends out to hundreds of parsecs. But emission also appears on large scales from heated nebulae in the host galaxies (tenths of kpc).
Methods. We propose a novel, data-driven method based on correlations between emission-line fluxes to identify which of the emission lines are produced in the same kind of emission-line regions. We tested the method on Seyfert galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) and Galaxy Zoo project.
Results. We demonstrate the usefulness of the method on Seyfert-1s and Seyfert-2 objects, showing similar narrow-line regions (NLRs). Preliminary results from comparing Seyfert-2s in spiral and elliptical galaxy hosts suggest that the presence of particular emission lines in the NLR depends both on host morphology and eventual radio-loudness. Finally, we explore an apparent linear relation between the final correlation coefficient obtained from the method and time lags as measured in reverberation mapping for Zw229-015.
Key words: methods: statistical / galaxies: active / galaxies: nuclei / galaxies: Seyfert / quasars: emission lines / surveys
© ESO, 2016
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