We investigate the possible link between mergers and the enhanced activity of supermassive black holes (SMBHs) at the centre of galaxies, by comparing the merger fraction of a local sample (0.003 ≤ z < 0.03) of active galaxies - 59 active galactic nuclei host galaxies selected from the All-Sky Swift Burst Alert Telescope (BAT) Survey - with an appropriate control sample (247 sources extracted from the HyperLeda catalogue) that has the same redshift distribution as the BAT sample. We detect the interacting systems in the two samples on the basis of non-parametric structural indexes of concentration (C), asymmetry (A), clumpiness (S), Gini coefficient (G) and second-order momentum of light (M20). In particular, we propose a new morphological criterion, based on a combination of all these indexes, that improves the identification of interacting systems. We also present a new software - PyCASSo (PYTHON CAS software) - for the automatic computation of the structural indexes. After correcting for the completeness and reliability of the method, we find that the fraction of interacting galaxies among the active population (20{^{+ 7}_{- 5}} per cent) exceeds the merger fraction of the control sample (4{^{+ 1.7}_{- 1.2}} per cent). Choosing a mass-matched control sample leads to equivalent results, although with slightly lower statistical significance. Our findings support the scenario in which mergers trigger the nuclear activity of SMBHs.

Cotini, S., Ripamonti, E., Caccianiga, A., Colpi, M., Della Ceca, R., Mapelli, M., et al. (2013). The merger fraction of active and inactive galaxies in the local Universe through an improved non-parametric classification. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 431(3), 2661-2672 [10.1093/mnras/stt358].

The merger fraction of active and inactive galaxies in the local Universe through an improved non-parametric classification

COLPI, MONICA;
2013

Abstract

We investigate the possible link between mergers and the enhanced activity of supermassive black holes (SMBHs) at the centre of galaxies, by comparing the merger fraction of a local sample (0.003 ≤ z < 0.03) of active galaxies - 59 active galactic nuclei host galaxies selected from the All-Sky Swift Burst Alert Telescope (BAT) Survey - with an appropriate control sample (247 sources extracted from the HyperLeda catalogue) that has the same redshift distribution as the BAT sample. We detect the interacting systems in the two samples on the basis of non-parametric structural indexes of concentration (C), asymmetry (A), clumpiness (S), Gini coefficient (G) and second-order momentum of light (M20). In particular, we propose a new morphological criterion, based on a combination of all these indexes, that improves the identification of interacting systems. We also present a new software - PyCASSo (PYTHON CAS software) - for the automatic computation of the structural indexes. After correcting for the completeness and reliability of the method, we find that the fraction of interacting galaxies among the active population (20{^{+ 7}_{- 5}} per cent) exceeds the merger fraction of the control sample (4{^{+ 1.7}_{- 1.2}} per cent). Choosing a mass-matched control sample leads to equivalent results, although with slightly lower statistical significance. Our findings support the scenario in which mergers trigger the nuclear activity of SMBHs.
Articolo in rivista - Articolo scientifico
galaxies: active, galaxies: interactions
English
2013
431
3
2661
2672
open
Cotini, S., Ripamonti, E., Caccianiga, A., Colpi, M., Della Ceca, R., Mapelli, M., et al. (2013). The merger fraction of active and inactive galaxies in the local Universe through an improved non-parametric classification. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 431(3), 2661-2672 [10.1093/mnras/stt358].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/50946
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