Bibcode
Pierce, J. C. S.; Tadhunter, C. N.; Ramos Almeida, C.; Bessiere, P. S.; Rose, M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 4, p.5490-5507
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8
2019
Citations
20
Refereed citations
19
Description
Active galactic nuclei (AGNs) with intermediate radio powers are capable
of driving multiphase outflows in galaxy bulges, and are also more
common than their high-radio-power counterparts. In-depth
characterization of the typical host galaxies and likely triggering
mechanisms for this population is therefore required in order to better
understand the role of radio AGN feedback in galaxy evolution. Here, we
use deep optical imaging data to study the detailed host morphologies of
a complete sample of 30 local radio AGNs with high-excitation optical
emission (HERG) spectra and intermediate radio powers [ z < 0.1; 22.5
< log(L_1.4GHz) < 24.0 W Hz-1]. The fraction of hosts
with morphological signatures of mergers and interactions is greatly
reduced compared to the 2Jy radio-powerful galaxies [log(L_1.4GHz) >
25.0 W Hz-1] with strong optical emission lines: 53 ±
9 per cent compared with 94 ± 4 per cent. In addition, the most
radio-powerful half of the sample has a higher frequency of
morphological disturbance than the least radio-powerful half (67
± 12 per cent and 40 ± 13 per cent, respectively),
including the eight most highly disturbed galaxies. This suggests that
the importance of triggering nuclear activity in high-excitation radio
galaxies (HERGs) through mergers and interactions reduces with radio
power. Both visual inspection and detailed light profile modelling
reveal a mixed population of early-type and late-type morphologies,
contrary to the massive elliptical galaxy hosts of radio-powerful AGNs.
The prevalence of late-type hosts could suggest that triggering via
secular, disc-based processes has increased importance for HERGs with
lower radio powers (e.g. disc instabilities and large-scale bars).
Related projects
Nuclear Activity in Galaxies: a 3D Perspective from the Nucleus to the Outskirts
This project consists of two main research lines. First, the study of quasar-driven outflows in luminous and nearby obscured active galactic nuclei (AGN) and the impact that they have on their massive host galaxies (AGN feedback). To do so, we have obtained Gran Telescopio CANARIAS (GTC) infrared and optical observations with the instruments
Cristina
Ramos Almeida