Bibcode
Bessiere, P. S.; Tadhunter, C. N.; Ramos Almeida, C.; Villar Martín, M.; Cabrera-Lavers, A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 466, Issue 4, p.3887-3917
Advertised on:
5
2017
Citations
16
Refereed citations
14
Description
Despite the emerging morphological evidence that luminous quasar-like
active galactic nuclei (AGN) are triggered in galaxy mergers, the
natures of the triggering mergers and the order of events in the
triggering sequence remain uncertain. In this work, we present a
detailed study of the stellar populations of the host galaxies of 21
type II quasars, with the aim of understanding the sequence of events
between the onset of the merger, the triggering of the associated
starburst and the initiation of the quasar activity. To this end, we
model high-quality, wide spectral coverage, intermediate-resolution
optical spectra of the type II quasars. We find that of the 21 objects,
the higher order Balmer absorption lines, characteristic of young
stellar populations (YSPs), are directly detected in ˜62 per cent
of the sample. We also fit these spectra using a number of combinations
of stellar and/or power-law components, representative of viable
formation histories, as well as including the possibility of scattered
AGN light. We find that ˜90 per cent of the type II quasar host
galaxies require the inclusion of a YSP to adequately model their
spectra, whilst 71 per cent of the sample require the inclusion of a YSP
with age <100 Myr. Since the ages of the YSP in most type II quasar
host galaxies are comparable with the expected lifetimes of the AGN
activity, these results provide strong evidence that the quasars are
triggered close to the peaks of the merger-induced starbursts.
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