# The Role of Major Mergers and Nuclear Star Formation in Nearby Obscured Quasars

## TL;DR

This study examines the structural features and triggering mechanisms of nearby obscured quasars, revealing that most host galaxies are disk-dominated with prevalent nuclear star formation, and only a minority are involved in mergers.

## Contribution

It provides detailed morphological analysis of type 2 quasar hosts, highlighting the dominance of disk galaxies and the role of bars and nuclear star formation in fueling activity.

## Key findings

- Majority of hosts are disk-dominated late-type galaxies.
- Few hosts are involved in mergers or interactions.
- Nuclear star formation is common, affecting galaxy color and brightness.

## Abstract

We investigate the triggering mechanism and the structural properties of obscured luminous active galactic nuclei from a detailed study of the rest-frame $B$ and $I$ HST images of 29 nearby ($z\approx 0.04-0.4$) optically selected type 2 quasars. Morphological classification reveals that only a minority (34%) of the hosts are mergers or interacting galaxies. More than half (55%) of the hosts contain regular disks, and a substantial fraction (38%), in fact, are disk-dominated ($B/T\lesssim 0.2$) late-type galaxies with low Sersic indices ($n < 2$), which is characteristic of pseudo bulges. The prevalence of bars in the spiral host galaxies may be sufficient to supply the modest fuel requirements needed to power the nuclear activity in these systems. Nuclear star formation seems to be ubiquitous in the central regions, leading to positive color gradients within the bulges and enhancements in the central surface brightness of most systems.