Evidence of bar--driven secular evolution in the gamma--ray narrow--line Seyfert 1 galaxy FBQS J164442.5+261913

TL;DR

This study provides the first detailed morphological analysis of the gamma-ray emitting Narrow Line Seyfert 1 galaxy FBQS J164442.5+261913, revealing a barred lenticular host galaxy with a pseudo-bulge and evidence of secular evolution driven by the bar and minor mergers.

Contribution

It is the first morphological study of this gamma-ray NLSy1 galaxy, showing a barred SB0 host with a pseudo-bulge and ring, highlighting secular evolution's role in nuclear activity.

Findings

Host galaxy is a barred lenticular (SB0) with a pseudo-bulge.

Presence of a ring likely caused by bar-driven gas rearrangement and minor mergers.

Bar-driven secular evolution influences nuclear activity and bulge growth.

Abstract

We present near--infrared (NIR) imaging of FBQS J164442.5+261913, one of the few $\gamma$--ray emitting Narrow Line Seyfert 1 ($\gamma-$NLSy1) galaxies detected at high significance level by $Fermi$--LAT. This study is the first morphological analysis performed of this source and the third performed of this class of objects. Conducting a detailed two--dimensional modeling of its surface brightness distribution and analysing its $J-K_s$ colour gradients, we find that FBQS J164442.5+261913 is statistically most likely hosted by a barred lenticular galaxy (SB0). We find evidence that the bulge in the host galaxy of FBQS J164442.5+261913 is not classical but pseudo, against the paradigm of powerful relativistic jets exclusively launched by giant ellipticals. Our analysis, also reveal the presence of a ring with diameter equalling the bar length ($r_{bar} = 8.13\ \textrm{kpc}\pm 0.25$), whose origin might be a combination of bar--driven gas rearrangement and minor mergers, as revealed by the apparent merger remnant in the $J$--band image. In general, our results suggest that the prominent bar in the host galaxy of FBQS J164442.5+261913 has mostly contributed to its overall morphology driving a strong secular evolution, which plays a crucial role in the onset of the nuclear activity and the growth of the massive bulge. Minor mergers, in conjunction, are likely to provide the necessary fresh supply of gas to the central regions of the host galaxy.