The quasar SDSS J142507.32+323137.4 : dual AGNs?

TL;DR

This study analyzes the optical spectrum of quasar SDSS J1425+3231, revealing double-peaked emission lines that suggest it may host dual active galactic nuclei, with implications for understanding galaxy mergers and black hole interactions.

Contribution

It provides evidence for a potential dual AGN system based on spectral line analysis, a novel interpretation for this particular quasar.

Findings

Double-peaked narrow emission lines with ~500 km/s separation.

Black hole mass estimated at 0.85 x 10^8 solar masses.

Possible dual AGN system with obscured secondary black hole.

Abstract

We analyze the optical spectrum of type 1 QSO SDSS J1425+3231. This ob- ject is interesting since its narrow emission lines such as [O III]{\lambda}{\lambda}4959, 5007 are double- peaked, and the line structure can be modeled well by three Gaussian components: two components for the two peaks (we refer the peaks at low/high redshift as "the blue/red component") and another one for the line wing which has the same line center as that of the blue component, but ~ 3 times broader. The separation between the blue and red components is ~ 500 km/s with blue component ~ 2 times broader than the red one. The H{\beta} emission can be separated into four components: two for the double-peaked narrow line and two for the broad line which comes from the broad line region (BLRs). The black hole mass estimated from the broad H{\beta} emission line using the typical reverberation map- ping relation is 0.85 \times 108M\odot, which is consistent with that derived from parameters of [O III]{\lambda} 5007 of the blue component. We suggest this QSO might be a dual AGN system, the broad H{\beta} emission line is mainly contributed by the primary black hole (traced by the blue component) while the broad H{\beta} component of the secondary black hole (traced by the red component) is hard to be separated out considering a resolution of ~2000 of SDSS spectra or it is totally obscured by the dusty torus.