Unusual Double-peaked Emission in the SDSS Quasar J093201.60+031858.7

TL;DR

This paper analyzes the spectral features of the SDSS quasar J093201.60+031858.7, highlighting its unique double-peaked emission lines and exploring whether these features indicate a single complex accretion disk or a binary supermassive black hole system.

Contribution

It presents a detailed spectral analysis of an unusual double-peaked quasar and evaluates models for its emission lines, including the binary SMBH hypothesis, to distinguish between different physical scenarios.

Findings

The quasar exhibits unique, sharp blue peaks in Balmer lines.

Disk modeling suggests asymmetry is needed to explain the blue peak.

Comparison with binary SMBH models provides insights into the emission features.

Abstract

We examine spectral properties of the SDSS quasar J093201.60+031858.7, in particular the presence of strong blue peaks in the Balmer emission lines offset from the narrow lines by approximately 4200 km/s. Asymmetry in the broad central component of the Hbeta line indicates the presence of a double-peaked emitter. However, the strength and sharpness of the blue Hbeta and blue Hgamma peaks make this quasar spectrum unique amongst double-peaked emitters identified from SDSS spectra. We fit a disk model to the Hbeta line and compare this object with other unusual double-peaked quasar spectra, particularly candidate binary supermassive black holes (SMBHs). Under the binary SMBH scenario, we test the applicability of a model in which a second SMBH may produce the strong blue peak in the Balmer lines of a double-peaked emitter. If there were only one SMBH, a circular, Keplerian disk model fit would be insufficient, indicating some sort of asymmetry is required to produce the strength of the blue peak. In either case, understanding the nature of the complex line emission in this object will aid in further discrimination between a single SMBH with a complex accretion disk and the actual case of a binary SMBH.