The Twisted Radio Structure of PSO J334.2028+01.4075, Still a Supermassive Binary Black Hole Candidate

Abstract

Supermassive binary black holes (BBHs) on sub-parsec scales are prime targets for gravitational wave experiments. They also provide insights on close binary evolution and hierarchical structure formation. Sub-parsec BBHs cannot be spatially resolved but indirect methods can identify candidates. In 2015 Liu et al. reported an optical-continuum periodicity in the quasar PSO J334.2028+01.4075, with the estimated mass and rest-frame period suggesting an orbital separation of about 0.006 pc (0.7 micro-arcsec). The persistence of the quasar's optical periodicity has recently been disfavored over an extended baseline. However, if a radio jet is launched from a sub-parsec BBH, the binary's properties can influence the radio structure on larger scales. Here, we use the Very Long Baseline Array (VLBA) and Karl G. Jansky Very Large Array (VLA) to study the parsec- and kiloparsec-scale emission energized by the quasar's putative BBH. We find two VLBA components separated by 3.6 mas (30 pc), tentatively identifying one as the VLBA "core" from which the other was ejected. The VLBA components contribute to a point-like, time-variable VLA source that is straddled by lobes spanning 8 arcsec (66 kpc). We classify PSO J334.2028+01.4075 as a lobe-dominated quasar, albeit with an atypically large twist of 39 deg between its elongation position angles on parsec- and kiloparsec-scales. By analogy with 3C 207, a well-studied lobe-dominated quasar with a similarly-rare twist, we speculate that PSO J334.2028+01.4075 could be ejecting jet components over an inner cone that traces a precessing jet in a BBH system.

6 pages, 3 figures, 3 tables. Accepted for publication in MNRAS

References in corpus (8)

• A possible close supermassive black-hole binary in a quasar with optical periodicity
• Massive binary black holes in galactic nuclei and their path to coalescence
• A close-pair binary in a distant triple supermassive black-hole system
• A Periodically Varying Luminous Quasar at z=2 from the Pan-STARRS1 Medium Deep Survey: A Candidate Supermassive Black Hole Binary in the Gravitational Wave-Driven Regime
• A Systematic Search for Periodically Varying Quasars in Pan-STARRS1: An Extended Baseline Test in Medium Deep Survey Field MD09
• Radio-Selected Binary Active Galactic Nuclei from the Very Large Array Stripe 82 Survey
• Parsec-scale jet properties of the quasar PG 1302$-$102
• Detection of quasars in the time domain

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• From binary to singular: the AGN PSO J334.2028+1.4075 under the high-resolution scope
• Revisiting a Core-Jet Laboratory at High Redshift: Analysis of the Radio Jet in the Quasar PKS 2215+020 at z=3.572
• The rise and fall of a binary AGN candidate: the story of PSO J334.2028+1.4075
• Radio Jet Properties of the Flaring Gamma-Ray Blazar PKS 0346-27