Up and Down the Black Hole Radio/X-ray Correlation: the 2017 mini-outbursts from Swift J1753.5-0127

TL;DR

This study monitors the radio and X-ray emissions of Swift J1753.5-0127 during its 2017 mini-outbursts, revealing consistent behavior at low luminosities and providing insights into the jet-disk coupling in black hole X-ray binaries.

Contribution

It presents the first detailed radio/X-ray correlation analysis at very low luminosities during a black hole binary's outburst rise and decay, expanding understanding of jet and accretion physics.

Findings

Swift J1753.5-0127 follows a similar radio/X-ray correlation as other black hole binaries at low luminosities.

The system emitted less radio flux than expected during its prolonged outburst.

The study includes the lowest luminosity quasi-simultaneous radio/X-ray detection during outburst rise.

Abstract

The candidate black hole X-ray binary Swift J1753.5-0127 faded to quiescence in 2016 November, after a prolonged outburst that was discovered in 2005. Nearly three months later the system displayed renewed activity that lasted through 2017 July. Here, we present radio and X-ray monitoring over ~3 months of the renewed activity to study the coupling between the jet and the inner regions of the disk/jet system. Our observations cover low X-ray luminosities that have not historically been well-sampled (Lx~2e33 - 1e36 erg/s; 1-10 keV), including time periods when the system was both brightening and fading. At these low luminosities Swift J1753.5-0127 occupies a parameter space in the radio/X-ray luminosity plane that is comparable to "canonical" systems (e.g., GX 339-4), regardless of whether the system was brightening or fading, even though during its >11-year outburst Swift J1753.5-0127 emitted less radio emission from its jet than expected. We discuss implications for the existence of a single radio/X-ray luminosity correlation for black hole X-ray binaries at the lowest luminosities (Lx < 1e35 erg/s), and we compare to supermassive black holes. Our campaign includes the lowest luminosity quasi-simultaneous radio/X-ray detection to date for a black hole X-ray binary during its rise out of quiescence, thanks to early notification from optical monitoring combined with fast responses from sensitive multiwavelength facilities.