A decade of high-resolution radio observations of GRS 1915+105

TL;DR

This paper presents a decade of high-resolution radio observations of GRS 1915+105, revealing jet ejections, polarization properties, and evidence for jet precession in this X-ray binary system.

Contribution

It provides the first spatially resolved polarization measurements of the jets and links jet ejections to X-ray flaring over a ten-year period.

Findings

Polarization has been spatially resolved in the jets.

Jet ejections are associated with X-ray flares.

Proper motions suggest jet precession.

Abstract

The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We present a decade of monitoring observations, with the RXTE-ASM and the Ryle Telescope, in conjunction with high-resolution radio observations using MERLIN and the VLBA. Linear polarisation at 1.4 and 1.6 GHz has been spatially resolved in the radio jets, on a scale of ~150 mas and at flux densities of a few mJy. Depolarisation of the core occurs during radio flaring, associated with the ejection of relativistic knots of emission. We have identified the ejection at four epochs of X-ray flaring. Assuming no deceleration, proper motions of 16.5 to 27 mas per day have been observed, supporting the hypothesis of a varying angle to the line-of-sight per ejection, perhaps in a precessing jet.