Milliarcsecond-scale jet reorientations in GRS 1915+105 pointing towards a warped accretion disc
Abstract
The black hole X-ray binary GRS 1915+105 was persistently X-ray bright for over 26 years before entering a prolonged low X-ray flux state in 2018, while remaining bright at radio wavelengths. Multi-wavelength observations suggest this state results from a complex layer of absorbing material of unknown nature. Radio jet observations provide an unobstructed view of the physical changes during this phase, and recent Very Large Array and East Asian VLBI Network observations revealed substantial changes in the jet position angle (PA). We use higher-resolution VLBI observations to investigate the connection between the obscuration event and the jet behaviour close to the launch region. We observed GRS 1915+105 with the Very Long Baseline Array and European VLBI Network at four epochs during the early obscuration phase (2019-2021), sampling a diverse range of jet and accretion behaviours. We study the milliarcsecond jet morphology and PA changes and relate these to the reported X-ray behaviour. Many post-2018 PAs are significantly offset from the pre-obscuration jet axis, which has a weighted mean of 142∘ ± 7∘ on milliarcsecond scales. We measure a maximum offset of 57∘ ± 8∘, the largest reported for GRS 1915+105 to date. Our epochs reveal a variety of jet behaviour, ranging from a stable, compact source with a large PA offset, to a bright, flaring source with a similar offset, to an extended jet with a PA closer to the pre-obscuration axis, and a non-detection. The lack of measurable PA changes within individual 8-hour epochs rules out rapid Lense-Thirring precession of the inner disc as the direct driver of the jet reorientation. Instead, the timescales involved, the system geometry, and the apparent connection to the X-ray obscuration favour a radiation-driven warped accretion disc, a configuration that could naturally explain the persistent obscuration.
Related
- Semi-Analytic Solutions For Warped, Super-Eddington Accretion Disks with Outflows
- Observational signatures of warped accretion flows in tidal disruption events
- Quasi-periodic eruption spectral-timing: EMRIs crossing warped accretion disks
- Disc breaking and parametric instability in warped accretion discs driven by differential precession
- BlackHoleWeather – Spin-coupled chaotic cold accretion across the meso scale: Kinematics and variability
BibTeX
@misc{regt2026milliarcsecondscale,
title = {{Milliarcsecond-scale jet reorientations in GRS 1915+105 pointing towards a warped accretion disc}},
author = {L. I. de Regt and P. Atri and S. E. Motta and R. P. Fender and J. C. A. Miller-Jones and D. R. A. Williams-Baldwin},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.03395},
eprint = {2611.03395},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.03395},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Milliarcsecond-scale jet reorientations in GRS 1915+105 pointing towards a warped accretion disc
AU - L. I. de Regt
AU - P. Atri
AU - S. E. Motta
AU - R. P. Fender
AU - J. C. A. Miller-Jones
AU - D. R. A. Williams-Baldwin
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2611.03395
UR - https://arxiv.org/abs/2611.03395
AB - The black hole X-ray binary GRS 1915+105 was persistently X-ray bright for over 26 years before entering a prolonged low X-ray flux state in 2018, while remaining bright at radio wavelengths. Multi-wavelength observations suggest this state results from a complex layer of absorbing material of unknown nature. Radio jet observations provide an unobstructed view of the physical changes during this phase, and recent Very Large Array and East Asian VLBI Network observations revealed substantial changes in the jet position angle (PA). We use higher-resolution VLBI observations to investigate the connection between the obscuration event and the jet behaviour close to the launch region. We observed GRS 1915+105 with the Very Long Baseline Array and European VLBI Network at four epochs during the early obscuration phase (2019-2021), sampling a diverse range of jet and accretion behaviours. We study the milliarcsecond jet morphology and PA changes and relate these to the reported X-ray behaviour. Many post-2018 PAs are significantly offset from the pre-obscuration jet axis, which has a weighted mean of 142^∘ ± 7^∘ on milliarcsecond scales. We measure a maximum offset of 57^∘ ± 8^∘, the largest reported for GRS 1915+105 to date. Our epochs reveal a variety of jet behaviour, ranging from a stable, compact source with a large PA offset, to a bright, flaring source with a similar offset, to an extended jet with a PA closer to the pre-obscuration axis, and a non-detection. The lack of measurable PA changes within individual 8-hour epochs rules out rapid Lense-Thirring precession of the inner disc as the direct driver of the jet reorientation. Instead, the timescales involved, the system geometry, and the apparent connection to the X-ray obscuration favour a radiation-driven warped accretion disc, a configuration that could naturally explain the persistent obscuration.
ER -