Distinct Jet Properties in the X-Ray-Obscured State of GRS 1915+105
astro-ph.HE
Submitted: 2026-07-30
Updated: 2026-08-28
Comments: This is a revised manuscript submitted to ApJ
License: http://creativecommons.org/licenses/by/4.0/
The gist: GRS 1915+105 has remained in an X-ray-obscured state since its transition from a long-lasting unobscured state in 2019.
Terminology
Abstract
GRS 1915+105 has remained in an X-ray-obscured state since its transition from a long-lasting unobscured state in 2019. We report on 6.7-GHz East Asia VLBI Network observations of GRS 1915+105 obtained during strong radio flares detected at 2.3--11.2 GHz with the RATAN-600 radio telescope in 2025. Our images reveal two contrasting jet morphologies. The first epoch, associated with a flare evolving from an optically thick to an optically thin spectrum, shows a bright radio core accompanied by an extended jet structure. By contrast, the second epoch, observed near the peak of another flare displaying optically thin emission at lower frequencies, is dominated by two bright, symmetric, well-separated jet blobs and shows no detectable radio core. If these jets exhibited the apparent superluminal motions commonly observed prior to 2019, measurable angular shifts would be expected over the five-hour observations. However, no significant jet motion is detected. Combined with our derived jet speed of beta 0.40, these results suggest that the jets launched during the current obscured state are slower than the relativistic jets (beta 1) observed earlier during the unobscured state. Together with the recently reported large variations in jet orientation, our findings in GRS 1915+105 provide robust support for the emerging paradigm that X-ray binary jets launched in obscured and unobscured states likely exhibit distinct propagation properties.
Sources
- An intrinsic decline of accretion activity in GRS 1915+105
- Accretion instabilities and jet formation in GRS 1915+105
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