Distinct Jet Properties in the X-Ray-Obscured State of GRS 1915+105
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 βΓ≲ 0.40, these results suggest that the jets launched during the current obscured state are slower than the relativistic jets (βΓ≳ 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.
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BibTeX
@misc{yan2026distinct,
title = {{Distinct Jet Properties in the X-Ray-Obscured State of GRS 1915+105}},
author = {Xi Yan and Lang Cui and Sergei Trushkin and Shuangjing Xu and Wu Jiang and Zhen Yan and Sándor Frey and Timur Mufakharov and Ruchika Dhaka},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2607.27688},
eprint = {2607.27688},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.27688},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Distinct Jet Properties in the X-Ray-Obscured State of GRS 1915+105
AU - Xi Yan
AU - Lang Cui
AU - Sergei Trushkin
AU - Shuangjing Xu
AU - Wu Jiang
AU - Zhen Yan
AU - Sándor Frey
AU - Timur Mufakharov
AU - Ruchika Dhaka
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2607.27688
UR - https://arxiv.org/abs/2607.27688
AB - 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 βΓ≲ 0.40, these results suggest that the jets launched during the current obscured state are slower than the relativistic jets (βΓ≳ 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.
ER -