X-ray counterparts to stellar MeerKAT Galactic-plane compact radio sources
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arXiv
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| Auteurs principaux: | , , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866910008751423488 |
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| author | Egbo, O. D. Groot, P. J. Buckley, D. A. H. Robrade, J. Schwope, A. D. Freund, S. Schneider, P. C. Stelzer, B. |
| author_facet | Egbo, O. D. Groot, P. J. Buckley, D. A. H. Robrade, J. Schwope, A. D. Freund, S. Schneider, P. C. Stelzer, B. |
| contents | Radio emission from magnetically active stars arises mainly from non-thermal processes and complements high-energy X-ray emission. Sensitive, wide-field radio and X-ray surveys now allow identification of larger samples of active stars across the Galaxy. We aim to identify and characterise radio and X-ray-emitting stars in the Galactic plane by combining MeerKAT radio data with soft X-ray observations and assess their consistency with the canonical Güdel-Benz relation, which links thermal coronal X-rays to non-thermal gyrosynchrotron radio emission. We cross-matched compact sources from the SARAO MeerKAT Galactic Plane Survey with counterparts from the ROSAT All-Sky Survey and the first release of SRG/eROSITA (eRASS1). We computed radio-brightness temperatures and radio-X-ray luminosities to test the relation. We identify 137 stars with both radio and X-ray detections. Their $T_B$ ranges from $10^7$ to $10^{12}$ K, except two outliers: AXJ1600.9-5142 ($4.8 \pm 1.5 \times 10^{12}$ K) and HD~124831 ($8 \pm 1 \times 10^{6}$ K). The remainder are consistent with incoherent gyrosynchrotron emission. The sample lies below the canonical Güdel-Benz relation, driven by enhanced 1.3 GHz radio luminosities relative to the 5 GHz relation. This suggests the classical relation represents an upper envelope rather than a tight correlation. Additionally, eROSITA detections show early-type stars lie below the typical $\log (L_{\rm X}/L_{\rm bol}) \sim -3$ relation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2602_02054 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | X-ray counterparts to stellar MeerKAT Galactic-plane compact radio sources Egbo, O. D. Groot, P. J. Buckley, D. A. H. Robrade, J. Schwope, A. D. Freund, S. Schneider, P. C. Stelzer, B. Solar and Stellar Astrophysics Astrophysics of Galaxies High Energy Astrophysical Phenomena Radio emission from magnetically active stars arises mainly from non-thermal processes and complements high-energy X-ray emission. Sensitive, wide-field radio and X-ray surveys now allow identification of larger samples of active stars across the Galaxy. We aim to identify and characterise radio and X-ray-emitting stars in the Galactic plane by combining MeerKAT radio data with soft X-ray observations and assess their consistency with the canonical Güdel-Benz relation, which links thermal coronal X-rays to non-thermal gyrosynchrotron radio emission. We cross-matched compact sources from the SARAO MeerKAT Galactic Plane Survey with counterparts from the ROSAT All-Sky Survey and the first release of SRG/eROSITA (eRASS1). We computed radio-brightness temperatures and radio-X-ray luminosities to test the relation. We identify 137 stars with both radio and X-ray detections. Their $T_B$ ranges from $10^7$ to $10^{12}$ K, except two outliers: AXJ1600.9-5142 ($4.8 \pm 1.5 \times 10^{12}$ K) and HD~124831 ($8 \pm 1 \times 10^{6}$ K). The remainder are consistent with incoherent gyrosynchrotron emission. The sample lies below the canonical Güdel-Benz relation, driven by enhanced 1.3 GHz radio luminosities relative to the 5 GHz relation. This suggests the classical relation represents an upper envelope rather than a tight correlation. Additionally, eROSITA detections show early-type stars lie below the typical $\log (L_{\rm X}/L_{\rm bol}) \sim -3$ relation. |
| title | X-ray counterparts to stellar MeerKAT Galactic-plane compact radio sources |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2602.02054 |