''Forbidden" stars in the eROSITA all-sky survey: X-ray emission from very late-type giants
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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866911971691986944 |
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| author | Schmitt, J. H. M. M. Hünsch, M. Schneider, P. C. Freund, S. Czesla, S. Robrade, J. Schwope, A. |
| author_facet | Schmitt, J. H. M. M. Hünsch, M. Schneider, P. C. Freund, S. Czesla, S. Robrade, J. Schwope, A. |
| contents | We present the results of the first X-ray all-sky survey (eRASS1) performed by the eROSITA instrument onboard the Spectrum-Roentgen-Gamma (SRG) mission on X-ray emitting red giants and supergiants. Focussing on stars positioned at high galactic latitudes above 20 deg, we construct a complete sample of such objects using the Gaia DR3 catalog and identify a sample 96 stars appearing as bona fide entries in the eRASS1 source catalog. Restricting again the sample to objects nearer than 1300~pc and eliminating all catalog entries which are due to optical contamination, we end up with a sample of 16 genuine red giant/supergiant X-ray sources, which represent -- with the exception of one source (CL~Hyi) -- new X-ray detections. We furthermore present a low SNR X-ray spectrum of the nearby low activity giant Arcturus obtained from a pointed observation with the XMM-Newton satellite and give a detailed account of our data analysis. We show that Arcturus-like X-ray emission cannot be the explanation for the X-ray emissions observed by eROSITA and provide a discussion of the possible nature of the detected X-ray sources. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2401_17273 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | ''Forbidden" stars in the eROSITA all-sky survey: X-ray emission from very late-type giants Schmitt, J. H. M. M. Hünsch, M. Schneider, P. C. Freund, S. Czesla, S. Robrade, J. Schwope, A. Solar and Stellar Astrophysics Astrophysics of Galaxies We present the results of the first X-ray all-sky survey (eRASS1) performed by the eROSITA instrument onboard the Spectrum-Roentgen-Gamma (SRG) mission on X-ray emitting red giants and supergiants. Focussing on stars positioned at high galactic latitudes above 20 deg, we construct a complete sample of such objects using the Gaia DR3 catalog and identify a sample 96 stars appearing as bona fide entries in the eRASS1 source catalog. Restricting again the sample to objects nearer than 1300~pc and eliminating all catalog entries which are due to optical contamination, we end up with a sample of 16 genuine red giant/supergiant X-ray sources, which represent -- with the exception of one source (CL~Hyi) -- new X-ray detections. We furthermore present a low SNR X-ray spectrum of the nearby low activity giant Arcturus obtained from a pointed observation with the XMM-Newton satellite and give a detailed account of our data analysis. We show that Arcturus-like X-ray emission cannot be the explanation for the X-ray emissions observed by eROSITA and provide a discussion of the possible nature of the detected X-ray sources. |
| title | ''Forbidden" stars in the eROSITA all-sky survey: X-ray emission from very late-type giants |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2401.17273 |