dorsal/arxiv
View SchemaDirect detection of the non-thermal X-ray emission from the Arches star cluster
| Authors | Roman Krivonos, Alexey Vikhlinin, Andrei Bykov, Sergey Sazonov, Maïca Clavel |
|---|---|
| Categories | |
| ArXiv ID | 2601.07357vv1 |
| URL | https://arxiv.org/abs/2601.07357 |
| License | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
Abstract
The compact stellar clusters have emerged as particularly promising candidates for cosmic rays (CR) accelerators. The star clusters, recently observed in gamma-rays, are also known sources of non-thermal X-ray emission, which is due to synchrotron or inverse-Compton scattering of relativistic electrons. Thus, the search for the non-thermal X-ray emission from stellar clusters is of particular interest. Until recent time the X-ray emission of the Arches star cluster in the Galactic Center was mixed with non-thermal emission of the surrounding molecular cloud, associated with reflection of hard X-ray irradiation. This reflected emission has been observed to fade, giving us a chance to characterize intrinsic non-thermal emission of the Arches cluster. In this work we demonstrate that Fe K_alpha line emission at 6.4 keV, attributed to the reflected non-thermal emission of the molecular cloud in 2000-2010, is not detected in deep observations with XMM-Newton in 2020 and Chandra in 2022, leaving stellar cluster well isolated. We showed that the Arches non-thermal emission is localized in the cluster's core and characterized by a relatively weak, hard (Gamma~1.5) power-law spectral continuum with 2-10 keV flux of ~10E-13 ergs/s/cm^2.
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"abstract": "The compact stellar clusters have emerged as particularly promising candidates for cosmic rays (CR) accelerators. The star clusters, recently observed in gamma-rays, are also known sources of non-thermal X-ray emission, which is due to synchrotron or inverse-Compton scattering of relativistic electrons. Thus, the search for the non-thermal X-ray emission from stellar clusters is of particular interest. Until recent time the X-ray emission of the Arches star cluster in the Galactic Center was mixed with non-thermal emission of the surrounding molecular cloud, associated with reflection of hard X-ray irradiation. This reflected emission has been observed to fade, giving us a chance to characterize intrinsic non-thermal emission of the Arches cluster. In this work we demonstrate that Fe K_alpha line emission at 6.4 keV, attributed to the reflected non-thermal emission of the molecular cloud in 2000-2010, is not detected in deep observations with XMM-Newton in 2020 and Chandra in 2022, leaving stellar cluster well isolated. We showed that the Arches non-thermal emission is localized in the cluster\u0027s core and characterized by a relatively weak, hard (Gamma~1.5) power-law spectral continuum with 2-10 keV flux of ~10E-13 ergs/s/cm^2.",
"arxiv_id": "2601.07357",
"authors": [
"Roman Krivonos",
"Alexey Vikhlinin",
"Andrei Bykov",
"Sergey Sazonov",
"Ma\u00efca Clavel"
],
"categories": [
"astro-ph.HE"
],
"license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
"title": "Direct detection of the non-thermal X-ray emission from the Arches star cluster",
"url": "https://arxiv.org/abs/2601.07357",
"version": "v1"
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