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Constraining the nature of the most extreme Galactic particle accelerator. H.E.S.S. observations of the microquasar V4641 Sgr

Fuente: arXiv

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Autori principali:	Acharyya, A., Aharonian, F., Ashkar, H., Backes, M., Batzofin, R., Berge, D., Bernlöhr, K., Böttcher, M., Boisson, C., Bolmont, J., Brun, F., Bruno, B., Burger-Scheidlin, C., Bylund, T., Casanova, S., Celic, J., Cerruti, M., Chen, A., Chernyakova, M., Chibueze, J. O., Chibueze, O., Cornejo, B., Cotter, G., Scarpin, J. de Assis, de Lavergne, M. de Bony, de Naurois, M., Wilhelmi, E. de Oña, Giler, A. G. Delgado, Devin, J., Djannati-Ataï, A., Dmytriiev, A., Egberts, K., Egg, K., Ernenwein, J. -P., Nieves, C. Escañuela, Fauverge, P., Feijen, K., Filipovic, M. D., Fontaine, G., Funk, S., Gabici, S., Gallant, Y. A., Glicenstein, J. F., Glombitza, J., Goswami, P., Grondin, M. -H., Heckmann, L., Heß, B., Hinton, J. A., Hofmann, W., Holch, T. L., Holler, M., Jamrozy, M., Jankowsky, F., Jardin-Blicq, A., Jaroschewski, I., Jimeno, D., Jung-Richardt, I., Katarzyński, K., Kerszberg, D., Khélifi, B., Komin, N., Kosack, K., Kostunin, D., Lang, R. G., Lazarević, S., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Liniewicz, P., Luashvili, A., Mackey, J., Malyshev, D., Marandon, V., Mayer, M. G. F., Mehta, A., Mitchell, A. M. W., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Niemiec, J., Olivera-Nieto, L., Moghadam, M. O., Panny, S., Parsons, R. D., Pensec, U., Pichard, P., Preis, T., Pühlhofer, G., Punch, M., Quirrenbach, A., Reimer, A., Reimer, O., Reis, I., Remy, Q., Ren, H. X., Reville, B., Rieger, F., Roellinghoff, G., Rowell, G., Rudak, B., Sabri, K., Safi-Harb, S., Sahakian, V., Santangelo, A., Sasaki, M., Schüssler, F., Shapopi, J. N. S., Said, W. Si, Sol, H., Stawarz, Ł., Steinmassl, S., Tanaka, T., Taylor, A. M., Taylor, G. L., Terrier, R., Tian, Y., Timmermans, A., Tsirou, M., Tsuji, N., Unbehaun, T., van Eldik, C., Vecchi, M., Venter, C., Vink, J., Voitsekhovskyi, V., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., Zhong, W., Takekawa, S.
Natura:	Preprint
Pubblicazione:	2025
Soggetti:	High Energy Astrophysical Phenomena
Accesso online:	Acceder al recurso
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_version_	1866915615888900096
author	Acharyya, A. Aharonian, F. Ashkar, H. Backes, M. Batzofin, R. Berge, D. Bernlöhr, K. Böttcher, M. Boisson, C. Bolmont, J. Brun, F. Bruno, B. Burger-Scheidlin, C. Bylund, T. Casanova, S. Celic, J. Cerruti, M. Chen, A. Chernyakova, M. Chibueze, J. O. Chibueze, O. Cornejo, B. Cotter, G. Scarpin, J. de Assis de Lavergne, M. de Bony de Naurois, M. Wilhelmi, E. de Oña Giler, A. G. Delgado Devin, J. Djannati-Ataï, A. Dmytriiev, A. Egberts, K. Egg, K. Ernenwein, J. -P. Nieves, C. Escañuela Fauverge, P. Feijen, K. Filipovic, M. D. Fontaine, G. Funk, S. Gabici, S. Gallant, Y. A. Glicenstein, J. F. Glombitza, J. Goswami, P. Grondin, M. -H. Heckmann, L. Heß, B. Hinton, J. A. Hofmann, W. Holch, T. L. Holler, M. Jamrozy, M. Jankowsky, F. Jardin-Blicq, A. Jaroschewski, I. Jimeno, D. Jung-Richardt, I. Katarzyński, K. Kerszberg, D. Khélifi, B. Komin, N. Kosack, K. Kostunin, D. Lang, R. G. Lazarević, S. Lemière, A. Lemoine-Goumard, M. Lenain, J. -P. Liniewicz, P. Luashvili, A. Mackey, J. Malyshev, D. Marandon, V. Mayer, M. G. F. Mehta, A. Mitchell, A. M. W. Moderski, R. Mohrmann, L. Montanari, A. Moulin, E. Niemiec, J. Olivera-Nieto, L. Moghadam, M. O. Panny, S. Parsons, R. D. Pensec, U. Pichard, P. Preis, T. Pühlhofer, G. Punch, M. Quirrenbach, A. Reimer, A. Reimer, O. Reis, I. Remy, Q. Ren, H. X. Reville, B. Rieger, F. Roellinghoff, G. Rowell, G. Rudak, B. Sabri, K. Safi-Harb, S. Sahakian, V. Santangelo, A. Sasaki, M. Schüssler, F. Shapopi, J. N. S. Said, W. Si Sol, H. Stawarz, Ł. Steinmassl, S. Tanaka, T. Taylor, A. M. Taylor, G. L. Terrier, R. Tian, Y. Timmermans, A. Tsirou, M. Tsuji, N. Unbehaun, T. van Eldik, C. Vecchi, M. Venter, C. Vink, J. Voitsekhovskyi, V. Wagner, S. J. Wierzcholska, A. Zacharias, M. Zdziarski, A. A. Zech, A. Zhong, W. Takekawa, S.
author_facet	Acharyya, A. Aharonian, F. Ashkar, H. Backes, M. Batzofin, R. Berge, D. Bernlöhr, K. Böttcher, M. Boisson, C. Bolmont, J. Brun, F. Bruno, B. Burger-Scheidlin, C. Bylund, T. Casanova, S. Celic, J. Cerruti, M. Chen, A. Chernyakova, M. Chibueze, J. O. Chibueze, O. Cornejo, B. Cotter, G. Scarpin, J. de Assis de Lavergne, M. de Bony de Naurois, M. Wilhelmi, E. de Oña Giler, A. G. Delgado Devin, J. Djannati-Ataï, A. Dmytriiev, A. Egberts, K. Egg, K. Ernenwein, J. -P. Nieves, C. Escañuela Fauverge, P. Feijen, K. Filipovic, M. D. Fontaine, G. Funk, S. Gabici, S. Gallant, Y. A. Glicenstein, J. F. Glombitza, J. Goswami, P. Grondin, M. -H. Heckmann, L. Heß, B. Hinton, J. A. Hofmann, W. Holch, T. L. Holler, M. Jamrozy, M. Jankowsky, F. Jardin-Blicq, A. Jaroschewski, I. Jimeno, D. Jung-Richardt, I. Katarzyński, K. Kerszberg, D. Khélifi, B. Komin, N. Kosack, K. Kostunin, D. Lang, R. G. Lazarević, S. Lemière, A. Lemoine-Goumard, M. Lenain, J. -P. Liniewicz, P. Luashvili, A. Mackey, J. Malyshev, D. Marandon, V. Mayer, M. G. F. Mehta, A. Mitchell, A. M. W. Moderski, R. Mohrmann, L. Montanari, A. Moulin, E. Niemiec, J. Olivera-Nieto, L. Moghadam, M. O. Panny, S. Parsons, R. D. Pensec, U. Pichard, P. Preis, T. Pühlhofer, G. Punch, M. Quirrenbach, A. Reimer, A. Reimer, O. Reis, I. Remy, Q. Ren, H. X. Reville, B. Rieger, F. Roellinghoff, G. Rowell, G. Rudak, B. Sabri, K. Safi-Harb, S. Sahakian, V. Santangelo, A. Sasaki, M. Schüssler, F. Shapopi, J. N. S. Said, W. Si Sol, H. Stawarz, Ł. Steinmassl, S. Tanaka, T. Taylor, A. M. Taylor, G. L. Terrier, R. Tian, Y. Timmermans, A. Tsirou, M. Tsuji, N. Unbehaun, T. van Eldik, C. Vecchi, M. Venter, C. Vink, J. Voitsekhovskyi, V. Wagner, S. J. Wierzcholska, A. Zacharias, M. Zdziarski, A. A. Zech, A. Zhong, W. Takekawa, S.
contents	Microquasars have emerged as promising candidates to explain the cosmic-ray flux at petaelectronvolt energies. LHAASO observations revealed V4641~Sgr as the most extreme example so far. Using $\approx$100~h of H.E.S.S. data, we performed a spectro-morphological study of the gamma-ray emission around V4641~Sgr. We employed HI and dedicated CO observations of the region to infer the target material for cosmic-ray interactions. We detected multi-TeV emission around V4641~Sgr with a high significance. The emission region is elongated. We found a power-law spectrum with an index $\approx$1.8, and together with results from other gamma-ray instruments, this reveals a spectral energy distribution that peaks at energies of $\approx$100~TeV for the first time. We found indications (3$σ$) of a two-component morphology, with indistinguishable spectral properties. The position of V4641~Sgr is inconsistent with the best-fit position of the single-component model and with the dip between the two components. We found no significant evidence of an energy-dependent morphology. No dense gas was found at any distance towards V4641~Sgr. The peak of the SED at $\approx$100~TeV identifies V4641~Sgr as a candidate cosmic-ray accelerator beyond the so-called knee. The absence of dense target gas places stringent energetic constraints on hadronic interpretations, however. The H.E.S.S. measurement requires an unusually hard ($\approx 1.5$) spectral index for the protons. A leptonic scenario faces fewer obstacles if the particle transport is fast enough to avoid losses and to reproduce the observed energy-independent morphology. The absence of bright \xray emission across the gamma-ray emission region requires a magnetic field strength $\lesssim3$~$μ$G, however. Our findings favour a leptonic origin of the gamma-ray emission. This conclusion does not exclude hadron acceleration in the V4641~Sgr system.
format	Preprint
id	arxiv_https___arxiv_org_abs_2511_10537
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Constraining the nature of the most extreme Galactic particle accelerator. H.E.S.S. observations of the microquasar V4641 Sgr Acharyya, A. Aharonian, F. Ashkar, H. Backes, M. Batzofin, R. Berge, D. Bernlöhr, K. Böttcher, M. Boisson, C. Bolmont, J. Brun, F. Bruno, B. Burger-Scheidlin, C. Bylund, T. Casanova, S. Celic, J. Cerruti, M. Chen, A. Chernyakova, M. Chibueze, J. O. Chibueze, O. Cornejo, B. Cotter, G. Scarpin, J. de Assis de Lavergne, M. de Bony de Naurois, M. Wilhelmi, E. de Oña Giler, A. G. Delgado Devin, J. Djannati-Ataï, A. Dmytriiev, A. Egberts, K. Egg, K. Ernenwein, J. -P. Nieves, C. Escañuela Fauverge, P. Feijen, K. Filipovic, M. D. Fontaine, G. Funk, S. Gabici, S. Gallant, Y. A. Glicenstein, J. F. Glombitza, J. Goswami, P. Grondin, M. -H. Heckmann, L. Heß, B. Hinton, J. A. Hofmann, W. Holch, T. L. Holler, M. Jamrozy, M. Jankowsky, F. Jardin-Blicq, A. Jaroschewski, I. Jimeno, D. Jung-Richardt, I. Katarzyński, K. Kerszberg, D. Khélifi, B. Komin, N. Kosack, K. Kostunin, D. Lang, R. G. Lazarević, S. Lemière, A. Lemoine-Goumard, M. Lenain, J. -P. Liniewicz, P. Luashvili, A. Mackey, J. Malyshev, D. Marandon, V. Mayer, M. G. F. Mehta, A. Mitchell, A. M. W. Moderski, R. Mohrmann, L. Montanari, A. Moulin, E. Niemiec, J. Olivera-Nieto, L. Moghadam, M. O. Panny, S. Parsons, R. D. Pensec, U. Pichard, P. Preis, T. Pühlhofer, G. Punch, M. Quirrenbach, A. Reimer, A. Reimer, O. Reis, I. Remy, Q. Ren, H. X. Reville, B. Rieger, F. Roellinghoff, G. Rowell, G. Rudak, B. Sabri, K. Safi-Harb, S. Sahakian, V. Santangelo, A. Sasaki, M. Schüssler, F. Shapopi, J. N. S. Said, W. Si Sol, H. Stawarz, Ł. Steinmassl, S. Tanaka, T. Taylor, A. M. Taylor, G. L. Terrier, R. Tian, Y. Timmermans, A. Tsirou, M. Tsuji, N. Unbehaun, T. van Eldik, C. Vecchi, M. Venter, C. Vink, J. Voitsekhovskyi, V. Wagner, S. J. Wierzcholska, A. Zacharias, M. Zdziarski, A. A. Zech, A. Zhong, W. Takekawa, S. High Energy Astrophysical Phenomena Microquasars have emerged as promising candidates to explain the cosmic-ray flux at petaelectronvolt energies. LHAASO observations revealed V4641~Sgr as the most extreme example so far. Using $\approx$100~h of H.E.S.S. data, we performed a spectro-morphological study of the gamma-ray emission around V4641~Sgr. We employed HI and dedicated CO observations of the region to infer the target material for cosmic-ray interactions. We detected multi-TeV emission around V4641~Sgr with a high significance. The emission region is elongated. We found a power-law spectrum with an index $\approx$1.8, and together with results from other gamma-ray instruments, this reveals a spectral energy distribution that peaks at energies of $\approx$100~TeV for the first time. We found indications (3$σ$) of a two-component morphology, with indistinguishable spectral properties. The position of V4641~Sgr is inconsistent with the best-fit position of the single-component model and with the dip between the two components. We found no significant evidence of an energy-dependent morphology. No dense gas was found at any distance towards V4641~Sgr. The peak of the SED at $\approx$100~TeV identifies V4641~Sgr as a candidate cosmic-ray accelerator beyond the so-called knee. The absence of dense target gas places stringent energetic constraints on hadronic interpretations, however. The H.E.S.S. measurement requires an unusually hard ($\approx 1.5$) spectral index for the protons. A leptonic scenario faces fewer obstacles if the particle transport is fast enough to avoid losses and to reproduce the observed energy-independent morphology. The absence of bright \xray emission across the gamma-ray emission region requires a magnetic field strength $\lesssim3$~$μ$G, however. Our findings favour a leptonic origin of the gamma-ray emission. This conclusion does not exclude hadron acceleration in the V4641~Sgr system.
title	Constraining the nature of the most extreme Galactic particle accelerator. H.E.S.S. observations of the microquasar V4641 Sgr
topic	High Energy Astrophysical Phenomena
url	https://arxiv.org/abs/2511.10537