Issue |
A&A
Volume 672, April 2023
|
|
---|---|---|
Article Number | A103 | |
Number of page(s) | 23 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361/202245459 | |
Published online | 06 April 2023 |
HESS J1809−193: A halo of escaped electrons around a pulsar wind nebula?
1
Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland
2
Max-Planck-Institut für Kernphysik, PO Box 103980 69029 Heidelberg, Germany
3
Landessternwarte, Universität Heidelberg, Königstuhl, 69117 Heidelberg, Germany
4
Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands
5
Laboratoire Leprince-Ringuet, École Polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau, France
6
University of Namibia, Department of Physics, Private Bag 13301, Windhoek 10005, Namibia
7
Centre for Space Research, North-West University, Potchefstroom 2520, South Africa
8
DESY, 15738 Zeuthen, Germany
9
School of Physics, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg 2050, South Africa
10
Université de Paris, CNRS, Astroparticule et Cosmologie, 75013 Paris, France
11
Department of Physics and Electrical Engineering, Linnaeus University, 351 95 Växjö, Sweden
12
Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany
13
Laboratoire Univers et Théories, Observatoire de Paris, Université PSL, CNRS, Université de Paris, 92190 Meudon, France
14
Sorbonne Université, Université Paris-Diderot, Sorbonne Paris-Cité, CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Énergies, LPNHE, 4 place Jussieu, 75252 Paris, France
15
IRFU, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
16
Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen, Germany
17
Astronomical Observatory, The University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw, Poland
18
Université Savoie Mont Blanc, CNRS, Laboratoire d’Annecy de Physique des Particules – IN2P3, 74000 Annecy, France
19
Instytut Fizyki Jdrowej PAN, ul. Radzikowskiego 152, 31-342 Kraków, Poland
20
Université Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, 33170 Gradignan, France
21
School of Physical Sciences, University of Adelaide, Adelaide 5005, Australia
22
Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France
23
School of Science, Western Sydney University, Locked Bag 1797, Penrith South DC, NSW 2751, Australia
24
Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, CC 72, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
25
Institut für Astro- und Teilchenphysik, Leopold-Franzens-Universität Innsbruck, 6020 Innsbruck, Austria
26
Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg, Germany
27
Obserwatorium Astronomiczne, Uniwersytet Jagielloński, ul. Orla 171, 30-244 Kraków, Poland
28
Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
29
Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, Poland
30
Institut für Astronomie und Astrophysik, Universität Tübingen, Sand 1, 72076 Tübingen, Germany
31
GRAPPA, Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
32
Yerevan Physics Institute, 2 Alikhanian Brothers St., 375036 Yerevan, Armenia
33
Department of Physics, Konan University, 8-9-1 Okamoto, Higashinada, Kobe, Hyogo 658-8501, Japan
34
Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8583, Japan
35
RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
36
Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
Received:
14
November
2022
Accepted:
24
February
2023
Context. HESS J1809−193 is an unassociated very-high-energy γ-ray source located on the Galactic plane. While it has been connected to the nebula of the energetic pulsar PSR J1809−1917, supernova remnants and molecular clouds present in the vicinity also constitute possible associations. Recently, the detection of γ-ray emission up to energies of ∼100 TeV with the HAWC observatory has led to renewed interest in HESS J1809−193.
Aims. We aim to understand the origin of the γ-ray emission of HESS J1809−193.
Methods. We analysed 93.2 h of data taken on HESS J1809−193 above 0.27 TeV with the High Energy Stereoscopic System (H.E.S.S.), using a multi-component, three-dimensional likelihood analysis. In addition, we provide a new analysis of 12.5 yr of Fermi-LAT data above 1 GeV within the region of HESS J1809−193. The obtained results are interpreted in a time-dependent modelling framework.
Results. For the first time, we were able to resolve the emission detected with H.E.S.S. into two components: an extended component (modelled as an elongated Gaussian with a 1-σ semi-major and semi-minor axis of ∼0.62° and ∼0.35°, respectively) that exhibits a spectral cutoff at ∼13 TeV, and a compact component (modelled as a symmetric Gaussian with a 1-σ radius of ∼0.1°) that is located close to PSR J1809−1917 and shows no clear spectral cutoff. The Fermi-LAT analysis also revealed extended γ-ray emission, on scales similar to that of the extended H.E.S.S. component.
Conclusions. Our modelling indicates that based on its spectrum and spatial extent, the extended H.E.S.S. component is likely caused by inverse Compton emission from old electrons that form a halo around the pulsar wind nebula. The compact component could be connected to either the pulsar wind nebula or the supernova remnant and molecular clouds. Due to its comparatively steep spectrum, modelling the Fermi-LAT emission together with the H.E.S.S. components is not straightforward.
Key words: acceleration of particles / radiation mechanisms: non-thermal / pulsars: individual: PSR J1809-1917 / gamma rays: general
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Open access funding provided by Max Planck Society.
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