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Deep observations of the globular cluster M15 with the MAGIC telescopes |
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| Author: | Acciari, V. A.1,2; Ansoldi, S.3,4,5; Antonelli, L. A.6,7; |
| Organizations: |
1Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. 2Univ La Laguna, Dept Astrofis, E-38206 San Cristobal la Laguna, Tenerife, Spain. 3Univ Udine, I-33100 Udine, Italy.
4INFN Trieste, I-33100 Udine, Italy.
5Univ Autonoma Barcelona, Dept Fis, E-08193 Bellaterra, Spain. 6Univ Autonoma Barcelona, CERES IEEC, E-08193 Bellaterra, Spain. 7Natl Inst Astrophys INAF, I-00136 Rome, Italy. 8Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. 9Tech Univ Dortmund, D-44221 Dortmund, Germany. 10Univ Rijeka, Croatian MAGIC Consortium, Zagreb 10000, Croatia. 11HBNI, Saha Inst Nucl Phys, 1-F Bidhannagar,Sect 1, Kolkata 700064, India. 12URCA, CBPF, Rio De Janeiro, RJ, Brazil. 13Univ Complutense, Unidad Particulas & Cosmol UPARCOS, E-28040 Madrid, Spain. 14Univ Lodz, Dept Astrophys, PL-90236 Lodz, Poland. 15Deutsch Elektronen Synchrotron DESY, D-15738 Zeuthen, Germany. 16Univ Padua, I-35131 Padua, Italy. 17INFN, I-35131 Padua, Italy. 18Humboldt Univ, Inst Phys, D-12489 Berlin, Germany. 19INFN, I-00044 Rome, Italy. 20Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy. 21BIST, IFAE, E-08193 Bellaterra, Barcelona, Spain. 22Univ Siena, I-53100 Siena, Italy. 23INFN Pisa, I-53100 Siena, Italy. 24Univ Pisa, I-56126 Pisa, Italy. 25INFN Pisa, I-56126 Pisa, Italy. 26PIC, E-08193 Bellaterra, Barcelona, Spain. 27Max Planck Inst Phys & Astrophys, D-80805 Munich, Germany. 28Univ Wurzburg, D-97074 Wurzburg, Germany. 29Univ Barcelona, ICCUB, IEEC UB, E-08028 Barcelona, Spain. 30NAS RA, ICRANet Armenia, Yerevan 0019, Armenia. 31Univ Tokyo, ICRR, Japanese MAGIC Consortium:, Tokyo, Chiba 2778582, Japan. 32Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. 33Tokai Univ, Kanagawa 2591292, Japan. 34Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, BG-1784 Sofia, Bulgaria. 35Univ Oulu, Astron Div, Oulu, Finland. 36Univ Bologna, Dept Phys & Astron, I-40126 Bologna, Italy. |
| Format: | article |
| Version: | published version |
| Access: | open |
| Online Access: | PDF Full Text (PDF, 1.2 MB) |
| Persistent link: | http://urn.fi/urn:nbn:fi-fe202003097662 |
| Language: | English |
| Published: |
Oxford University Press,
2019
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| Publish Date: | 2020-03-09 |
| Description: |
AbstractA population of globular clusters (GCs) has been recently established by the Fermi-LAT telescope as a new class of GeV γ-ray sources. Leptons accelerated to TeV energies, in the inner magnetospheres of MSPs or in their wind regions, should produce γ-rays through the inverse Compton scattering in the dense radiation field from the huge population of stars. We have conducted deep observations of the GC M15 with the MAGIC telescopes and used 165 h in order to search for γ-ray emission. A strong upper limit on the TeV γ-ray flux < 3.2×10−13cm−2s−1 above 300 GeV (<0.26 per cent of the Crab nebula flux) has been obtained. We interpret this limit as a constraint on the efficiency of the acceleration of leptons in the magnetospheres of the MSPs. We constrain the injection rate of relativistic leptons, ηe, from the MSPs magnetospheres and their surrounding. We conclude that ηe must be lower than expected from the modelling of high-energy processes in MSP inner magnetospheres. For leptons accelerated with the power-law spectrum in the MSP wind regions, ηe is constrained to be much lower than derived for the wind regions around classical pulsars. These constraints are valid for the expected range of magnetic field strengths within the GC and for the range of likely energies of leptons injected from the inner magnetospheres, provided that the leptons are not removed from the GC very efficiently due to advection process. We discuss consequences of these constraints for the models of radiation processes around millisecond pulsars. see all
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| Series: |
Monthly notices of the Royal Astronomical Society |
| ISSN: | 0035-8711 |
| ISSN-E: | 1365-8711 |
| ISSN-L: | 0035-8711 |
| Volume: | 484 |
| Issue: | 2 |
| Pages: | 2876 - 2885 |
| DOI: | 10.1093/mnras/stz179 |
| OADOI: | https://oadoi.org/10.1093/mnras/stz179 |
| Type of Publication: |
A1 Journal article – refereed |
| Field of Science: |
115 Astronomy and space science |
| Subjects: | |
| Funding: |
The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish Ministry of Economy and Competitiveness (MINECO) (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, FPA2017-90566-REDC), the Indian Department of Atomic Energy and the Japanese Japan Society of for the Promotion of Science (JSPS) and Ministry of Education, Culture, Sports, Science and Technology (MEXT) is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia ‘Severo Ochoa’ SEV-2016-0588 and SEV-2015-0548, and Unidad de Excelencia ‘María de Maeztu’ MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the German Research Fundation (DFG) Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ. This work is also supported by the grant through the Polish National Research Centre No. 2014/15/B/ST9/04043. |
| Copyright information: |
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). |