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用MAGIC对NGC 1275区的深观测:英仙座星团中宇宙射线的弥散gamma-ray发射的搜索

Deep observation of the NGC 1275 region with MAGIC: search of diffuse gamma-ray emission from cosmic rays in the Perseus cluster

MAGIC Collaboration, M. L. Ahnen, S. Ansoldi, L. A. Antonelli, P. Antoranz, A. Babic, B. Banerjee, P. Bangale, U. Barres de Almeida, J. A. Barrio, J. Becerra Go… 展开作者

MAGIC Collaboration, M. L. Ahnen, S. Ansoldi, L. A. Antonelli, P. Antoranz, A. Babic, B. Banerjee, P. Bangale, U. Barres de Almeida, J. A. Barrio, J. Becerra González, W. Bednarek, E. Bernardini, B. Biasuzzi, A. Biland, O. Blanch, S. Bonnefoy, G. Bonnoli, F. Borracci, T. Bretz, S. Buson, E. Carmona, A. Carosi, A. Chatterjee, R. Clavero, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, E. de Oña Wilhelmi, C. Delgado Mendez, F. Di Pierro, A. Domínguez, D. Dominis Prester, D. Dorner, M. Doro, S. Einecke, D. Eisenacher Glawion, D. Elsaesser, A. Fernández-Barral, D. Fidalgo, M. V. Fonseca, L. Font, K. Frantzen, C. Fruck, D. Galindo, R. J. García López, M. Garczarczyk, D. Garrido Terrats, M. Gaug, P. Giammaria, N. Godinović, A. González Muñoz, D. Gora, D. Guberman, D. Hadasch, A. Hahn, Y. Hanabata, M. Hayashida, J. Herrera, J. Hose, D. Hrupec, G. Hughes, W. Idec, K. Kodani, Y. Konno, H. Kubo, J. Kushida, A. La Barbera, D. Lelas, E. Lindfors, S. Lombardi, F. Longo, M. López, R. López-Coto, E. Lorenz, P. Majumdar, M. Makariev, K. Mallot, G. Maneva, M. Manganaro, K. Mannheim, L. Maraschi, B. Marcote, M. Mariotti, M. Martínez, D. Mazin, U. Menzel, J. M. Miranda, R. Mirzoyan, A. Moralejo, E. Moretti, D. Nakajima, V. Neustroev, A. Niedzwiecki, M. Nievas Rosillo, K. Nilsson, K. Nishijima, K. Noda, R. Orito, A. Overkemping, S. Paiano, J. Palacio, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, X. Paredes-Fortuny, G. Pedaletti, M. Persic, J. Poutanen, P. G. Prada Moroni, E. Prandini, I. Puljak, W. Rhode, M. Ribó, J. Rico, J. Rodriguez Garcia, T. Saito, K. Satalecka, C. Schultz, T. Schweizer, A. Sillanpää, J. Sitarek, I. Snidaric, D. Sobczynska, A. Stamerra, T. Steinbring, M. Strzys, L. Takalo, H. Takami, F. Tavecchio, P. Temnikov, T. Terzić, D. Tescaro, M. Teshima, J. Thaele, D. F. Torres, T. Toyama, A. Treves, M. Vazquez Acosta, V. Verguilov, I. Vovk, J. E. Ward, M. Will, M. H. Wu, R. Zanin, and, :, C. Pfrommer, A. Pinzke, F. Zandanel

摘要:

星系团被认为是宇宙射线(CR)的储存库,由于它们与星系团内介质的强子相互作用,CR应该产生弥散的伽马射线辐射。附近的英仙座冷核星团被认为是寻找这种发射的最有希望的目标,从2009年到2014年,MAGIC望远镜在非常高的能量(VHE,E>100 GeV)下观测了253小时。在第一阶段的观测中,星系团中央的主导星系NGC 1275和距离中心约0.6 $^\circ$的IC 310的活动核被探测为点状VHE伽马射线发射体。我们报告的NGC 1275光谱,这是很好地描述了幂律与$3.6\pm0.2_{stat}\pm0.2_{syst}$的光子指数之间的90 GeV和1.2 TeV的更新测量。我们没有检测到任何弥漫的伽马射线发射的集群,并设置严格的限制其CR人口。为了将CR空间和光谱分布上的不确定性进行分类,我们采用了不同的空间模板和幂律谱指数$α$。对于$α=2.2$,在团簇维里半径内的CR-热压力被约束为低于1- 2%,除非CR可以传播到团簇核心之外,从而产生更平坦的径向分布并将CR-热压力约束释放到<20%。假设观测到的英仙座射电小晕是由CR强子相互作用的次级电子产生的,我们可以推导出中心磁场的下限,$B_0$,这取决于CR分布。对于$α=2.2$,$B_0\gtrsim5-8 μ$ G,它低于从法拉第旋转测量推断的25 $μ$ G,而对于$α\lesssim2.1$,漫射射电辐射的强子解释与我们的伽马射线通量上限无关的磁场强度相反。

英文摘要:

Clusters of galaxies are expected to be reservoirs of cosmic rays (CRs) that should produce diffuse gamma-ray emission due to their hadronic interactions with the intra-cluster medium. The nearby Perseus cool-core cluster, identified as the most promising target to search for such an emission, has been observed with the MAGIC telescopes at very-high energies (VHE, E>100 GeV) for a total of 253 hr from 2009 to 2014. The active nuclei of NGC 1275, the central dominant galaxy of the cluster, and IC 310, lying at about 0.6$^\circ$ from the centre, have been detected as point-like VHE gamma-ray emitters during the first phase of this campaign. We report an updated measurement of the NGC 1275 spectrum, which is well described by a power law with a photon index of $3.6\pm0.2_{stat}\pm0.2_{syst}$ between 90 GeV and 1.2 TeV. We do not detect any diffuse gamma-ray emission from the cluster and set stringent constraints on its CR population. In order to bracket the uncertainties over the CR spatial and spectral distributions, we adopt different spatial templates and power-law spectral indexes $α$. For $α=2.2$, the CR-to-thermal pressure within the cluster virial radius is constrained to be below 1-2%, except if CRs can propagate out of the cluster core, generating a flatter radial distribution and releasing the CR-to-thermal pressure constraint to <20%. Assuming that the observed radio mini-halo of Perseus is generated by secondary electrons from CR hadronic interactions, we can derive lower limits on the central magnetic field, $B_0$, that depend on the CR distribution. For $α=2.2$, $B_0\gtrsim5-8 μ$G, which is below the 25 $μ$G inferred from Faraday rotation measurements, whereas, for $α\lesssim2.1$, the hadronic interpretation of the diffuse radio emission is in contrast with our gamma-ray flux upper limits independently of the magnetic field strength.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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