使用Magic和Fermi-Lat的$γ$ -CYGNI SNR（G78.2+2.1）的GEV到TEV形态的研究

论文标题

使用Magic和Fermi-Lat的$γ$ -CYGNI SNR（G78.2+2.1）的GEV到TEV形态的研究

Study of the GeV to TeV morphology of the $γ$-Cygni SNR (G78.2+2.1) with MAGIC and Fermi-LAT

论文作者

MAGIC Collaboration, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Baack, D., Babić, A., Banerjee, B., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Espiñeira, E. Do Souto, Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Loporchio, S., Fraga, B. Machado de Oliveira, Masuda, S., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Mender, S., Mićanović, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Peñil, P., Peresano, M., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tosti, L., van Scherpenberg, J., Vanzo, G., Acosta, M. Vazquez, Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zarić, D., authors, External, :, Celli, S., Morlino, G.

论文摘要

语境。扩散冲击加速度（DSA）是在超新星残留物（SNRS）冲击中加速银河宇宙射线（CRS）的最有希望的机制。据称，上游的湍流是由CRS产生的，但是该过程尚未得到充分理解。主要机制可能取决于冲击的进化状态，可以通过CRS逃脱到星际介质（ISM）的CRS进行研究。目标。先前对$γ$ -CYGNI SNR的观察结果表明，GEV和TEV能量之间的形态差异。由于该SNR的年龄是正确的，并且处于CRS大量逃脱的进化阶段，因此我们旨在了解$γ$ -CYGNI SNR附近的$γ$ -Ray射击。方法。我们在2015年5月至2017年9月在2015年5月至2017年9月之间观察到$γ$ -CYGNI SNR的区域，其魔术大气Cherenkov望远镜的区域记录了87小时的优质数据。此外，我们分析了费米 - 拉特数据，以研究形态学的能量依赖性以及GEV到TEV范围的能量光谱。将能源光谱和形态与理论预测进行了比较，这些预测包括CR逃逸过程的详细推导及其$γ$ ray的产生。结果。魔术和费米 - 拉特数据使我们能够识别三个发射区域，它们可以与SNR相关联并在不同的能量下占主导地位。我们的HADRONIC发射模型很好地说明了所有源成分的形态和能源。它限制了CRS在冲击时的最大能量的时间依赖性，湍流水平的时间依赖性以及紧接在SNR冲击以外的扩散系数。尽管与DSA的标准图片一致，但发现最大能量的时间依赖性比预测的要陡峭，并且发现湍流水平在SNR的寿命中会发生变化。

Context. Diffusive shock acceleration (DSA) is the most promising mechanism to accelerate Galactic cosmic rays (CRs) in the shocks of supernova remnants (SNRs). The turbulence upstream is supposedly generated by the CRs, but this process is not well understood. The dominant mechanism may depend on the evolutionary state of the shock and can be studied via the CRs escaping upstream into the interstellar medium (ISM). Aims. Previous observations of the $γ$-Cygni SNR showed a difference in morphology between GeV and TeV energies. Since this SNR has the right age and is at the evolutionary stage for a significant fraction of CRs to escape, we aim to understand $γ$-ray emission in the vicinity of the $γ$-Cygni SNR. Methods. We observed the region of the $γ$-Cygni SNR with the MAGIC Imaging Atmospheric Cherenkov telescopes between May 2015 and September 2017 recording 87 h of good-quality data. Additionally we analysed Fermi-LAT data to study the energy dependence of the morphology as well as the energy spectrum in the GeV to TeV range. The energy spectra and morphology were compared against theoretical predictions, which include a detailed derivation of the CR escape process and their $γ$-ray generation. Results. The MAGIC and Fermi-LAT data allowed us to identify three emission regions, which can be associated with the SNR and dominate at different energies. Our hadronic emission model accounts well for the morphology and energy spectrum of all source components. It constrains the time-dependence of the maximum energy of the CRs at the shock, the time-dependence of the level of turbulence, and the diffusion coefficient immediately outside the SNR shock. While in agreement with the standard picture of DSA, the time-dependence of the maximum energy was found to be steeper than predicted and the level of turbulence was found to change over the lifetime of the SNR.

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