Ultrahigh-Energy Gamma-ray Emission Associated with Black Hole-Jet Systems
astro-ph.HE
/ Authors
The LHAASO Collaboration, Zhen Cao, Felix Aharonian, Yun-Xiang Bai, Yi-Wei Bao, Denis Bastieri, Xiao-Jun Bi, Yu-Jiang Bi, Wen-Yi Bian, Anatoly V Bukevich
and 308 more authors
Chengmiao Cai, Wen-Yu Cao, Zhe Cao, Jin Chang, Jin-Fan Chang, Aming Chen, En-Sheng Chen, Guohai Chen, Hua-Xi Chen, Liang Chen, Long Chen, Ming-Jun Chen, Ma-Li Chen, Qi-Hui Chen, Shi Chen, Su-Hong Chen, Song-Zhan Chen, Tian-Lu Chen, Xiao-Bin Chen, Xuejian Chen, Yang Chen, Ning Cheng, Yao-Dong Cheng, Ming Chung Chu
/ Abstract
Black holes (BH), one of the most intriguing objects in the universe, can manifest themselves through electromagnetic radiation initiated by the accretion flow. Some stellar-mass BHs drive relativistic jets when accreting matter from their companion stars, forming microquasars. Non-thermal emission from the radio to tera-electronvolt (TeV) gamma-ray band has been observed from microquasars, indicating the acceleration of relativistic particles. Here we report detection of four microquasars (SS 433, V4641 Sgr, GRS 1915+105, MAXI J1820+070) of spectrum extending to the ultrahigh-energy (UHE; photon energy $E>100$ TeV) band and one microquasar (Cygnus X-1) of spectrum approaching 100 TeV, using the Large High Altitude Air Shower Observatory (LHAASO). Notably, the total emission associated with SS 433 cannot be interpreted with a single leptonic component. In the UHE band, its emission is in spatial coincidence with a giant atomic cloud, which is consistent with a hadronic origin. An elongated source is discovered from V4641 Sgr with the spectrum continuing up to 800 TeV. The detection of UHE gamma rays demonstrates that accreting BHs and their environments can operate as extremely efficient accelerators of particles out of 1 peta-electronvolt (PeV), suggesting microquasars to be important contributors to Galactic cosmic rays especially around the `knee' region.