Reporters learned from the Institute of High Energy Physics of the Chinese Academy of Sciences on the 8th that, relying on the observation data of the High Altitude Cosmic Ray Observatory (LHAASO, referred to as "Lasso"), researchers from the Institute and other institutions have for the first time detected ultrahigh energy gamma ray signals with energy exceeding 100 trillion electron volts in a special celestial system in the Milky Way. This discovery will push the observation level of such celestial bodies to new heights and directly challenge existing particle acceleration theories. The relevant achievements were published online in the Physics Review Letters and were selected as "Editor's Recommendations" articles and "Physics Features". Cosmic rays are high-energy particles from outer space, mainly composed of protons and other atomic nuclei, and their origin is known as the "mystery of the century". Due to the fact that the energy of gamma photons generated by proton collisions is usually about one tenth of the energy of protons, detecting photons from celestial bodies with energies exceeding one million electron volts has become one of the main ways to certify "super accelerators". A gamma ray binary consisting of a massive star and a dense star is a natural laboratory for exploring such extreme physical processes and a potential source of cosmic ray acceleration. LS I+61 ° 303 is a classic gamma ray binary star. In the past, people observed that its radiation energy was no more than 10 trillion electron volts, and it is unknown whether there is still a signal in the higher energy range. This time, with the ultra-high sensitivity and wide energy coverage capability of "Lasso", researchers have extended the gamma ray spectrum of LS I+61 ° 303 to 200 trillion electron volts for the first time, officially certifying it as a "ultra-high energy gamma ray binary". More interestingly, they also found that the radiation intensity of the system varies regularly with an orbital period of about 26.5 days, and this' orbital modulation 'effect has a significant energy dependence. This phenomenon indicates that there are extremely complex physical processes inside gamma ray binary systems. ”Li Cong, the co corresponding author of the paper and associate researcher of the Institute of High Energy Physics of the Chinese Academy of Sciences, said that when a dense star is close to a massive companion, the strong magnetic field will make high-energy electrons rapidly lose energy through synchrotron radiation, and it is difficult for the traditional acceleration model to push electrons to ultrahigh energy in this narrow and strong magnetic field environment. The photons detected this time, exceeding 100 trillion electron volts, strongly suggest that at a specific stage of the orbit, high-energy protons (hadrons) may have overcome numerous obstacles and collided with the dense stellar wind material around them, producing these ultra-high energy gamma rays. Li Cong stated that the achievement of "Lasso" proves that gamma ray binary stars are a potential source of electron phonon acceleration, and provides a new probe for exploring particle acceleration and radiation mechanisms in extreme physical environments, providing a new direction for future research in multi messenger astronomy. (Looking into the New Era)