Extended Data Figure 1: Cooling times of electrons in the Galactic Centre as a function of energy.
From: Acceleration of petaelectronvolt protons in the Galactic Centre
The cooling times (τcool) due to ionization (or Coulomb) losses and bremsstrahlung are inversely proportional to the gas density n; here n = 100 cm−3 is assumed. The cooling time of the synchrotron radiation is proportional to 1/B2, where B is the magnetic field. The synchrotron cooling times are given for magnetic fields B = 10 μG and B = 100 μG. The total energy densities of the cosmic microwave background and of local near-infrared (NIR) and far-infrared (FIR) infrared radiation fields used to calculated the cooling time due to the IC scattering are extracted from the GALPROP code47. The integrated densities are 17.0 eV cm3 and 1.3 eV cm3 for NIR and FIR, respectively.
