M dwarfs are the most common type of star in the solar neighborhood, and many exhibit frequent and highly energetic flares. To better understand these events across the electromagnetic spectrum, a campaign observed AU Mic over 7 days in October 2018 from the X-ray to radio regimes. Tristan et al. present high-time-resolution light curves from the Very Large Array (VLA) and the ATCA which observe gyrosynchrotron radiation and directly probe the action of accelerated electrons within flaring loops. Observations reveal 16 VLA and 3 ATCA flares of varying shapes and sizes, from a short (30 sec) spiky burst to a long-duration (∼5 hr) decaying exponential. Both rising and falling spectra are observed in the Ku-band, indicating optically thick and thin flares, respectively. Estimates of the total kinetic energies of gyrating electrons in optically thin flares and local magnetic field strengths are able to explain the combined radiated energies from multi-wavelength observations. Overall, values are more aligned with modern radiative-hydrodynamic simulations of M dwarf flares, and future modeling efforts will better constrain findings. The figure above shows Xmm X-ray satellite light curves that overlap with the ATCA observations. The vertical blue lines correspond to the radio flare peaks, and Flare IDs are labeled to the right of each flare.
