A Seven-day Multiwavelength Flare Campaign on AU Mic. III. Quiescent and Flaring Properties of the X-Ray Spectra and Chromospheric Lines Journal Article uri icon

Overview

abstract

  • Abstract; ; We present the X-ray quiescent and flaring properties from a unique, 7 days multiwavelength observing campaign on the M1 flare star AU Mic. Combining the XMM-Newton X-ray spectra with the chromospheric line and broadband near-UV (NUV) and optical continuum observations provides a data set that is one of the most comprehensive to date. We analyze the sample of 38 X-ray flares and study in detail the X-ray flare temperature (; T; ) and emission measure (EM) evolutions of three largest flares with the X-ray flare energies of >10; 33; erg. The; T; –EM evolution tracks and multiwavelength emission evolutions of the largest-amplitude Neupert-type flare reveal that the so-called “Flare H–R diagram” is consistent with thermal coronal flare emission evolution. The two other more gradual and longer duration X-ray flares are interpreted as having larger size scales. None of the 17 H; α; and H; β; flares show clear blue/red wing asymmetries, including the ones associated with the potential X-ray dimming event previously reported. The above largest-amplitude Neupert flare shows clear symmetric H; α; and H; β; broadenings with roughly ±400 and ±600 km s; −1; , respectively, which are synchronized with the optical/NUV continuum emission evolution. Radiative hydrodynamic modeling results suggest that electron beam heating parameters that have been used to reproduce M dwarf flare NUV/optical continuum emissions can reproduce these large broadenings of H; α; and H; β; lines. These results suggest that these most energetic M dwarf flares are associated with stronger magnetic field flux densities and larger size scales than solar flares but can be interpreted in terms of the standard flare model.;

publication date

  • November 10, 2025

Date in CU Experts

  • November 12, 2025 8:54 AM

Full Author List

  • Notsu Y; Tristan II; Osten RA; Brown A; Kowalski AF; Grady CA

author count

  • 6

Other Profiles

International Standard Serial Number (ISSN)

  • 0004-637X

Electronic International Standard Serial Number (EISSN)

  • 1538-4357

Additional Document Info

start page

  • 212

end page

  • 212

volume

  • 993

issue

  • 2