High-Resolution Observations of Multiwavelength Emissions during Two X-Class White-Light Flares

• Published in: The Astrophysical journal Vol. 641; no. 2; pp. 1210 - 1216
• Main Authors: Xu, Yan, Cao, Wenda, Liu, Chang, Yang, Guo, Jing, Ju, Denker, Carsten, Emslie, A. Gordon, Wang, Haimin
• Format: Journal Article
• Language: English
• Published: Chicago, IL IOP Publishing 20.04.2006; University of Chicago Press
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Sun: flares; Multifrequency observation; Sun: photosphere; Sun: activity; Sun
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/500632

We observed two X-class white-light flares (WLFs) on 2003 October 29 (620:40 UT) and November 2 (617:16 UT) using the Dunn Solar Telescope (DST) and its High-Order Adaptive Optics (HOAO) system in several wavelengths. The spatial resolution was close to the diffraction limit of DST's 76 cm aperture, and the cadence was as high as 2 s. This is the first time that WLFs have been observed in the near-infrared (NIR) wavelength region. We present a detailed study in this paper comparing photospheric continuum observations during the two events with corresponding line-of-sight magnetograms from the Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI) and hard X-ray (HXR) data from the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). We also discuss several models that provide possible mechanisms to explain these continuum enhancements, especially in the NIR.