Abstract
Abstract
Solar active region NOAA 14455 hosted an X1.0 flare on 3 June 2026 whose soft X- ray emission began to rise at 11:19 UTC and peaked at 11:28 UTC. This paper examines the photospheric and atmospheric behaviour of the region across an interval extending roughly three hours on either side of the event, using continuum intensity and line- of-sight magnetograms from the Helioseismic and Magnetic Imager, image sequences from the Atmospheric Imaging Assembly in the 1700, 304, 171 and 131 ˚A passbands, and soft X-ray photometry from GOES. Three quantities are followed: the umbral and penumbral contributions to the projected sunspot area, the signed photospheric magnetic flux integrated over a fixed region of interest, and the morphology of the flare-related emission. Between 08:25 and 11:25 UTC the sunspot area grew from 360.1 to 369.0 millionths of the solar hemisphere (MSH) and the net magnetic flux from 1.421 × 10 to 1.456 ×10 Mx. The area continued to rise after the X-ray peak, reaching a maximum of 370.2 MSH at 12:25 UTC before falling to 352.4 MSH by 14:25 UTC, whereas the net flux declined to a minimum of 1.271 ×1022 Mx at 13:25 UTC and recovered partially to 1.355 ×1022 Mx. A smaller sub-region selected for showing the strongest magnetic changes exhibits much larger relative swings, its net flux reversing sign in the hour before onset. The X-ray and extreme-ultraviolet records show a sharp, spatially localised brightening that is nearly simultaneous in all four passbands. These measurements indicate that the reorganisation accompanying the flare involved the photosphere and chromosphere as well as the corona, and that the response was concentrated in the structures surrounding a comparatively quiescent central sunspot.