Post-flare evolution of AR 10923 with Hinode/XRT

¹ Institut d'Astrophysique Spatiale, Univ. Paris Sud, 91405 Orsay Cedex, France
² Royal Observatory of Belgium, 3 Av. Circulaire, 1180 Bruxelles, Belgium e-mail: s.parenti@oma.be
³ Dip. di Science Fisiche ed Astronomiche, Univ. di Palermo 1, 90134 Palermo, Italy
⁴ INAF-Osservatorio Astronomico di Palermo G. S. Vaiana, Piazza del Parlamento 1, 90134 Palermo, Italy
⁵ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS 58, Cambridge, MA 02138, USA

Received: 19 November 2009
Accepted: 2 March 2010

Abstract

Context. Flares are dynamic events which involve rapid changes in coronal magnetic topology end energy release. Even if they may be localized phenomena, the magnetic disturbance at their origin may propagate and be effective in a larger part of the active region.

Aims. We investigate the temporal evolution of a flaring active region with respect to the loops morphology, the temperature, and emission measure distributions.

Methods. We consider Hinode/XRT data of a the 2006 November 12th C1.1 flare. We inspect the evolution of the morphology of the flaring region also with the aid of TRACE data. XRT filter ratios are used to derive temperature and emission measure maps and evolution.

Results. The analyzed flare includes several brightenings. We identify a coherent sequence of tangled and relaxed loop structures before, during, and after the brightenings. Although the thermal information is incomplete because of pixel saturation at the flare peak, thermal maps show fine, evolving spatial structuring. Temperature and emission measure variations show up in great detail, and we are able to detect a secondary heating of larger loops close to the proper flaring region. Finally we estimate the amount of energy released in these flaring loops during the flare decay.