Hot coronal loops associated with umbral brightenings

C. E. Alissandrakis; S. Patsourakos

doi:10.1051/0004-6361/201321787

Free Access

Issue		A&A Volume 556, August 2013


Article Number		A79
Number of page(s)		5
Section		The Sun
DOI		https://doi.org/10.1051/0004-6361/201321787
Published online		31 July 2013

A&A 556, A79 (2013)

Hot coronal loops associated with umbral brightenings^⋆

C. E. Alissandrakis and S. Patsourakos

Department of Physics, University of Ioannina, 45110 Ioannina, Greece
calissan@cc.uoi.gr; spatsour@cc.uoi.gr

Received: 26 April 2013
Accepted: 21 June 2013

Abstract

Aims. We aim to investigate the association of umbral brightenings with coronal structures.

Methods. We analyzed AIA/SDO high-cadence images in all bands, HMI/SDO data, soft X-ray images from SXI/GOES-15, and Hα images from the GONG network.

Results. We detected umbral brightenings that were visible in all AIA bands as well as in Hα. Moreover, we identified hot coronal loops that connected the brightenings with nearby regions of opposite magnetic polarity. These loops were initially visible in the 94 Å band, subsequently in the 335 Å band, and in one case in the 211 Å band. A differential emission measure analysis revealed plasma with an average temperature of about 6.5 × 10⁶ K. This behavior suggests cooling of impulsively heated loops.

Key words: sunspots / Sun: corona / Sun: magnetic topology

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Two movies are available in electronic from at http://www.aanda.org

© ESO, 2013

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Hot coronal loops associated with umbral brightenings⋆

Hot coronal loops associated with umbral brightenings^⋆