Astronomy & Astrophysics

Free access article

A&A 481, L45-L48 (2008)
DOI: 10.1051/0004-6361:20079019

Letter

An intriguing solar microflare observed with RHESSI, Hinode, and TRACE

I. G. Hannah¹, S. Krucker¹, H. S. Hudson¹, S. Christe^{1, 2}, and R. P. Lin^{1, 2}

¹ Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, 94720-7450, USA
e-mail: hannah@ssl.berkeley.edu
² Physics Department, University of California at Berkeley, Berkeley, CA, 94720-7450, USA

(Received 8 November 2007 / Accepted 3 December 2007)

Abstract
Aims.We investigate particle acceleration and heating in a solar microflare.
Methods.In a microflare with non-thermal emission to remarkably high energies (>50 keV), we investigate the hard X-rays with RHESSI imaging and spectroscopy and the resulting thermal emission seen in soft X-rays with Hinode/XRT and in EUV with TRACE.
Results.The non-thermal footpoints observed with RHESSI spatially and temporally match bright footpoint emission in soft X-rays and EUV. There is the possibility that the non-thermal spectrum extends down to 4 keV. The hard X-ray burst clearly does not follow the expected Neupert effect, with the time integrated hard X-rays not matching the soft X-ray time profile. So, although this is a simple microflare with good X-ray observation coverage it does not fit the standard flare model.

Key words: Sun: corona -- Sun: flares -- Sun: X-rays, gamma rays