Letter to the Editor

Line broadening of EUV lines across the Solar limb: A spicule contribution?

¹ Armagh Observatory, College Hill, Armagh, BT61 9DG, N. Ireland e-mail: jgd@arm.ac.uk,
² Sect. of Astrophysics, Astronomy and Mechanics, Dept. of Physics, Univ. of Athens, Athens 15783, Greece
³ School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, PR China
⁴ Max-Planck-Institut für Sonnensystemforschung (Former Max-Planck-Institut für Aeronomie.) , Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany
⁵ Department of Solar Physics, Royal Observatory of Belgium, Av. Circulaire 3, 1180 Bruxelles, Belgium

Received: 20 December 2004
Accepted: 28 December 2004

Abstract

Spectral lines formed in the solar transition region show an increase in the line width, peaking at ≈10 000 km above the limb. Looking at a region off-limb with no obvious spicules, the non-spicule region has a significantly smaller line width above 6000 km compared those taken in a spicule region. We suggest that this increase in line broadening is not due to small scale random motions but rather to unresolved line shifts due to spicules and/or macro-spicules activity.