First analysis of solar structures in 1.21 mm full-disc ALMA image of the Sun

0494658 - ASÚ 2019 RIV FR eng J - Journal Article
Brajša, R. - Sudar, D. - Benz, A. O. - Skokić, I. - Bárta, Miroslav - de Pontieu, B. - Kim, S. - Kobelski, A. - Kuhar, M. - Shimojo, M. - Wedemeyer, S. - White, S.M. - Yagoubov, P. - Yan, Y.
First analysis of solar structures in 1.21 mm full-disc ALMA image of the Sun.
Astronomy & Astrophysics. Roč. 613, May (2018), č. článku A17. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA MŠMT(CZ) LM2015067
EU Projects: European Commission(XE) 312495 - SOLARNET
Grant - others:European Commission - EC(XE) 682462
Program: H2020-EU.1.1.
Institutional support: RVO:67985815
Keywords : Sun * radio radiation * chromosphere
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.209, year: 2018

The first aim of the present work is to identify different structures in the solar atmosphere seen in the optical, infrared, and EUV parts of the spectrum (quiet Sun, active regions, prominences on the disc, magnetic inversion lines, coronal holes and coronal bright points) in a full-disc solar ALMA image. The second aim is to measure the intensities (brightness temperatures) of those structures and to compare them with the corresponding quiet Sun level. A full-disc solar image at 1.21 mm obtained on December 18, 2015, during a CSV-EOC campaign with ALMA is calibrated and compared with full-disc solar images from the same day in H alpha line, in He I 1083 nm line core, and with various SDO images (AIA at 170 nm, 30.4 nm, 21.1 nm, 19.3 nm, and 17.1 nm and HMI magnetogram). The brightness temperatures of various structures are determined by averaging over corresponding regions of interest in the calibrated ALMA image. Positions of the quiet Sun, active regions, prominences on the disc, magnetic inversion lines, coronal holes and coronal bright points are identified in the ALMA image. At the wavelength of 1.21 mm, active regions appear as bright areas (but sunspots are dark), while prominences on the disc and coronal holes are not discernible from the quiet Sun background, despite having slightly less intensity than surrounding quiet Sun regions. Magnetic inversion lines appear as large, elongated dark structures and coronal bright points correspond to ALMA bright points.
Permanent Link: http://hdl.handle.net/11104/0288298