Suppression of Hydrogen Emission in an X-class White-light Solar Flare

0479466 - ASÚ 2018 RIV US eng J - Článek v odborném periodiku
Procházka, O. - Milligan, R.O. - Allred, J.C. - Kowalski, A.F. - Kotrč, Pavel - Mathioudakis, M.
Suppression of Hydrogen Emission in an X-class White-light Solar Flare.
Astrophysical Journal. Roč. 837, č. 1 (2017), 46/1-46/9. ISSN 0004-637X. E-ISSN 1538-4357
Grant CEP: GA ČR(CZ) GA16-18495S
Grant ostatní: EC(XE) 606862
Program: FP7
Institucionální podpora: RVO:67985815
Klíčová slova: Sun * atmosphere * flares
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 5.551, rok: 2017

We present unique NUV observations of a well-observed X-class flare from NOAA 12087 obtained at the Ondrejov Observatory. The flare shows a strong white-light continuum but no detectable emission in the higher Balmer and Lyman lines. Reuven Ramaty High-Energy Solar Spectroscopic Imager and Fermi observations indicate an extremely hard X-ray spectrum and gamma-ray emission. We use the RADYN radiative hydrodynamic code to perform two types of simulations: one where an energy of 3 x 10(11) erg cm(-2) s(-1) is deposited by an electron beam with a spectral index of approximate to 3, and a second where the same energy is applied directly to the photosphere. The combination of observations and simulations allows us to conclude that the white-light emission and the suppression or complete lack of hydrogen emission lines is best explained by a model where the dominant energy deposition layer is located in the lower layers of the solar atmosphere, rather than the chromosphere.
Trvalý link: http://hdl.handle.net/11104/0275460