Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum

Aims. The present solar cycle is particular in many aspects: it had a delayed rising phase, it is the weakest of the last 100 yrs, and it presents two peaks separated by more than one year. To understand the impact of these characteristics on the solar chromosphere and coronal dynamics, images from...

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Autores principales:	Oliveira E Silva, A.J., Selhorst, C.L., Simões, P.J.A., Giménez De Castro, C.G.
Formato:	JOUR
Materias:	Sun: corona Sun: general Sun: radio radiation Sun: transition region Sun: UV radiation Extreme ultraviolet lithography Solar energy Upper atmosphere Sun : corona Sun:transition region Sun:UV radiation Graphic methods
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00046361_v592_n_p_OliveiraESilva
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_00046361_v592_n_p_OliveiraESilva2023-10-03T14:00:59Z Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum Oliveira E Silva, A.J. Selhorst, C.L. Simões, P.J.A. Giménez De Castro, C.G. Sun: corona Sun: general Sun: radio radiation Sun: transition region Sun: UV radiation Extreme ultraviolet lithography Solar energy Upper atmosphere Sun : corona Sun: general Sun: radio radiation Sun:transition region Sun:UV radiation Graphic methods Aims. The present solar cycle is particular in many aspects: it had a delayed rising phase, it is the weakest of the last 100 yrs, and it presents two peaks separated by more than one year. To understand the impact of these characteristics on the solar chromosphere and coronal dynamics, images from a wide wavelength range are needed. In this work we use the 17 GHz radio continuum, which is formed in the upper chromosphere and the extreme ultraviolet (EUV) lines 304 and 171 Å, that come from the transition region (He II, T ∼ 6-8 × 104 K) and the corona (Fe IX, X, T ∼ 106 K), respectively.We extend upon a previous similar analysis, and compare the mean equatorial and polar brightening behavior at radio and EUV wavelengths during the maximum of the present solar cycle, covering the period between 2010 and 2015. Methods. We analyze daily images at 304 and 171 Å obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The 17 GHz maps were obtained by the Nobeyama Radioheliograph (NoRH). To construct synoptic limb charts, we calculated the mean emission of delimited limb areas with 100'' wide and angular separation of 5°. Results. At the equatorial region, the results show a hemispheric asymmetry of the solar activity. The northern hemisphere dominance is coincident with the first sunspot number peak, whereas the second peak occurs concurrently with the increase in the activity at the south. The polar emission reflects the presence of coronal holes at both EUV wavelengths, moreover, the 17 GHz polar brightenings can be associated with the coronal holes. Until 2013, both EUV coronal holes and radio polar brightenings were more predominant at the south pole.Since then they have not been apparent in the north, but thus appear in the beginning of 2015 in the south as observed in the synoptic charts. Conclusions. This work strengthens the association between coronal holes and the 17 GHz polar brightenings as it is evident in the synoptic limb charts in agreement with previous case study papers. The enhancement of the radio brightness in coronal holes is explained by the presence of bright patches closely associated with the presence of intense unipolar magnetic fields. However, observations with better spatial resolution and also at different radio wavelengths will be necessary to fully understand the physical mechanisms that link these features. © ESO, 2016. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00046361_v592_n_p_OliveiraESilva
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Sun: corona Sun: general Sun: radio radiation Sun: transition region Sun: UV radiation Extreme ultraviolet lithography Solar energy Upper atmosphere Sun : corona Sun: general Sun: radio radiation Sun:transition region Sun:UV radiation Graphic methods
spellingShingle	Sun: corona Sun: general Sun: radio radiation Sun: transition region Sun: UV radiation Extreme ultraviolet lithography Solar energy Upper atmosphere Sun : corona Sun: general Sun: radio radiation Sun:transition region Sun:UV radiation Graphic methods Oliveira E Silva, A.J. Selhorst, C.L. Simões, P.J.A. Giménez De Castro, C.G. Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
topic_facet	Sun: corona Sun: general Sun: radio radiation Sun: transition region Sun: UV radiation Extreme ultraviolet lithography Solar energy Upper atmosphere Sun : corona Sun: general Sun: radio radiation Sun:transition region Sun:UV radiation Graphic methods
description	Aims. The present solar cycle is particular in many aspects: it had a delayed rising phase, it is the weakest of the last 100 yrs, and it presents two peaks separated by more than one year. To understand the impact of these characteristics on the solar chromosphere and coronal dynamics, images from a wide wavelength range are needed. In this work we use the 17 GHz radio continuum, which is formed in the upper chromosphere and the extreme ultraviolet (EUV) lines 304 and 171 Å, that come from the transition region (He II, T ∼ 6-8 × 104 K) and the corona (Fe IX, X, T ∼ 106 K), respectively.We extend upon a previous similar analysis, and compare the mean equatorial and polar brightening behavior at radio and EUV wavelengths during the maximum of the present solar cycle, covering the period between 2010 and 2015. Methods. We analyze daily images at 304 and 171 Å obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The 17 GHz maps were obtained by the Nobeyama Radioheliograph (NoRH). To construct synoptic limb charts, we calculated the mean emission of delimited limb areas with 100'' wide and angular separation of 5°. Results. At the equatorial region, the results show a hemispheric asymmetry of the solar activity. The northern hemisphere dominance is coincident with the first sunspot number peak, whereas the second peak occurs concurrently with the increase in the activity at the south. The polar emission reflects the presence of coronal holes at both EUV wavelengths, moreover, the 17 GHz polar brightenings can be associated with the coronal holes. Until 2013, both EUV coronal holes and radio polar brightenings were more predominant at the south pole.Since then they have not been apparent in the north, but thus appear in the beginning of 2015 in the south as observed in the synoptic charts. Conclusions. This work strengthens the association between coronal holes and the 17 GHz polar brightenings as it is evident in the synoptic limb charts in agreement with previous case study papers. The enhancement of the radio brightness in coronal holes is explained by the presence of bright patches closely associated with the presence of intense unipolar magnetic fields. However, observations with better spatial resolution and also at different radio wavelengths will be necessary to fully understand the physical mechanisms that link these features. © ESO, 2016.
format	JOUR
author	Oliveira E Silva, A.J. Selhorst, C.L. Simões, P.J.A. Giménez De Castro, C.G.
author_facet	Oliveira E Silva, A.J. Selhorst, C.L. Simões, P.J.A. Giménez De Castro, C.G.
author_sort	Oliveira E Silva, A.J.
title	Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
title_short	Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
title_full	Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
title_fullStr	Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
title_full_unstemmed	Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
title_sort	comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum
url	http://hdl.handle.net/20.500.12110/paper_00046361_v592_n_p_OliveiraESilva
work_keys_str_mv	AT oliveiraesilvaaj comparisonofsolarradioandextremeultravioletsynopticlimbchartsduringthepresentsolarmaximum AT selhorstcl comparisonofsolarradioandextremeultravioletsynopticlimbchartsduringthepresentsolarmaximum AT simoespja comparisonofsolarradioandextremeultravioletsynopticlimbchartsduringthepresentsolarmaximum AT gimenezdecastrocg comparisonofsolarradioandextremeultravioletsynopticlimbchartsduringthepresentsolarmaximum
_version_	1782026533859229696

Comparison of solar radio and extreme ultraviolet synoptic limb charts during the present solar maximum

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