| Full text | |
| Author(s): |
Gimenez de Castro, C. Guillermo
[1, 2]
;
Pereira, Andre L. G.
[2]
;
Valle Silva, J. Fernando
[2]
;
Selhorst, Caius L.
[3]
;
Mandrini, Cristina H.
[1, 4]
;
Cristiani, German D.
[1, 4]
;
Raulin, Jean-Pierre
[2]
;
Valio, Adriana
[2]
Total Authors: 8
|
| Affiliation: | [1] CONICET UBA, Inst Astron & Fis Espacio, Buenos Aires, DF - Argentina
[2] Ctr Radio Astron & Astrofis Mackenzie, Rua Consolacao 896, BR-01302907 Sao Paulo, SP - Brazil
[3] Univ Cidade Sao Paulo, Univ Cruzeiro Sul, Nucleo Astrofis, Sao Paulo, SP - Brazil
[4] Univ Buenos Aires, Fac Ciencias Exactas & Nat, RA-1428 Buenos Aires, DF - Argentina
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 902, n. 2 OCT 2020. |
| Web of Science Citations: | 0 |
| Abstract | |
We report the temporal evolution of the excess brightness temperature Delta T-b above solar active regions (ARs) observed with the Solar Submillimeter Telescope (SST) at 212 (lambda = 1.4 mm) and 405 GHz (lambda = 0.7 mm) during Cycles 23 and 24. Comparison with the sunspot number (SSN) yields a Pearson's correlation coefficient R = 0.88 and 0.74 for 212 and 405 GHz, respectively. Moreover, when only Cycle 24 is taken into account the correlation coefficients go to 0.93 and 0.81 for each frequency. We derive the spectral index alpha between SST frequencies and find a slight anticorrelation with the SSN (R = -0.25); however, since the amplitude of the variation is lower than the standard deviation we cannot draw a definite conclusion. Indeed, alpha remains almost constant within the uncertainties with a median value of 0 characteristic of an optically thick thermal source. Since the origin of the AR submillimeter radiation is thermal continuum produced at chromospheric heights, the strong correlation between Delta T-b and the magnetic cycle evolution could be related to the available free magnetic energy to be released in reconnection events. (AU) | |
| FAPESP's process: | 13/24155-3 - Solar flare diagnostic in an unprecedented frequency range from microwaves to THz frequencies: challenges for interpretation (flat) |
| Grantee: | Carlos Guillermo Giménez de Castro |
| Support Opportunities: | Research Projects - Thematic Grants |