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Silva, A.V.R.; Laganá, T.F.; De Castro, C.G.G.; Kaufmann, P.; Costa, J.E.R.; Levato, H.; Rovira, M. "Diffuse component spectra of solar active regions at submillimeter wavelengths" (2005) Solar Physics. 227(2):265-281
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Abstract:

Solar maps at 212 and 405 GHz obtained by the Solar Submillimetric Telescope (SST) show regions of enhanced brightness temperature, which coincide with the location of active regions. A statistical study of the radio emission from these active regions was performed for the first time at such high frequencies during 23 days on June and July 2002, when the atmospheric opacity was low. The brightest regions on the maps were chosen for this study, where the brightness excess observed varies from 3 to 20% above quiet Sun levels (i.e., 200-1000 K) at both wavelengths. Sizes of the regions of enhanced emission calculated at half the maximum value were estimated to be between 2′ and 7′. These sizes agree with observed sizes of active regions at other wavelengths such as Hα and ultraviolet. An important result is that the flux density spectra of all sources increase toward submillimeter frequencies, yielding flux density spectral index with an average value of 2.0. The flux density of the active region sources were complemented with that from maps at 17 and 34 GHz from the Nobeyama Radio Heliograph. The resulting spectra at all four frequencies were fit considering the flux density to be due to thermal bremsstrahlung from the active region. In the calculations, the source radius was assumed to be the mean of the measured values at 212 and 405 K. The effective temperatures of the radio emitting source, assumed homogeneous, obtained from this fit were 0.6-2.9 × 104 K, for source diameters of 2′-7′. © Springer 2005.

Registro:

Documento: Artículo
Título:Diffuse component spectra of solar active regions at submillimeter wavelengths
Autor:Silva, A.V.R.; Laganá, T.F.; De Castro, C.G.G.; Kaufmann, P.; Costa, J.E.R.; Levato, H.; Rovira, M.
Filiación:CRAAM, Universidade Presbiteriana Mackenzie, Rua da Consolação, 896, São Paulo, SP 01302-907, Brazil
Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil
CCS, UNICAMP, Campinas, Sao Paulo, SP 13083-970, Brazil
Instituto Nacional de Pesquisas Espacias, INPE, São José dos Campos, SP, Brazil
Complejo Astronómico El Leoncito, Av. Espana 1512 Sur, San Juan 5400, Argentina
Instituto de Astronomia y Física Del Espacio, Casilla de Correo 67, Sucursal 28, Buenos Aires 1428, Argentina
Año:2005
Volumen:227
Número:2
Página de inicio:265
Página de fin:281
DOI: http://dx.doi.org/10.1007/s11207-005-2787-6
Título revista:Solar Physics
Título revista abreviado:Sol. Phys.
ISSN:00380938
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v227_n2_p265_Silva

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Citas:

---------- APA ----------
Silva, A.V.R., Laganá, T.F., De Castro, C.G.G., Kaufmann, P., Costa, J.E.R., Levato, H. & Rovira, M. (2005) . Diffuse component spectra of solar active regions at submillimeter wavelengths. Solar Physics, 227(2), 265-281.
http://dx.doi.org/10.1007/s11207-005-2787-6
---------- CHICAGO ----------
Silva, A.V.R., Laganá, T.F., De Castro, C.G.G., Kaufmann, P., Costa, J.E.R., Levato, H., et al. "Diffuse component spectra of solar active regions at submillimeter wavelengths" . Solar Physics 227, no. 2 (2005) : 265-281.
http://dx.doi.org/10.1007/s11207-005-2787-6
---------- MLA ----------
Silva, A.V.R., Laganá, T.F., De Castro, C.G.G., Kaufmann, P., Costa, J.E.R., Levato, H., et al. "Diffuse component spectra of solar active regions at submillimeter wavelengths" . Solar Physics, vol. 227, no. 2, 2005, pp. 265-281.
http://dx.doi.org/10.1007/s11207-005-2787-6
---------- VANCOUVER ----------
Silva, A.V.R., Laganá, T.F., De Castro, C.G.G., Kaufmann, P., Costa, J.E.R., Levato, H., et al. Diffuse component spectra of solar active regions at submillimeter wavelengths. Sol. Phys. 2005;227(2):265-281.
http://dx.doi.org/10.1007/s11207-005-2787-6