Abstract
The Neupert effect is the empirical observation that the temporal evolution of non-thermal emission (e.g. hard X-rays) is frequently proportional to the temporal derivative of the thermal emission flux (soft X-rays), or vice versa, that time-integrated non-thermal flux is proportional to thermal flux. We analyzed the GOES M2.2 event SOL2011-02-14T17:25, and we found that the 212 GHz emission plays quite well the role of the thermal component of the Neupert effect. We show that the maximum of the hard X-ray flux for energies above 50 keV is coincident in time with the temporal derivative of the 212 GHz flux, within the uncertainties. The microwave flux density at 15.4 GHz, produced by optically thin gyrosynchrotron mechanism, and hard-X rays above 25 keV mark the typical impulsive phase, and they have similar temporal evolution. On the other hand, the 212 GHz emission is delayed by about 25 seconds with respect to the microwave and hard X-ray peak. We argue that this delay cannot be explained by magnetic trapping of non-thermal electrons. With all of the observational evidence, we suggest that the 212 GHz emission is produced by thermal bremsstrahlung, initially in the chromosphere, and shifting to optically thin emission from the hot coronal loops at the end of the gradual phase.
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References
Allred, J.C., Kowalski, A.F., Carlsson, M.: 2015, A unified computational model for solar and stellar flares. Astrophys. J.809, 104. DOI . ADS .
Antonucci, E., Gabriel, A.H., Dennis, B.R.: 1984, The energetics of chromospheric evaporation in solar flares. Astrophys. J.287, 917. DOI . ADS .
Bastian, T.S., Benz, A.O., Gary, D.E.: 1998, Radio emission from solar flares. Annu. Rev. Astron. Astrophys.36, 131. ADS .
Carlsson, M.: 1998, Radiative transfer and radiation hydrodynamics. In: Vial, J.C., Bocchialini, K., Boumier, P. (eds.) Space Solar Physics: Theoretical and Observational Issues in the Context of the SOHO Mission; Proc. of a Summer School, Lecture Notes in Physics507, Springer, New York, 163. DOI . ADS .
Carlsson, M., Stein, R.F.: 1995, Does a nonmagnetic solar chromosphere exist? Astrophys. J. Lett.440, L29. DOI . ADS .
Costa, J.E.R., Silva, A.V.R., Lüdi, A., Magun, A.: 2002, Beam profile determination by tomography of solar scans. Astron. Astrophys.387, 1153. ADS .
Cristiani, G., Martinez, G., Mandrini, C.H., Giménez de Castro, C.G., da Silva, C.W., Rovira, M.G., Kaufmann, P.: 2007, Spatial characterization of a flare using radio observations and magnetic field topology. Solar Phys.240, 271. DOI .
Dulk, G.A.: 1985, Radio emission from the Sun and stars. Annu. Rev. Astron. Astrophys.23, 169. ADS .
Fleishman, G.D., Kontar, E.P.: 2010, Sub-Thz radiation mechanisms in solar flares. Astrophys. J. Lett.709, L127. DOI . ADS .
Frost, K.J.: 1964, Comments on high energy X-ray bursts observed by OSO I. NASASP-50, 139. ADS .
Giménez de Castro, C.G., Raulin, J.-P., Makhmutov, V.S., Kaufmann, P., Costa, J.E.R.: 1999, Instantaneous positions of microwave solar bursts: Properties and validity of the multiple beam observations. Astron. Astrophys. Suppl. Ser.140, 373. ADS .
Giménez de Castro, C.G., Trottet, G., Silva-Valio, A., Krucker, S., Costa, J.E.R., Kaufmann, P., Correia, E., Levato, H.: 2009, Submillimeter and X-ray observations of an X class flare. Astron. Astrophys.507, 433. DOI . ADS .
Guidice, D.A., Cliver, E.W., Barron, W.R., Kahler, S.: 1981, The air force RSTN system. Bull. Am. Astron. Soc.13, 553. ADS .
Heinzel, P., Avrett, E.H.: 2012, Optical-to-radio continua in solar flares. Solar Phys.277, 31. DOI . ADS .
Herrmann, R., Magun, A., Costa, J.E.R., Correia, E., Kaufmann, P.: 1992, A multibeam antenna for solar mm-wave burst observations with high spatial and temporal resolution. Solar Phys.142, 157. ADS .
Hudson, H.S.: 1991, Differential emission-measure variations and the “Neupert effect”. Bull. Am. Astron. Soc.23, 1064. ADS .
Hudson, H.S., Ohki, K.: 1972, Soft X-ray and microwave observations of hot regions in solar flares. Solar Phys.23, 155. DOI . ADS .
Kašparová, J., Heinzel, P., Karlický, M., Moravec, Z., Varady, M.: 2009, Far-IR and radio thermal continua in solar flares. Cent. Eur. Astrophys. Bull.33, 309. ADS .
Kaufmann, P., Raulin, J.-P.: 2006, Can microbunch instability on solar flare accelerated electron beams account for bright broadband coherent synchrotron microwaves? Phys. Plasmas13, 701. DOI . ADS .
Kaufmann, P., Levato, H., Cassiano, M.M., Correia, E., Costa, J.E.R., Giménez de Castro, C.G., Godoy, R., Kingsley, R.K., Kingsley, J.S., Kudaka, A.S., Marcon, R., Martin, R., Marun, A., Melo, A.M., Pereyra, P., Raulin, J.-P., Rose, T., Silva Valio, A., Walber, A., Wallace, P., Yakubovich, A., Zakia, M.B.: 2008, New telescopes for ground-based solar observations at submillimeter and mid-infrared. In: Soc. Photo-Opt. Instrum. Eng. (SPIE)CS-7012. DOI . ADS .
Kaufmann, P., White, S.M., Freeland, S.L., Marcon, R., Fernandes, L.O.T., Kudaka, A.S., de Souza, R.V., Aballay, J.L., Fernandez, G., Godoy, R., Marun, A., Valio, A., Raulin, J.-P., Giménez de Castro, C.G.: 2013, A bright impulsive solar burst detected at 30 THz. Astrophys. J.768, 134. DOI . ADS .
Kaufmann, P., Abrantes, A., Bortolucci, E., Caspi, A., Fernandes, L.O.T., Kropotov, G., Kudaka, A., Laurent, G.T., Machado, N., Marcon, R., Marun, A., Nicolaev, V., Hidalgo Ramirez, R.F., Raulin, J.-P., Saint-Hilaire, P., Shih, A., Silva, C., Timofeevsky, A.: 2016, Solar observations at THz frequencies on board of a trans-Antartic stratospheric balloon flight. In: AAS/Solar Phys. Div. Meet.47, 6.11. ADS .
Kleint, L., Heinzel, P., Judge, P., Krucker, S.: 2016, Continuum enhancements in the ultraviolet, the visible and the infrared during the X1 flare on 2014 March 29. Astrophys. J.816, 88. DOI . ADS .
Krucker, S., Giménez de Castro, C.G., Hudson, H.S., Trottet, G., Bastian, T.S., Hales, A.S., Kašparová, J., Klein, K.-L., Kretzschmar, M., Lüthi, T., Mackinnon, A., Pohjolainen, S., White, S.M.: 2013, Solar flares at submillimeter wavelengths. Astron. Astrophys. Rev.21, 58. DOI . ADS .
Lüthi, T., Lüdi, A., Magun, A.: 2004, Determination of the location and effective angular size of solar flares with a 210 GHz multibeam radiometer. Astron. Astrophys.420, 361. ADS .
Lüthi, T., Magun, A., Miller, M.: 2004, First observation of a solar X-class flare in the submillimeter range with KOSMA. Astron. Astrophys.415, 1123. ADS .
McAteer, R.T.J., Bloomfield, D.S.: 2013, The bursty nature of solar flare X-ray emission. II. The Neupert effect. Astrophys. J.776, 66. DOI . ADS .
Meegan, C., Lichti, G., Bhat, P.N., Bissaldi, E., Briggs, M.S., Connaughton, V., Diehl, R., Fishman, G., Greiner, J., Hoover, A.S., van der Horst, A.J., von Kienlin, A., Kippen, R.M., Kouveliotou, C., McBreen, S., Paciesas, W.S., Preece, R., Steinle, H., Wallace, M.S., Wilson, R.B., Wilson-Hodge, C.: 2009, The Fermi Gamma-ray Burst Monitor. Astrophys. J.702, 791. DOI . ADS .
Neupert, W.M.: 1968, Comparison of solar X-ray line emission with microwave emission during flares. Astrophys. J. Lett.153, L59. DOI . ADS .
Penn, M., Krucker, S., Hudson, H., Jhabvala, M., Jennings, D., Lunsford, A., Kaufmann, P.: 2016, Spectral and imaging observations of a white-light solar flare in the mid-infrared. Astrophys. J. Lett.819, L30. DOI . ADS .
Pick, M., Vilmer, N.: 2008, Sixty-five years of solar radioastronomy: Flares, coronal mass ejections and Sun Earth connection. Astron. Astrophys. Rev.16, 6. DOI . ADS .
Ramaty, R., Schwartz, R.A., Enome, S., Nakajima, H.: 1994, Gamma-ray and millimeter-wave emissions from the 1991 June X-class solar flares. Astrophys. J.436, 941. ADS .
Selhorst, C.L., Silva, A.V.R., Costa, J.E.R.: 2005, Solar atmospheric model with spicules applied to radio observation. Astron. Astrophys.433, 365. DOI . ADS .
Silva, A.V.R., Laganá, T.F., Gimenez Castro, C.G., Kaufmann, P., Costa, J.E.R., Levato, H., Rovira, M.: 2005, Diffuse component spectra of solar active regions at submillimeter wavelengths. Solar Phys.227, 265. DOI . ADS .
Simões, P.J.A., Kerr, G.S., Fletcher, L., Hudson, H.S., Giménez de Castro, C.G., Penn, M.: 2017, Formation of the thermal infrared continuum in solar flares. Astron. Astrophys.605, A125. DOI . ADS .
Simões, P.J.A., Reid, H.A.S., Milligan, R.O., Fletcher, L.: 2019, The spectral content of SDO/AIA 1600 and 1700 Å filters from flare and plage observations. Astrophys. J.870(2), 114. DOI . ADS .
Trottet, G., Rolli, E., Magun, A., Barat, C., Kuznetsov, A., Sunyaev, R., Terekhov, O.: 2000, The fast and slow \(\mbox{H}\upalpha\) chromospheric responses to non-thermal particles produced during the 1991 March 13 hard X-ray/gamma-ray flare at \({\sim}\,08~\mbox{UTC}\). Astron. Astrophys.356, 1067. ADS .
Trottet, G., Raulin, J.-P., Kaufmann, P., Siarkowski, M., Klein, K.-L., Gary, D.E.: 2002, First detection of the impulsive and extended phases of a solar radio burst above 200 GHz. Astron. Astrophys.381, 694. ADS .
Trottet, G., Raulin, J.-P., Giménez de Castro, C.G., Lüthi, T., Caspi, A., Mandrini, C., Luoni, M.L., Kaufmann, P.: 2011, Origin of the submillimeter radio emission during the time-extended phase of a solar flare. Solar Phys.273(2), 340. DOI .
Trottet, G., Raulin, J.-P., Mackinnon, A., Giménez de Castro, G., Simões, P.J.A., Cabezas, D., de La Luz, V., Luoni, M., Kaufmann, P.: 2015, Origin of the 30 THz emission detected during the solar flare on 2012 March 13 at 17:20 UT. Solar Phys.290, 2809. DOI . ADS .
Tsap, Y.T., Smirnova, V.V., Morgachev, A.S., Motorina, G.G., Kontar, E.P., Nagnibeda, V.G., Strekalova, P.V.: 2016, On the origin of 140 GHz emission from the 4 July 2012 solar flare. Adv. Space Res.57, 1449. DOI . ADS .
Vernazza, J.E., Avrett, E.H., Loeser, R.: 1981, Structure of the solar chromosphere. III – Models of the EUV brightness components of the quiet-sun. Astrophys. J. Suppl. Ser.45, 635. DOI . ADS .
Veronig, A., Vršnak, B., Dennis, B.R., Temmer, M., Hanslmeier, A., Magdalenić, J.: 2002a, Investigation of the Neupert effect in solar flares. I. Statistical properties and the evaporation model. Astron. Astrophys.392, 699. DOI . ADS .
Veronig, A., Vršnak, B., Temmer, M., Hanslmeier, A.: 2002b, Relative timing of solar flares observed at different wavelengths. Solar Phys.208, 297. DOI . ADS .
Veronig, A.M., Brown, J.C., Dennis, B.R., Schwartz, R.A., Sui, L., Tolbert, A.K.: 2005, Physics of the Neupert effect: Estimates of the effects of source energy, mass transport, and geometry using RHESSI and GOES data. Astrophys. J.621, 482. DOI . ADS .
Wedemeyer, S., Bastian, T., Brajša, R., Hudson, H., Fleishman, G., Loukitcheva, M., Fleck, B., Kontar, E.P., De Pontieu, B., Yagoubov, P., Tiwari, S.K., Soler, R., Black, J.H., Antolin, P., Scullion, E., Gunár, S., Labrosse, N., Ludwig, H.-G., Benz, A.O., White, S.M., Hauschildt, P., Doyle, J.G., Nakariakov, V.M., Ayres, T., Heinzel, P., Karlicky, M., Van Doorsselaere, T., Gary, D., Alissandrakis, C.E., Nindos, A., Solanki, S.K., Rouppe van der Voort, L., Shimojo, M., Kato, Y., Zaqarashvili, T., Perez, E., Selhorst, C.L., Barta, M.: 2016, Solar science with the Atacama Large Millimeter/Submillimeter Array – A new view of our Sun. Space Sci. Rev.200, 1. DOI . ADS .
White, W.A.: 1964, Solar X rays: A comparison with microwave radiation. NASASP-50, 131. ADS .
Acknowledgments
The authors are grateful to Hugh Hudson for his enlightening comments about the Neupert effect and its history. J.F. Valle Silva acknowledges FAPESP for the support during his PhD Thesis (grant 2012/1619-9) and CAPES for the Postdoctoral PNPD contract. G. Giménez de Castro and J.-P. Raulin acknowledge CNPq (contracts 305203/2016-9 and 312066/2016-3). The research leading to these results has received funding from the European Community’s Seventh Framework Program (FP7/2007-2013) under grant agreement no. 606862 (F-CHROMA), CAPES grant 88881.310386/2018-01, FAPESP grant 2013/24155-3 and the US Air Force Office for Scientific Research (AFOSR) grant FA9550-16-1-0072. AIA data are courtesy of NASA/SDO and the AIA science team. This work is based on data acquired at Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juán.
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Valle Silva, J.F., Giménez de Castro, C.G., Simões, P.J.A. et al. Submillimeter Radiation as the Thermal Component of the Neupert Effect. Sol Phys 294, 150 (2019). https://doi.org/10.1007/s11207-019-1542-3
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DOI: https://doi.org/10.1007/s11207-019-1542-3