Search

Your search keyword '"Toribio MC"' showing total 8 results
Start Over Author "Toribio MC" Database OAIster
8 results on '"Toribio MC"'

1. Low-frequency radio absorption in Cassiopeia A

Author

Arias, M, Vink, J, De Gasperin, F, Salas, P, Oonk, JBR, Van Weeren, RJ, Van Amesfoort, AS, Anderson, J, Beck, R, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Ciardi, B, De Geus, E, Deller, A, Van Dijk, PCG, Duscha, S, Eislöffel, J, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Heald, G, Hessels, J, Hörandel, J, Holties, HA, Van Der Horst, AJ, Iacobelli, M, Juette, E, Krankowski, A, Van Leeuwen, J, Mann, G, McKay-Bukowski, D, McKean, JP, Mulder, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pekal, R, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Rothkaehl, H, Schwarz, DJ, Smirnov, O, Soida, M, Steinmetz, M, Tagger, M, Thoudam, S, Toribio, MC, Vocks, C, Van Der Wiel, MHD, Wijers, RAMJ, Wucknitz, O, Zarka, P, Zucca, P, Arias, M, Vink, J, De Gasperin, F, Salas, P, Oonk, JBR, Van Weeren, RJ, Van Amesfoort, AS, Anderson, J, Beck, R, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Ciardi, B, De Geus, E, Deller, A, Van Dijk, PCG, Duscha, S, Eislöffel, J, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Heald, G, Hessels, J, Hörandel, J, Holties, HA, Van Der Horst, AJ, Iacobelli, M, Juette, E, Krankowski, A, Van Leeuwen, J, Mann, G, McKay-Bukowski, D, McKean, JP, Mulder, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pekal, R, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Rothkaehl, H, Schwarz, DJ, Smirnov, O, Soida, M, Steinmetz, M, Tagger, M, Thoudam, S, Toribio, MC, Vocks, C, Van Der Wiel, MHD, Wijers, RAMJ, Wucknitz, O, Zarka, P, and Zucca, P

Abstract

© ESO 2018. Context. Cassiopeia A is one of the best-studied supernova remnants. Its bright radio and X-ray emission is due to shocked ejecta. Cas A is rather unique in that the unshocked ejecta can also be studied: through emission in the infrared, the radio-active decay of 44Ti, and the low-frequency free-free absorption caused by cold ionised gas, which is the topic of this paper. Aims. Free-free absorption processes are affected by the mass, geometry, temperature, and ionisation conditions in the absorbing gas. Observations at the lowest radio frequencies can constrain a combination of these properties. Methods. We used Low Frequency Array (LOFAR) Low Band Antenna observations at 30-77 MHz and Very Large Array (VLA) L-band observations at 1-2 GHz to fit for internal absorption as parametrised by the emission measure. We simultaneously fit multiple UV-matched images with a common resolution of 17″ (this corresponds to 0.25 pc for a source t the distance of Cas A). The ample frequency coverage allows us separate the relative contributions from the absorbing gas, the unabsorbed front of the shell, and the absorbed back of the shell to the emission spectrum. We explored the effects that a temperature lower than the ~100-500 K proposed from infrared observations and a high degree of clumping can have on the derived physical properties of the unshocked material, such as its mass and density. We also compiled integrated radio flux density measurements, fit for the absorption processes that occur in the radio band, and considered their effect on the secular decline of the source. Results. We find a mass in the unshocked ejecta of M = 2.95 ± 0.48 MȮ for an assumed gas temperatureof T = 100 K. This estimate is reduced for colder gas temperatures and, most significantly, if the ejecta are clumped. We measure the reverse shock to have a radius of 114″± 6″ and be centred at 23:23:26, +58:48:54 (J2000). We also find that a decrease in the amount of mass in the unshocked eject

Published
2018

2. Tracking of an electron beam through the solar corona with LOFAR

Author

Mann, G, Breitling, F, Vocks, C, Aurass, H, Steinmetz, M, Strassmeier, KG, Bisi, MM, Fallows, RA, Gallagher, P, Kerdraon, A, Mackinnon, A, Magdalenic, J, Rucker, H, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bîrzan, L, Bonafede, A, Broderick, JW, Brüggen, M, Butcher, HR, Ciardi, B, Corstanje, A, Gasperin, FD, Geus, ED, Deller, A, Duscha, S, Eislöffel, J, Engels, D, Falcke, H, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, J, Gunst, AW, Haarlem, MV, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Hörandel, J, Horneffer, A, Juette, E, Karastergiou, A, Klijn, WFA, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Maat, P, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Rafferty, D, Reich, W, Röttgering, H, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Tagger, M, Tang, Y, Tasse, C, Veen, ST, Thoudam, S, Toribio, MC, Vermeulen, R, Weeren, RJV, Wise, MW, Wucknitz, O, Yatawatta, S, Zarka, P, Zensus, JA, Mann, G, Breitling, F, Vocks, C, Aurass, H, Steinmetz, M, Strassmeier, KG, Bisi, MM, Fallows, RA, Gallagher, P, Kerdraon, A, Mackinnon, A, Magdalenic, J, Rucker, H, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bîrzan, L, Bonafede, A, Broderick, JW, Brüggen, M, Butcher, HR, Ciardi, B, Corstanje, A, Gasperin, FD, Geus, ED, Deller, A, Duscha, S, Eislöffel, J, Engels, D, Falcke, H, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, J, Gunst, AW, Haarlem, MV, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Hörandel, J, Horneffer, A, Juette, E, Karastergiou, A, Klijn, WFA, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Maat, P, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Rafferty, D, Reich, W, Röttgering, H, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Tagger, M, Tang, Y, Tasse, C, Veen, ST, Thoudam, S, Toribio, MC, Vermeulen, R, Weeren, RJV, Wise, MW, Wucknitz, O, Yatawatta, S, Zarka, P, and Zensus, JA

Abstract

© ESO 2018. The Sun's activity leads to bursts of radio emission, among other phenomena. An example is type-III radio bursts. They occur frequently and appear as short-lived structures rapidly drifting from high to low frequencies in dynamic radio spectra. They are usually interpreted as signatures of beams of energetic electrons propagating along coronal magnetic field lines. Here we present novel interferometric LOFAR (LOw Frequency ARray) observations of three solar type-III radio bursts and their reverse bursts with high spectral, spatial, and temporal resolution. They are consistent with a propagation of the radio sources along the coronal magnetic field lines with nonuniform speed. Hence, the type-III radio bursts cannot be generated by a monoenergetic electron beam, but by an ensemble of energetic electrons with a spread distribution in velocity and energy. Additionally, the density profile along the propagation path is derived in the corona. It agrees well with three-fold coronal density model by (1961, ApJ, 133, 983).

Published
2018

3. Low-frequency radio absorption in Cassiopeia A

Author

Arias, M, Vink, J, De Gasperin, F, Salas, P, Oonk, JBR, Van Weeren, RJ, Van Amesfoort, AS, Anderson, J, Beck, R, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Ciardi, B, De Geus, E, Deller, A, Van Dijk, PCG, Duscha, S, Eislöffel, J, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Heald, G, Hessels, J, Hörandel, J, Holties, HA, Van Der Horst, AJ, Iacobelli, M, Juette, E, Krankowski, A, Van Leeuwen, J, Mann, G, McKay-Bukowski, D, McKean, JP, Mulder, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pekal, R, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Rothkaehl, H, Schwarz, DJ, Smirnov, O, Soida, M, Steinmetz, M, Tagger, M, Thoudam, S, Toribio, MC, Vocks, C, Van Der Wiel, MHD, Wijers, RAMJ, Wucknitz, O, Zarka, P, Zucca, P, Arias, M, Vink, J, De Gasperin, F, Salas, P, Oonk, JBR, Van Weeren, RJ, Van Amesfoort, AS, Anderson, J, Beck, R, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Ciardi, B, De Geus, E, Deller, A, Van Dijk, PCG, Duscha, S, Eislöffel, J, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Heald, G, Hessels, J, Hörandel, J, Holties, HA, Van Der Horst, AJ, Iacobelli, M, Juette, E, Krankowski, A, Van Leeuwen, J, Mann, G, McKay-Bukowski, D, McKean, JP, Mulder, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pekal, R, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Rothkaehl, H, Schwarz, DJ, Smirnov, O, Soida, M, Steinmetz, M, Tagger, M, Thoudam, S, Toribio, MC, Vocks, C, Van Der Wiel, MHD, Wijers, RAMJ, Wucknitz, O, Zarka, P, and Zucca, P

Abstract

© ESO 2018. Context. Cassiopeia A is one of the best-studied supernova remnants. Its bright radio and X-ray emission is due to shocked ejecta. Cas A is rather unique in that the unshocked ejecta can also be studied: through emission in the infrared, the radio-active decay of 44Ti, and the low-frequency free-free absorption caused by cold ionised gas, which is the topic of this paper. Aims. Free-free absorption processes are affected by the mass, geometry, temperature, and ionisation conditions in the absorbing gas. Observations at the lowest radio frequencies can constrain a combination of these properties. Methods. We used Low Frequency Array (LOFAR) Low Band Antenna observations at 30-77 MHz and Very Large Array (VLA) L-band observations at 1-2 GHz to fit for internal absorption as parametrised by the emission measure. We simultaneously fit multiple UV-matched images with a common resolution of 17″ (this corresponds to 0.25 pc for a source t the distance of Cas A). The ample frequency coverage allows us separate the relative contributions from the absorbing gas, the unabsorbed front of the shell, and the absorbed back of the shell to the emission spectrum. We explored the effects that a temperature lower than the ~100-500 K proposed from infrared observations and a high degree of clumping can have on the derived physical properties of the unshocked material, such as its mass and density. We also compiled integrated radio flux density measurements, fit for the absorption processes that occur in the radio band, and considered their effect on the secular decline of the source. Results. We find a mass in the unshocked ejecta of M = 2.95 ± 0.48 MȮ for an assumed gas temperatureof T = 100 K. This estimate is reduced for colder gas temperatures and, most significantly, if the ejecta are clumped. We measure the reverse shock to have a radius of 114″± 6″ and be centred at 23:23:26, +58:48:54 (J2000). We also find that a decrease in the amount of mass in the unshocked eject

Published
2018

4. Tracking of an electron beam through the solar corona with LOFAR

Author

Mann, G, Breitling, F, Vocks, C, Aurass, H, Steinmetz, M, Strassmeier, KG, Bisi, MM, Fallows, RA, Gallagher, P, Kerdraon, A, Mackinnon, A, Magdalenic, J, Rucker, H, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bîrzan, L, Bonafede, A, Broderick, JW, Brüggen, M, Butcher, HR, Ciardi, B, Corstanje, A, Gasperin, FD, Geus, ED, Deller, A, Duscha, S, Eislöffel, J, Engels, D, Falcke, H, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, J, Gunst, AW, Haarlem, MV, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Hörandel, J, Horneffer, A, Juette, E, Karastergiou, A, Klijn, WFA, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Maat, P, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Rafferty, D, Reich, W, Röttgering, H, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Tagger, M, Tang, Y, Tasse, C, Veen, ST, Thoudam, S, Toribio, MC, Vermeulen, R, Weeren, RJV, Wise, MW, Wucknitz, O, Yatawatta, S, Zarka, P, Zensus, JA, Mann, G, Breitling, F, Vocks, C, Aurass, H, Steinmetz, M, Strassmeier, KG, Bisi, MM, Fallows, RA, Gallagher, P, Kerdraon, A, Mackinnon, A, Magdalenic, J, Rucker, H, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bîrzan, L, Bonafede, A, Broderick, JW, Brüggen, M, Butcher, HR, Ciardi, B, Corstanje, A, Gasperin, FD, Geus, ED, Deller, A, Duscha, S, Eislöffel, J, Engels, D, Falcke, H, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, J, Gunst, AW, Haarlem, MV, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Hörandel, J, Horneffer, A, Juette, E, Karastergiou, A, Klijn, WFA, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Maat, P, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Rafferty, D, Reich, W, Röttgering, H, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Tagger, M, Tang, Y, Tasse, C, Veen, ST, Thoudam, S, Toribio, MC, Vermeulen, R, Weeren, RJV, Wise, MW, Wucknitz, O, Yatawatta, S, Zarka, P, and Zensus, JA

Abstract

© ESO 2018. The Sun's activity leads to bursts of radio emission, among other phenomena. An example is type-III radio bursts. They occur frequently and appear as short-lived structures rapidly drifting from high to low frequencies in dynamic radio spectra. They are usually interpreted as signatures of beams of energetic electrons propagating along coronal magnetic field lines. Here we present novel interferometric LOFAR (LOw Frequency ARray) observations of three solar type-III radio bursts and their reverse bursts with high spectral, spatial, and temporal resolution. They are consistent with a propagation of the radio sources along the coronal magnetic field lines with nonuniform speed. Hence, the type-III radio bursts cannot be generated by a monoenergetic electron beam, but by an ensemble of energetic electrons with a spread distribution in velocity and energy. Additionally, the density profile along the propagation path is derived in the corona. It agrees well with three-fold coronal density model by (1961, ApJ, 133, 983).

Published
2018

5. The association of a J -burst with a solar jet

Author

Morosan, DE, Gallagher, PT, Fallows, RA, Reid, H, Mann, G, Bisi, MM, Magdalenić, J, Rucker, HO, Thidé, B, Vocks, C, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Bonafede, A, Breitling, F, Broderick, JW, Brüggen, M, Cerrigone, L, Ciardi, B, De Geus, E, Duscha, S, Eislöffel, J, Falcke, H, Garrett, MA, Grießmeier, JM, Gunst, AW, Hoeft, M, Iacobelli, M, Juette, E, Kuper, G, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Reich, W, Schwarz, DJ, Sluman, J, Smirnov, O, Steinmetz, M, Tagger, M, Ter Veen, S, Thoudam, S, Toribio, MC, Vermeulen, R, Van Weeren, RJ, Wucknitz, O, Zarka, P, Morosan, DE, Gallagher, PT, Fallows, RA, Reid, H, Mann, G, Bisi, MM, Magdalenić, J, Rucker, HO, Thidé, B, Vocks, C, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Bonafede, A, Breitling, F, Broderick, JW, Brüggen, M, Cerrigone, L, Ciardi, B, De Geus, E, Duscha, S, Eislöffel, J, Falcke, H, Garrett, MA, Grießmeier, JM, Gunst, AW, Hoeft, M, Iacobelli, M, Juette, E, Kuper, G, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Reich, W, Schwarz, DJ, Sluman, J, Smirnov, O, Steinmetz, M, Tagger, M, Ter Veen, S, Thoudam, S, Toribio, MC, Vermeulen, R, Van Weeren, RJ, Wucknitz, O, and Zarka, P

Abstract

© ESO, 2017. Context. The Sun is an active star that produces large-scale energetic events such as solar flares and coronal mass ejections, and numerous smaller scale events such as solar jets. These events are often associated with accelerated particles that can cause emission at radio wavelengths. The reconfiguration of the solar magnetic field in the corona is believed to be the cause of the majority of solar energetic events and accelerated particles. Aims. Here, we investigate a bright J-burst that was associated with a solar jet and the possible emission mechanism causing these two phenomena. Methods. We used data from the Solar Dynamics Observatory (SDO) to observe a solar jet and radio data from the Low Frequency Array (LOFAR) and the Nançay Radioheliograph (NRH) to observe a J-burst over a broad frequency range (33-173 MHz) on 9 July 2013 at ~11:06 UT. Results. The J-burst showed fundamental and harmonic components and was associated with a solar jet observed at extreme ultraviolet wavelengths with SDO. The solar jet occurred in the northern hemisphere at a time and location coincident with the radio burst and not inside a group of complex active regions in the southern hemisphere. The jet occurred in the negative polarity region of an area of bipolar plage. Newly emerged positive flux in this region appeared to be the trigger of the jet. Conclusions. Magnetic reconnection between the overlying coronal field lines and the newly emerged positive field lines is most likely the cause of the solar jet. Radio imaging provides a clear association between the jet and the J-burst, which shows the path of the accelerated electrons. These electrons travelled from a region in the vicinity of the solar jet along closed magnetic field lines up to the top of a closed magnetic loop at a height of ~360 Mm. Such small-scale complex eruptive events arising from magnetic reconnection could facilitate accelerated electrons to produce continuously the large numbers of Type III

Published
2017

6. The association of a J -burst with a solar jet

Author

Morosan, DE, Gallagher, PT, Fallows, RA, Reid, H, Mann, G, Bisi, MM, Magdalenić, J, Rucker, HO, Thidé, B, Vocks, C, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Bonafede, A, Breitling, F, Broderick, JW, Brüggen, M, Cerrigone, L, Ciardi, B, De Geus, E, Duscha, S, Eislöffel, J, Falcke, H, Garrett, MA, Grießmeier, JM, Gunst, AW, Hoeft, M, Iacobelli, M, Juette, E, Kuper, G, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Reich, W, Schwarz, DJ, Sluman, J, Smirnov, O, Steinmetz, M, Tagger, M, Ter Veen, S, Thoudam, S, Toribio, MC, Vermeulen, R, Van Weeren, RJ, Wucknitz, O, Zarka, P, Morosan, DE, Gallagher, PT, Fallows, RA, Reid, H, Mann, G, Bisi, MM, Magdalenić, J, Rucker, HO, Thidé, B, Vocks, C, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Best, P, Blaauw, R, Bonafede, A, Breitling, F, Broderick, JW, Brüggen, M, Cerrigone, L, Ciardi, B, De Geus, E, Duscha, S, Eislöffel, J, Falcke, H, Garrett, MA, Grießmeier, JM, Gunst, AW, Hoeft, M, Iacobelli, M, Juette, E, Kuper, G, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pizzo, R, Polatidis, AG, Reich, W, Schwarz, DJ, Sluman, J, Smirnov, O, Steinmetz, M, Tagger, M, Ter Veen, S, Thoudam, S, Toribio, MC, Vermeulen, R, Van Weeren, RJ, Wucknitz, O, and Zarka, P

Abstract

© ESO, 2017. Context. The Sun is an active star that produces large-scale energetic events such as solar flares and coronal mass ejections, and numerous smaller scale events such as solar jets. These events are often associated with accelerated particles that can cause emission at radio wavelengths. The reconfiguration of the solar magnetic field in the corona is believed to be the cause of the majority of solar energetic events and accelerated particles. Aims. Here, we investigate a bright J-burst that was associated with a solar jet and the possible emission mechanism causing these two phenomena. Methods. We used data from the Solar Dynamics Observatory (SDO) to observe a solar jet and radio data from the Low Frequency Array (LOFAR) and the Nançay Radioheliograph (NRH) to observe a J-burst over a broad frequency range (33-173 MHz) on 9 July 2013 at ~11:06 UT. Results. The J-burst showed fundamental and harmonic components and was associated with a solar jet observed at extreme ultraviolet wavelengths with SDO. The solar jet occurred in the northern hemisphere at a time and location coincident with the radio burst and not inside a group of complex active regions in the southern hemisphere. The jet occurred in the negative polarity region of an area of bipolar plage. Newly emerged positive flux in this region appeared to be the trigger of the jet. Conclusions. Magnetic reconnection between the overlying coronal field lines and the newly emerged positive field lines is most likely the cause of the solar jet. Radio imaging provides a clear association between the jet and the J-burst, which shows the path of the accelerated electrons. These electrons travelled from a region in the vicinity of the solar jet along closed magnetic field lines up to the top of a closed magnetic loop at a height of ~360 Mm. Such small-scale complex eruptive events arising from magnetic reconnection could facilitate accelerated electrons to produce continuously the large numbers of Type III

Published
2017

7. A large light-mass component of cosmic rays at 1017-1017.5 electronvolts from radio observations

Author

Buitink, S, Corstanje, A, Falcke, H, Hörandel, JR, Huege, T, Nelles, A, Rachen, JP, Rossetto, L, Schellart, P, Scholten, O, Ter Veen, S, Thoudam, S, Trinh, TNG, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bonafede, A, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Carbone, D, Ciardi, B, Conway, JE, De Gasperin, F, De Geus, E, Deller, A, Dettmar, RJ, Van Diepen, G, Duscha, S, Eislöffel, J, Engels, D, Enriquez, JE, Fallows, RA, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Horneffer, A, Iacobelli, M, Intema, H, Juette, E, Karastergiou, A, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Van Leeuwen, J, Loose, GM, Maat, P, Mann, G, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mevius, M, Mulcahy, DD, Munk, H, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pietka, M, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Steinmetz, M, Stewart, A, Swinbank, J, Tagger, M, Tang, Y, Tasse, C, Toribio, MC, Vermeulen, R, Vocks, C, Vogt, C, Van Weeren, RJ, Wijers, RAMJ, Wijnholds, SJ, Wise, MW, Buitink, S, Corstanje, A, Falcke, H, Hörandel, JR, Huege, T, Nelles, A, Rachen, JP, Rossetto, L, Schellart, P, Scholten, O, Ter Veen, S, Thoudam, S, Trinh, TNG, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bonafede, A, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Carbone, D, Ciardi, B, Conway, JE, De Gasperin, F, De Geus, E, Deller, A, Dettmar, RJ, Van Diepen, G, Duscha, S, Eislöffel, J, Engels, D, Enriquez, JE, Fallows, RA, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Horneffer, A, Iacobelli, M, Intema, H, Juette, E, Karastergiou, A, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Van Leeuwen, J, Loose, GM, Maat, P, Mann, G, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mevius, M, Mulcahy, DD, Munk, H, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pietka, M, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Steinmetz, M, Stewart, A, Swinbank, J, Tagger, M, Tang, Y, Tasse, C, Toribio, MC, Vermeulen, R, Vocks, C, Vogt, C, Van Weeren, RJ, Wijers, RAMJ, Wijnholds, SJ, and Wise, MW

Abstract

© 2016 Macmillan Publishers Limited. All rights reserved. Cosmic rays are the highest-energy particles found in nature. Measurements of the mass composition of cosmic rays with energies of 1017-1018 electronvolts are essential to understanding whether they have galactic or extragalactic sources. It has also been proposed that the astrophysical neutrino signal comes from accelerators capable of producing cosmic rays of these energies. Cosmic rays initiate air showers - cascades of secondary particles in the atmosphere - and their masses can be inferred from measurements of the atmospheric depth of the shower maximum (Xmax; the depth of the air shower when it contains the most particles) or of the composition of shower particles reaching the ground. Current measurements have either high uncertainty, or a low duty cycle and a high energy threshold. Radio detection of cosmic rays is a rapidly developing technique for determining Xmax (refs 10, 11) with a duty cycle of, in principle, nearly 100 per cent. The radiation is generated by the separation of relativistic electrons and positrons in the geomagnetic field and a negative charge excess in the shower front. Here we report radio measurements of Xmax with a mean uncertainty of 16 grams per square centimetre for air showers initiated by cosmic rays with energies of 1017-1017.5 electronvolts. This high resolution in Xmax enables us to determine the mass spectrum of the cosmic rays: we find a mixed composition, with a light-mass fraction (protons and helium nuclei) of about 80 per cent. Unless, contrary to current expectations, the extragalactic component of cosmic rays contributes substantially to the total flux below 1017.5 electronvolts, our measurements indicate the existence of an additional galactic component, to account for the light composition that we measured in the 1017-1017.5 electronvolt range.

Published
2016

8. A large light-mass component of cosmic rays at 1017-1017.5 electronvolts from radio observations

Author

Buitink, S, Corstanje, A, Falcke, H, Hörandel, JR, Huege, T, Nelles, A, Rachen, JP, Rossetto, L, Schellart, P, Scholten, O, Ter Veen, S, Thoudam, S, Trinh, TNG, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bonafede, A, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Carbone, D, Ciardi, B, Conway, JE, De Gasperin, F, De Geus, E, Deller, A, Dettmar, RJ, Van Diepen, G, Duscha, S, Eislöffel, J, Engels, D, Enriquez, JE, Fallows, RA, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Horneffer, A, Iacobelli, M, Intema, H, Juette, E, Karastergiou, A, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Van Leeuwen, J, Loose, GM, Maat, P, Mann, G, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mevius, M, Mulcahy, DD, Munk, H, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pietka, M, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Steinmetz, M, Stewart, A, Swinbank, J, Tagger, M, Tang, Y, Tasse, C, Toribio, MC, Vermeulen, R, Vocks, C, Vogt, C, Van Weeren, RJ, Wijers, RAMJ, Wijnholds, SJ, Wise, MW, Buitink, S, Corstanje, A, Falcke, H, Hörandel, JR, Huege, T, Nelles, A, Rachen, JP, Rossetto, L, Schellart, P, Scholten, O, Ter Veen, S, Thoudam, S, Trinh, TNG, Anderson, J, Asgekar, A, Avruch, IM, Bell, ME, Bentum, MJ, Bernardi, G, Best, P, Bonafede, A, Breitling, F, Broderick, JW, Brouw, WN, Brüggen, M, Butcher, HR, Carbone, D, Ciardi, B, Conway, JE, De Gasperin, F, De Geus, E, Deller, A, Dettmar, RJ, Van Diepen, G, Duscha, S, Eislöffel, J, Engels, D, Enriquez, JE, Fallows, RA, Fender, R, Ferrari, C, Frieswijk, W, Garrett, MA, Grießmeier, JM, Gunst, AW, Van Haarlem, MP, Hassall, TE, Heald, G, Hessels, JWT, Hoeft, M, Horneffer, A, Iacobelli, M, Intema, H, Juette, E, Karastergiou, A, Kondratiev, VI, Kramer, M, Kuniyoshi, M, Kuper, G, Van Leeuwen, J, Loose, GM, Maat, P, Mann, G, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mevius, M, Mulcahy, DD, Munk, H, Norden, MJ, Orru, E, Paas, H, Pandey-Pommier, M, Pandey, VN, Pietka, M, Pizzo, R, Polatidis, AG, Reich, W, Röttgering, HJA, Scaife, AMM, Schwarz, DJ, Serylak, M, Sluman, J, Smirnov, O, Stappers, BW, Steinmetz, M, Stewart, A, Swinbank, J, Tagger, M, Tang, Y, Tasse, C, Toribio, MC, Vermeulen, R, Vocks, C, Vogt, C, Van Weeren, RJ, Wijers, RAMJ, Wijnholds, SJ, and Wise, MW

Abstract

© 2016 Macmillan Publishers Limited. All rights reserved. Cosmic rays are the highest-energy particles found in nature. Measurements of the mass composition of cosmic rays with energies of 1017-1018 electronvolts are essential to understanding whether they have galactic or extragalactic sources. It has also been proposed that the astrophysical neutrino signal comes from accelerators capable of producing cosmic rays of these energies. Cosmic rays initiate air showers - cascades of secondary particles in the atmosphere - and their masses can be inferred from measurements of the atmospheric depth of the shower maximum (Xmax; the depth of the air shower when it contains the most particles) or of the composition of shower particles reaching the ground. Current measurements have either high uncertainty, or a low duty cycle and a high energy threshold. Radio detection of cosmic rays is a rapidly developing technique for determining Xmax (refs 10, 11) with a duty cycle of, in principle, nearly 100 per cent. The radiation is generated by the separation of relativistic electrons and positrons in the geomagnetic field and a negative charge excess in the shower front. Here we report radio measurements of Xmax with a mean uncertainty of 16 grams per square centimetre for air showers initiated by cosmic rays with energies of 1017-1017.5 electronvolts. This high resolution in Xmax enables us to determine the mass spectrum of the cosmic rays: we find a mixed composition, with a light-mass fraction (protons and helium nuclei) of about 80 per cent. Unless, contrary to current expectations, the extragalactic component of cosmic rays contributes substantially to the total flux below 1017.5 electronvolts, our measurements indicate the existence of an additional galactic component, to account for the light composition that we measured in the 1017-1017.5 electronvolt range.

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results