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2. Study of the variable broadband emission of Markarian 501 during the most extreme Swift X-ray activity

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Babic, A. (A.), Banerjee, B. (B.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Doro, M. (M.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), de Oliveira Fraga, B. M. (B. Machado), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Garcia, J. R. (J. R.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Arbet-Engels, A. (A.), Baack, D. (D.), Balbo, M. (M.), Biland, A. (A.), Blank, M. (M.), Bretz, T. (T.), Bruegge, K. (K.), Bulinski, M. (M.), Buss, J. (J.), Doerr, M. (M.), Dorner, D. (D.), Einecke, S. (S.), Elsaesser, D. (D.), Hildebrand, D. (D.), Linhoff, L. (L.), Mannheim, K. (K.), Mueller, S. (S.), Neise, D. (D.), Neronov, A. (A.), Noethe, M. (M.), Paravac, A. (A.), Rhode, W. (W.), Schleicher, B. (B.), Schulz, F. (F.), Sedlaczek, K. (K.), Shukla, A. (A.), Sliusar, V. (V), von Willert, E. (E.), Walter, R. (R.), Wendel, C. (C.), Tramacere, A. (A.), Lien, A. (A.), Perri, M. (M.), Verrecchia, F. (F.), Armas Padilla, M. (M.), Leto, C. (C.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Tammi, J. (J.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Babic, A. (A.), Banerjee, B. (B.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Doro, M. (M.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), de Oliveira Fraga, B. M. (B. Machado), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Garcia, J. R. (J. R.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Arbet-Engels, A. (A.), Baack, D. (D.), Balbo, M. (M.), Biland, A. (A.), Blank, M. (M.), Bretz, T. (T.), Bruegge, K. (K.), Bulinski, M. (M.), Buss, J. (J.), Doerr, M. (M.), Dorner, D. (D.), Einecke, S. (S.), Elsaesser, D. (D.), Hildebrand, D. (D.), Linhoff, L. (L.), Mannheim, K. (K.), Mueller, S. (S.), Neise, D. (D.), Neronov, A. (A.), Noethe, M. (M.), Paravac, A. (A.), Rhode, W. (W.), Schleicher, B. (B.), Schulz, F. (F.), Sedlaczek, K. (K.), Shukla, A. (A.), Sliusar, V. (V), von Willert, E. (E.), Walter, R. (R.), Wendel, C. (C.), Tramacere, A. (A.), Lien, A. (A.), Perri, M. (M.), Verrecchia, F. (F.), Armas Padilla, M. (M.), Leto, C. (C.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), and Tammi, J. (J.)

Abstract

Context: Markarian 501 (Mrk 501) is a very high-energy (VHE) gamma-ray blazar located at z = 0.034, which is regularly monitored by a wide range of multi-wavelength instruments, from radio to VHE gamma rays. During a period of almost two weeks in July 2014, the highest X-ray activity of Mrk 501 was observed in ∼14 years of operation of the Neil Gehrels Swift Gamma-ray Burst Observatory. Aims: We characterize the broadband variability of Mrk 501 from radio to VHE gamma rays during the most extreme X-ray activity measured in the last 14 years, and evaluate whether it can be interpreted within theoretical scenarios widely used to explain the broadband emission from blazars. Methods: The emission of Mrk 501 was measured at radio with Metsähovi, at optical–UV with KVA and Swift/UVOT, at X-ray with Swift/XRT and Swift/BAT, at gamma ray with Fermi-LAT, and at VHE gamma rays with the FACT and MAGIC telescopes. The multi-band variability and correlations were quantified, and the broadband spectral energy distributions (SEDs) were compared with predictions from theoretical models. Results: The VHE emission of Mrk 501 was found to be elevated during the X-ray outburst, with a gamma-ray flux above 0.15 TeV varying from ∼0.5 to ∼2 times the Crab nebula flux. The X-ray and VHE emission both varied on timescales of 1 day and were found to be correlated. We measured a general increase in the fractional variability with energy, with the VHE variability being twice as large as the X-ray variability. The temporal evolution of the most prominent and variable segments of the SED, characterized on a day-by-day basis from 2014 July 16 to 2014 July 31, is described with a one-zone synchrotron self-Compton model with variations in the break energy of the electron energy distribution (EED), and with some adjustments in the magnetic field strength and spectral shape of the EED. These results suggest that the main flux variations during this extreme X-ray outburst are produced by the

Published
2020

3. No Fukushima Dai-ichi derived plutonium signal in marine sediments collected 1.5-57km from the reactors

Author

Wendel, C. C. S., Lind, O. C., Fifield, L. K., Tims, S. G., Salbu, B., Oughton, D. H., Wendel, C. C. S., Lind, O. C., Fifield, L. K., Tims, S. G., Salbu, B., and Oughton, D. H.

Abstract

Based on AMS analysis, it is shown that no Pu signals from the Fukushima accident could be discerned in marine sediments collected 1.5-57km away from the Fukushima Da-ichi power plant (FDNPP), which were clearly influenced by accident-derived radiocesium. The 240Pu/239Pu atom ratios (0.21-0.28) were significantly higher than terrestrial global fallout (0.182 ± 0.005), but still in agreement with pre-FDNPP accident baseline data for Pu in near coastal seawaters influenced by global fallout and long-range transport of Pu from the Pacific Proving Grounds.

Published
2017

4. First multi-wavelength campaign on the gamma-ray-loud active galaxy IC 310

Author

Ahnen, M. L. (M. L.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Arcaro, C. (C.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Biasuzzi, B. (B.), Biland, A. (A.), Blanch, O. (O.), Bonnefoy, S. (S.), Bonnoli, G. (G.), Borracci, F. (F.), Bretz, T. (T.), Carosi, R. (R.), Carosi, A. (A.), Chatterjee, A. (A.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), Cumani, P. (P.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), de Ona Wilhelmi, E. (E.), Di Pierro, F. (F.), Doert, M. (M.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Glawion, D. E. (D. Eisenacher), Elsaesser, D. (D.), Engelkemeier, M. (M.), Ramazani, V. F. (V. Fallah), Fernandez-Barral, A. (A.), Fidalgo, D. (D.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Gora, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Hayashida, M. (M.), Herrera, J. (J.), Hose, J. (J.), Hrupec, D. (D.), Hughes, G. (G.), Idec, W. (W.), Ishio, K. (K.), Kodani, K. (K.), Konno, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lelas, D. (D.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Majumdar, P. (P.), Makariev, M. (M.), Mallot, K. (K.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Menzel, U. (U.), Mirzoyan, R. (R.), Moralejo, A. (A.), Moretti, E. (E.), Nakajima, D. (D.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Rosillo, M. N. (M. Nievas), Nilsson, K. (K.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nothe, M. (M.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Paredes-Fortuny, X. (X.), Pedaletti, G. (G.), Peresano, M. (M.), Perri, L. (L.), Persic, M. (M.), Poutanen, J. (J.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Garcia, J. R. (J. R.), Reichardt, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Saito, T. (T.), Satalecka, K. (K.), Schroeder, S. (S.), Schweizer, T. (T.), Shore, S. N. (S. N.), Sillanpaa, A. (A.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Takalo, L. (L.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Tescaro, D. (D.), Teshima, M. (M.), Torres, D. F. (D. F.), Torres-Alba, N. (N.), Toyama, T. (T.), Treves, A. (A.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Wu, M. H. (M. H.), Krauss, F. (F.), Schulz, R. (R.), Kadler, M. (M.), Wilms, J. (J.), Ros, E. (E.), Bach, U. (U.), Beuchert, T. (T.), Langejahn, M. (M.), Wendel, C. (C.), Gehrels, N. (N.), Baumgartner, W. H. (W. H.), Markwardt, C. B. (C. B.), Muller, C. (C.), Grinberg, V. (V.), Hovatta, T. (T.), Magill, J. (J.), Ahnen, M. L. (M. L.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Arcaro, C. (C.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Biasuzzi, B. (B.), Biland, A. (A.), Blanch, O. (O.), Bonnefoy, S. (S.), Bonnoli, G. (G.), Borracci, F. (F.), Bretz, T. (T.), Carosi, R. (R.), Carosi, A. (A.), Chatterjee, A. (A.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), Cumani, P. (P.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), de Ona Wilhelmi, E. (E.), Di Pierro, F. (F.), Doert, M. (M.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Glawion, D. E. (D. Eisenacher), Elsaesser, D. (D.), Engelkemeier, M. (M.), Ramazani, V. F. (V. Fallah), Fernandez-Barral, A. (A.), Fidalgo, D. (D.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Gora, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Hayashida, M. (M.), Herrera, J. (J.), Hose, J. (J.), Hrupec, D. (D.), Hughes, G. (G.), Idec, W. (W.), Ishio, K. (K.), Kodani, K. (K.), Konno, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lelas, D. (D.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Majumdar, P. (P.), Makariev, M. (M.), Mallot, K. (K.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Menzel, U. (U.), Mirzoyan, R. (R.), Moralejo, A. (A.), Moretti, E. (E.), Nakajima, D. (D.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Rosillo, M. N. (M. Nievas), Nilsson, K. (K.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nothe, M. (M.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Paredes-Fortuny, X. (X.), Pedaletti, G. (G.), Peresano, M. (M.), Perri, L. (L.), Persic, M. (M.), Poutanen, J. (J.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Garcia, J. R. (J. R.), Reichardt, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Saito, T. (T.), Satalecka, K. (K.), Schroeder, S. (S.), Schweizer, T. (T.), Shore, S. N. (S. N.), Sillanpaa, A. (A.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Takalo, L. (L.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Tescaro, D. (D.), Teshima, M. (M.), Torres, D. F. (D. F.), Torres-Alba, N. (N.), Toyama, T. (T.), Treves, A. (A.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Wu, M. H. (M. H.), Krauss, F. (F.), Schulz, R. (R.), Kadler, M. (M.), Wilms, J. (J.), Ros, E. (E.), Bach, U. (U.), Beuchert, T. (T.), Langejahn, M. (M.), Wendel, C. (C.), Gehrels, N. (N.), Baumgartner, W. H. (W. H.), Markwardt, C. B. (C. B.), Muller, C. (C.), Grinberg, V. (V.), Hovatta, T. (T.), and Magill, J. (J.)

Abstract

Context: The extragalactic very-high-energy gamma-ray sky is rich in blazars. These are jetted active galactic nuclei that are viewed at a small angle to the line-of-sight. Only a handful of objects viewed at a larger angle are so far known to emit above 100 GeV. Multi-wavelength studies of such objects up to the highest energies provide new insights into the particle and radiation processes of active galactic nuclei. Aims: We aim to report the results from the first multi-wavelength campaign observing the TeV detected nucleus of the active galaxy IC 310, whose jet is observed at a moderate viewing angle of 10°−20°. Methods: The multi-instrument campaign was conducted between 2012 November and 2013 January, and involved observations with MAGIC, Fermi, INTEGRAL, Swift, OVRO, MOJAVE and EVN. These observations were complemented with archival data from the AllWISE and 2MASS catalogs. A one-zone synchrotron self-Compton model was applied to describe the broadband spectral energy distribution. Results: IC 310 showed an extraordinary TeV flare at the beginning of the campaign, followed by a low, but still detectable TeV flux. Compared to previous measurements in this energy range, the spectral shape was found to be steeper during the low emission state. Simultaneous observations in the soft X-ray band showed an enhanced energy flux state and a harder-when-brighter spectral shape behavior. No strong correlated flux variability was found in other frequency regimes. The broadband spectral energy distribution obtained from these observations supports the hypothesis of a double-hump structure. Conclusions: The harder-when-brighter trend in the X-ray and VHE emission, observed for the first time during this campaign, is consistent with the behavior expected from a synchrotron self-Compton scenario. The contemporaneous broadband spectral energy distribution is well described with a one-zone synchrotron self-Compton model using parameters that are comparable to those fou

Published
2017

5. No Fukushima Dai-ichi derived plutonium signal in marine sediments collected 1.5-57km from the reactors.

Author

Wendel CCS, Lind OC, Fifield LK, Tims SG, Salbu B, and Oughton DH

Abstract

Based on AMS analysis, it is shown that no Pu signals from the Fukushima accident could be discerned in marine sediments collected 1.5-57km away from the Fukushima Da-ichi power plant (FDNPP), which were clearly influenced by accident-derived radiocesium. The 240 Pu/ 239 Pu atom ratios (0.21-0.28) were significantly higher than terrestrial global fallout (0.182 ± 0.005), but still in agreement with pre-FDNPP accident baseline data for Pu in near coastal seawaters influenced by global fallout and long-range transport of Pu from the Pacific Proving Grounds., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Published
2017
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6. Chronology of Pu isotopes and 236U in an Arctic ice core.

Author

Wendel CC, Oughton DH, Lind OC, Skipperud L, Fifield LK, Isaksson E, Tims SG, and Salbu B

Subjects
Arctic Regions, Autoradiography, History, 20th Century, Mass Spectrometry, Radiation Monitoring history, USSR, Atmosphere chemistry, Ice Cover chemistry, Plutonium analysis, Radiation Monitoring methods, Radioactive Fallout analysis, Uranium analysis
Abstract

In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of (236)U, (239)Pu, and (240)Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and (236)U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of (239+240)Pu ranged from 0.008 to 0.254 mBq cm(-2) and (236)U from 0.0039 to 0.053 μBq cm(-2). Concentrations varied in concordance with (137)Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and (236)U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The (240)Pu/(239)Pu ratio ranged from 0.15 to 0.19, and (236)U/(239)Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to (236)U concentrations and (236)U/(239)Pu atom ratios in the Arctic and in ice cores., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Published
2013
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