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An extremely powerful long-lived superluminal ejection from the black hole MAXI J1820+070

Nature Astronomy Nature Research 4:7 (2020) 697-703

Authors:

JS Bright, RP Fender, SE Motta, DRA Williams, J Moldon, RM Plotkin, JCA Miller-Jones, I Heywood, E Tremou, R Beswick, GR Sivakoff, S Corbel, DAH Buckley, J Homan, E Gallo, AJ Tetarenko, TD Russell, DA Green, D Titterington, PA Woudt, RP Armstrong, PJ Groot, A Horesh, AJ van der Horst, EG Kording, VA McBride, A Rowlinson, RAMJ Wijers

Abstract:

Black holes in binary systems execute patterns of outburst activity where two characteristic X-ray states are associated with different behaviours observed at radio wavelengths. The hard state is associated with radio emission indicative of a continuously replenished, collimated, relativistic jet, whereas the soft state is rarely associated with radio emission, and never continuously, implying the absence of a quasi-steady jet. Here we report radio observations of the black hole transient MAXI J1820+070 during its 2018 outburst. As the black hole transitioned from the hard to soft state, we observed an isolated radio flare, which, using high-angular-resolution radio observations, we connect with the launch of bipolar relativistic ejecta. This flare occurs as the radio emission of the core jet is suppressed by a factor of over 800. We monitor the evolution of the ejecta over 200 days and to a maximum separation of 10″, during which period it remains detectable due to in situ particle acceleration. Using simultaneous radio observations sensitive to different angular scales, we calculate an accurate estimate of energy content of the approaching ejection. This energy estimate is far larger than that derived from the state transition radio flare, suggesting a systematic underestimate of jet energetics.
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An extremely powerful long-lived superluminal ejection from the black hole MAXI J1820+070

(2020)

Authors:

JS Bright, RP Fender, SE Motta, DRA Williams, J Moldon, RM Plotkin, JCA Miller-Jones, I Heywood, E Tremou, R Beswick, GR Sivakoff, S Corbel, DAH Buckley, J Homan, E Gallo, AJ Tetarenko, TD Russell, DA Green, D Titterington, PA Woudt, RP Armstrong, PJ Groot, A Horesh, AJ van der Horst, EG Körding, VA McBride, A Rowlinson, RAMJ Wijers
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A spectroscopic, photometric, polarimetric, and radio study of the eclipsing polar UZ Fornacis: the first simultaneous SALT and MeerKAT observations

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 492:3 (2020) 4298-4312

Authors:

ZN Khangale, SB Potter, PA Woudt, DAH Buckley, AN Semena, EJ Kotze, DN Groenewald, DM Hewitt, ML Pretorius, RP Fender, P Groot, S Bloemen, M Klein-Wolt, E Körding, R Le Poole, VA McBride, L Townsend, K Paterson, DLA Pieterse, P Vreeswijk
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Propagation of cosmic rays and their secondaries in the intracluster medium

Proceedings of the International Astronomical Union 15 (2020) 178-179

Authors:

S Hussain, R Alves Batista, EM de Gouveia Dal Pino, K Dolag

Abstract:

We present results of the propagation of high-energy cosmic rays (CRs) and their secondaries in the intracluster medium (ICM). To this end, we employ three-dimensional cosmological magnetohydrodynamical simulations of the turbulent intergalactic medium to explore the propagation of CRs with energies between 1014 and 1019 eV. We study the interaction of test particles with this environment considering all relevant electromagnetic, photohadronic, photonuclear, and hadronuclear processes. Finally, we discuss the consequences of the confinement of high-energy CRs in clusters for the production of gamma rays and neutrinos.
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Detection of very-high-energy γ-ray emission from the colliding wind binary η Car with H.E.S.S.

Astronomy & Astrophysics EDP Sciences 635 (2020) a167

Authors:

H Abdalla, R Adam, F Aharonian, F Ait Benkhali, EO Angüner, M Arakawa, C Arcaro, C Armand, T Armstrong, H Ashkar, M Backes, V Barbosa Martins, M Barnard, Y Becherini, D Berge, K Bernlöhr, R Blackwell, M Böttcher, C Boisson, J Bolmont, S Bonnefoy, J Bregeon, M Breuhaus, F Brun, P Brun, M Bryan, M Büchele, T Bulik, T Bylund, S Caroff, A Carosi, S Casanova, M Cerruti, T Chand, S Chandra, A Chen, S Colafrancesco, G Cotter, M Curyło, ID Davids, J Davies, C Deil, J Devin, P deWilt, L Dirson, A Djannati-Ataï, A Dmytriiev, A Donath, V Doroshenko, J Dyks, K Egberts, F Eichhorn, G Emery, J-P Ernenwein, S Eschbach, K Feijen, S Fegan, A Fiasson, G Fontaine, S Funk, M Füßling, S Gabici, YA Gallant, F Gaté, G Giavitto, L Giunti, D Glawion, JF Glicenstein, D Gottschall, M-H Grondin, J Hahn, M Haupt, G Heinzelmann, G Henri, G Hermann, JA Hinton, W Hofmann, C Hoischen, TL Holch, M Holler, M Hörbe, D Horns, D Huber, H Iwasaki, M Jamrozy, D Jankowsky, F Jankowsky, A Jardin-Blicq, V Joshi, I Jung-Richardt, MA Kastendieck, K Katarzyński, M Katsuragawa, U Katz, D Khangulyan, B Khélifi, J King, S Klepser, W Kluźniak, Nu Komin, K Kosack, D Kostunin, M Kreter, G Lamanna, A Lemière, M Lemoine-Goumard, J-P Lenain, E Leser, C Levy, T Lohse, I Lypova, J Mackey, J Majumdar, D Malyshev, D Malyshev, V Marandon, P Marchegiani, A Marcowith, A Mares, G Martí-Devesa, R Marx, G Maurin, PJ Meintjes, R Moderski, M Mohamed, L Mohrmann, C Moore, P Morris, E Moulin, J Muller, T Murach, S Nakashima, K Nakashima, M de Naurois, H Ndiyavala, F Niederwanger, J Niemiec, L Oakes, P O’Brien, H Odaka, S Ohm, E de Ona Wilhelmi, M Ostrowski, M Panter, RD Parsons, C Perennes, P-O Petrucci, B Peyaud, Q Piel, S Pita, V Poireau, A Priyana Noel, DA Prokhorov, H Prokoph, G Pühlhofer, M Punch, A Quirrenbach, S Raab, R Rauth, A Reimer, O Reimer, Q Remy, M Renaud, F Rieger, L Rinchiuso, C Romoli, G Rowell, B Rudak, E Ruiz-Velasco, V Sahakian, S Sailer, S Saito, DA Sanchez, A Santangelo, M Sasaki, M Scalici, R Schlickeiser, F Schüssler, A Schulz, HM Schutte, U Schwanke, S Schwemmer, M Seglar-Arroyo, M Senniappan, AS Seyffert, N Shafi, K Shiningayamwe, R Simoni, A Sinha, H Sol, A Specovius, S Spencer, M Spir-Jacob, Ł Stawarz, R Steenkamp, C Stegmann, C Steppa, T Takahashi, T Tavernier, AM Taylor, R Terrier, D Tiziani, M Tluczykont, L Tomankova, C Trichard, M Tsirou, N Tsuji, R Tuffs, Y Uchiyama, DJ van der Walt, C van Eldik, C van Rensburg, B van Soelen, G Vasileiadis, J Veh, C Venter, P Vincent, J Vink, HJ Völk, T Vuillaume, Z Wadiasingh, SJ Wagner, J Watson, F Werner, R White, A Wierzcholska, R Yang, H Yoneda, M Zacharias, R Zanin, AA Zdziarski, A Zech, J Zorn, N Żywucka
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