Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE
Creators: name: Veledina, Alexandra
name: Muleri, Fabio
name: Poutanen, Juri
name: Podgorný, Jakub
name: Dovčiak, Michal
name: Capitanio, Fiamma
name: Churazov, Eugene
name: De Rosa, Alessandra
name: Di Marco, Alessandro
name: Forsblom, Sofia
name: Kaaret, Philip
name: Krawczynski, Henric
name: La Monaca, Fabio
name: Loktev, Vladislav
name: Lutovinov, Alexander A.
name: Molkov, Sergey V.
name: Mushtukov, Alexander A.
name: Ratheesh, Ajay
name: Cavero, Nicole Rodriguez
name: Steiner, James F.
name: Sunyaev, Rashid A.
name: Tsygankov, Sergey S.
name: Zdziarski, Andrzej A.
name: Bianchi, Stefano
name: Bright, Joe S.
name: Bursov, Nikolaj
name: Costa, Enrico
name: Egron, Elise
name: Garcia, Javier A.
name: Green, David A.
name: Gurwell, Mark
name: Ingram, Adam
name: Kajava, Jari J. E.
name: Kale, Ruta
name: Kraus, Alex
name: Malyshev, Denys
name: Marin, Frédéric
name: Matt, Giorgio
name: McCollough, Michael
name: Mereminskiy, Ilia A.
name: Nizhelsky, Nikolaj
name: Piano, Giovanni
name: Pilia, Maura
name: Pittori, Carlotta
name: Rao, Ramprasad
name: Righini, Simona
name: Soffitta, Paolo
name: Shevchenko, Anton
name: Svoboda, Jiri
name: Tombesi, Francesco
name: Trushkin, Sergei
name: Tsybulev, Peter
name: Ursini, Francesco
name: Weisskopf, Martin C.
name: Wu, Kinwah
name: Agudo, Iván
name: Antonelli, Lucio A.
name: Bachetti, Matteo
name: Baldini, Luca
name: Baumgartner, Wayne H.
name: Bellazzini, Ronaldo
name: Bongiorno, Stephen D.
name: Bonino, Raffaella
name: Brez, Alessandro
name: Bucciantini, Niccolò
name: Castellano, Simone
name: Cavazzuti, Elisabetta
name: Chen, Chien-Ting
name: Ciprini, Stefano
name: Del Monte, Ettore
name: Di Gesu, Laura
name: Di Lalla, Niccolò
name: Donnarumma, Immacolata
name: Doroshenko, Victor
name: Ehlert, Steven R.
name: Enoto, Teruaki
name: Evangelista, Yuri
name: Fabiani, Sergio
name: Ferrazzoli, Riccardo
name: Gunji, Shuichi
name: Hayashida, Kiyoshi
name: Heyl, Jeremy
name: Iwakiri, Wataru
name: Jorstad, Svetlana G.
name: Karas, Vladimir
name: Kislat, Fabian
name: Kitaguchi, Takao
name: Kolodziejczak, Jeffery J.
name: Latronico, Luca
name: Liodakis, Ioannis
name: Maldera, Simone
name: Manfreda, Alberto
name: Marinucci, Andrea
name: Marscher, Alan P.
name: Marshall, Herman L.
name: Massaro, Francesco
name: Mitsuishi, Ikuyuki
name: Mizuno, Tsunefumi
name: Negro, Michela
name: Ng, Chi-Yung
name: O'Dell, Stephen L.
name: Omodei, Nicola
name: Oppedisano, Chiara
name: Papitto, Alessandro
name: Pavlov, George G.
name: Peirson, Abel L.
name: Perri, Matteo
name: Pesce-Rollins, Melissa
name: Petrucci, Pierre-Olivier
name: Possenti, Andrea
name: Puccetti, Simonetta
name: Ramsey, Brian D.
name: Rankin, John
name: Roberts, Oliver
name: Romani, Roger W.
name: Sgrò, Carmelo
name: Slane, Patrick
name: Spandre, Gloria
name: Swartz, Doug
name: Tamagawa, Toru
name: Tavecchio, Fabrizio
name: Taverna, Roberto
name: Tawara, Yuzuru
name: Tennant, Allyn F.
name: Thomas, Nicholas E.
name: Trois, Alessio
name: Turolla, Roberto
name: Vink, Jacco
name: Xie, Fei
name: Zane, Silvia
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The accretion of matter by compact objects can be inhibited by radiation pressure if the luminosity exceeds the critical value, known as the Eddington limit. Discovery of ultraluminous X-ray sources has shown that accretion can proceed even when the apparent luminosity significantly exceeds this limit. High apparent luminosity might be produced thanks to geometric beaming of the radiation by an outflow. The outflow half-opening angle, which determines the amplification due to beaming, has never been robustly constrained. Using the Imaging X-ray Polarimetry Explorer, we made the measurement of X-ray polarization in the Galactic X-ray binary Cyg X-3. We find high, over 20%, nearly energy-independent linear polarization, orthogonal to the direction of the radio ejections. These properties unambiguously indicate the presence of a collimating outflow in the X-ray binary Cyg~X-3 and constrain its half-opening angle, &lt;15 degrees. Thus, the source can be used as a laboratory for studying the super-critical accretion regime. This finding underscores the importance of X-ray polarimetry in advancing our understanding of accreting sources.
description: 52 pages, 14 figures, 3 tables. Author version of the article published in Nature Astronomy