%0 Journal Article
%@ 2397-3366
%A Veledina, Alexandra
%A Muleri, Fabio
%A Poutanen, Juri
%A Podgorný, Jakub
%A Dovčiak, Michal
%A Capitanio, Fiamma
%A Churazov, Eugene
%A De Rosa, Alessandra
%A Di Marco, Alessandro
%A Forsblom, Sofia V
%A Kaaret, Philip
%A Krawczynski, Henric
%A La Monaca, Fabio
%A Loktev, Vladislav
%A Lutovinov, Alexander A
%A Molkov, Sergey V
%A Mushtukov, Alexander A
%A Ratheesh, Ajay
%A Rodriguez Cavero, Nicole
%A Steiner, James F
%A Sunyaev, Rashid A
%A Tsygankov, Sergey S
%A Weisskopf, Martin C
%A Zdziarski, Andrzej A
%A Bianchi, Stefano
%A Bright, Joe S
%A Bursov, Nikolaj
%A Costa, Enrico
%A Egron, Elise
%A Garcia, Javier A
%A Green, David A
%A Gurwell, Mark
%A Ingram, Adam
%A Kajava, Jari JE
%A Kale, Ruta
%A Kraus, Alex
%A Malyshev, Denys
%A Marin, Frédéric
%A Matt, Giorgio
%A McCollough, Michael
%A Mereminskiy, Ilya A
%A Nizhelsky, Nikolaj
%A Piano, Giovanni
%A Pilia, Maura
%A Pittori, Carlotta
%A Rao, Ramprasad
%A Righini, Simona
%A Soffitta, Paolo
%A Shevchenko, Anton
%A Svoboda, Jiri
%A Tombesi, Francesco
%A Trushkin, Sergei A
%A Tsybulev, Peter
%A Ursini, Francesco
%A Wu, Kinwah
%A Agudo, Iván
%A Antonelli, Lucio A
%A Bachetti, Matteo
%A Baldini, Luca
%A Baumgartner, Wayne H
%A Bellazzini, Ronaldo
%A Bongiorno, Stephen D
%A Bonino, Raffaella
%A Brez, Alessandro
%A Bucciantini, Niccolò
%A Castellano, Simone
%A Cavazzuti, Elisabetta
%A Chen, Chien-Ting
%A Ciprini, Stefano
%A Del Monte, Ettore
%A Di Gesu, Laura
%A Di Lalla, Niccolò
%A Donnarumma, Immacolata
%A Doroshenko, Victor
%A Ehlert, Steven R
%A Enoto, Teruaki
%A Evangelista, Yuri
%A Fabiani, Sergio
%A Ferrazzoli, Riccardo
%A Gunji, Shuichi
%A Hayashida, Kiyoshi
%A Heyl, Jeremy
%A Iwakiri, Wataru
%A Jorstad, Svetlana G
%A Karas, Vladimir
%A Kislat, Fabian
%A Kitaguchi, Takao
%A Kolodziejczak, Jeffery J
%A Latronico, Luca
%A Liodakis, Ioannis
%A Maldera, Simone
%A Manfreda, Alberto
%A Marinucci, Andrea
%A Marscher, Alan P
%A Marshall, Herman L
%A Massaro, Francesco
%A Mitsuishi, Ikuyuki
%A Mizuno, Tsunefumi
%A Negro, Michela
%A Ng, Chi-Yung
%A O’Dell, Stephen L
%A Omodei, Nicola
%A Oppedisano, Chiara
%A Papitto, Alessandro
%A Pavlov, George G
%A Peirson, Abel L
%A Perri, Matteo
%A Pesce-Rollins, Melissa
%A Petrucci, Pierre-Olivier
%A Possenti, Andrea
%A Puccetti, Simonetta
%A Ramsey, Brian D
%A Rankin, John
%A Roberts, Oliver
%A Romani, Roger W
%A Sgrò, Carmelo
%A Slane, Patrick
%A Spandre, Gloria
%A Swartz, Doug
%A Tamagawa, Toru
%A Tavecchio, Fabrizio
%A Taverna, Roberto
%A Tawara, Yuzuru
%A Tennant, Allyn F
%A Thomas, Nicholas E
%A Trois, Alessio
%A Turolla, Roberto
%A Vink, Jacco
%A Xie, Fei
%A Zane, Silvia
%D 2024
%F discovery:10196156
%I Springer Science and Business Media LLC
%J Nature Astronomy
%K Compact astrophysical objects, High-energy astrophysics
%P 1031-1046
%T Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE
%U https://discovery.ucl.ac.uk/id/eprint/10196156/
%V 8
%X The accretion of matter by compact objects can be inhibited by radiation pressure if the luminosity exceeds a critical value known as the Eddington limit. The discovery of ultraluminous X-ray sources has shown that accretion can proceed even when the apparent luminosity considerably exceeds this limit. A high apparent luminosity might be produced due to the geometric beaming of 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 measured the X-ray polarization in the Galactic X-ray binary Cygnus X-3 (Cyg X-3). We found high, >20%, nearly energy-independent linear polarization orthogonal to the direction of the radio ejections. These properties unambiguously indicate the presence of a collimating outflow from the X-ray binary Cyg X-3 and constrain its half-opening angle to ≲15°. Thus, the source can be used as a laboratory for studying the supercritical accretion regime. This finding underscores the importance of X-ray polarimetry in advancing our understanding of accreting sources.
%Z This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.