Title: | First Detection of X-Ray Polarization from the Accreting Neutron Star 4U 1820−303 |
Authors: | DI MARCO, Alessandro LA MONACA, Fabio Poutanen, Juri Russell, Thomas D. ANITRA, Alessio FARINELLI, Ruben MASTROSERIO, Guglielmo MULERI, FABIO XIE, FEI BACHETTI, Matteo BURDERI, LUCIANO RATHEESH, AJAY Roberts, Oliver J. Romani, Roger W. Sgrò, Carmelo Slane, Patrick Spandre, Gloria Swartz, Douglas A. Tamagawa, Toru TAVECCHIO, Fabrizio Taverna, Roberto CAROTENUTO, Francesco Tawara, Yuzuru Tennant, Allyn F. Thomas, Nicholas E. TOMBESI, Francesco TROIS, ALESSIO Tsygankov, Sergey S. Turolla, Roberto Vink, Jacco Wu, Kinwah DEL SANTO, MELANIA Di Salvo, Tiziana Dovčiak, Michal Gnarini, Andrea Iaria, Rosario Kajava, Jari J. E. Liu, Kuan MIDDEI, Riccardo O’Dell, Stephen L. PILIA, Maura RANKIN, John SANNA, ANDREA Eijnden, Jakob van den Weisskopf, Martin C. Bobrikova, Anna CAPITANIO, FIAMMA COSTA, ENRICO Kaaret, Philip MARINO, ALESSIO SOFFITTA, PAOLO Ursini, Francesco AMBROSINO, Filippo COCCHI, Massimo FABIANI, Sergio Marshall, Herman L. Matt, Giorgio MOTTA, Sara Elisa PAPITTO, ALESSANDRO STELLA, Luigi TARANA, Antonella Zane, Silvia Agudo, Iván ANTONELLI, Lucio Angelo Baldini, Luca Baumgartner, Wayne H. Bellazzini, Ronaldo Bianchi, Stefano Bongiorno, Stephen D. Bonino, Raffaella Brez, Alessandro BUCCIANTINI, Niccolo' Castellano, Simone Cavazzuti, Elisabetta Chen, Chien-Ting Ciprini, Stefano DE ROSA, Alessandra DEL MONTE, Ettore Di Gesu, Laura Di Lalla, Niccolò Donnarumma, Immacolata Doroshenko, Victor Ehlert, Steven R. Enoto, Teruaki EVANGELISTA, YURI FERRAZZOLI, RICCARDO Garcia, Javier A. Gunji, Shuichi Hayashida, Kiyoshi Heyl, Jeremy Iwakiri, Wataru Jorstad, Svetlana G. Karas, Vladimir Kislat, Fabian Kitaguchi, Takao Kolodziejczak, Jeffery J. Krawczynski, Henric Latronico, Luca Liodakis, Ioannis Maldera, Simone Manfreda, Alberto Marin, Frédéric Marinucci, Andrea Marscher, Alan P. MASSARO, Francesco Mitsuishi, Ikuyuki Mizuno, Tsunefumi Negro, Michela Ng, Chi-Yung Omodei, Nicola Oppedisano, Chiara Pavlov, George G. Peirson, Abel L. PERRI, Matteo Pesce-Rollins, Melissa Petrucci, Pierre-Olivier POSSENTI, ANDREA Puccetti, Simonetta Ramsey, Brian D. |
Issue Date: | 2023 |
Journal: | THE ASTROPHYSICAL JOURNAL LETTERS |
Number: | 953 |
Issue: | 2 |
First Page: | L22 |
Abstract: | This paper reports the first detection of polarization in the X-rays for atoll-source 4U 1820-303, obtained with the Imaging X-ray Polarimetry Explorer (IXPE) at 99.999% confidence level (CL). Simultaneous polarimetric measurements were also performed in the radio with the Australia Telescope Compact Array. The IXPE observations of 4U 1820-303 were coordinated with Swift X-ray Telescope, Neutron Star Interior Composition Explorer, and Nuclear Spectroscopic Telescope Array aiming to obtain an accurate X-ray spectral model covering a broad energy interval. The source shows a significant polarization above 4 keV, with a polarization degree of 2.0% ± 0.5% and a polarization angle of -55° ± 7° in the 4-7 keV energy range, and a polarization degree of 10% ± 2% and a polarization angle of -67° ± 7° in the 7-8 keV energy bin. This polarization also shows a clear energy trend with polarization degree increasing with energy and a hint for a position-angle change of ≃90° at 96% CL around 4 keV. The spectro-polarimetric fit indicates that the accretion disk is polarized orthogonally to the hard spectral component, which is presumably produced in the boundary/spreading layer. We do not detect linear polarization from the radio counterpart, with a 3σ upper limit of 50% at 7.25 GHz. |
URI: | http://hdl.handle.net/20.500.12386/34532 |
URL: | https://iopscience.iop.org/article/10.3847/2041-8213/acec6e https://api.elsevier.com/content/abstract/scopus_id/85169325138 |
ISSN: | 2041-8205 |
DOI: | 10.3847/2041-8213/acec6e |
Bibcode ADS: | 2023ApJ...953L..22D |
Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista
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