Title: | Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5−1 |
Authors: | FABIANI, Sergio CAPITANIO, FIAMMA Iaria, Rosario Poutanen, Juri Gnarini, Andrea Ursini, Francesco FARINELLI, Ruben Bobrikova, Anna Steiner, James F. Svoboda, Jiri ANITRA, Alessio Romani, Roger W. Sgrò, Carmelo Slane, Patrick SOFFITTA, PAOLO Spandre, Gloria Swartz, Douglas A. Tamagawa, Toru TAVECCHIO, Fabrizio Taverna, Roberto Tawara, Yuzuru Baglio, Maria C. Tennant, Allyn F. Thomas, Nicholas E. TOMBESI, Francesco TROIS, ALESSIO Tsygankov, Sergey S. Turolla, Roberto Vink, Jacco Wu, Kinwah Zane, Silvia CAROTENUTO, Francesco DEL SANTO, MELANIA Ferrigno, Carlo Lewis, Fraser Russell, David M. Russell, Thomas D. van den Eijnden, Jakob COCCHI, Massimo DI MARCO, Alessandro LA MONACA, Fabio Liu, Kuan RANKIN, John Weisskopf, Martin C. XIE, FEI Bianchi, Stefano BURDERI, Luciano Di Salvo, Tiziana EGRON, Elise Marie Jeanne ILLIANO, Giulia Kaaret, Philip Matt, Giorgio MIKUSINCOVA, Romana MULERI, FABIO PAPITTO, ALESSANDRO Agudo, Iván ANTONELLI, Lucio Angelo BACHETTI, Matteo Baldini, Luca Baumgartner, Wayne H. Bellazzini, Ronaldo Bongiorno, Stephen D. Bonino, Raffaella Brez, Alessandro BUCCIANTINI, Niccolo' Castellano, Simone Cavazzuti, Elisabetta Chen, Chien-Ting Ciprini, Stefano COSTA, ENRICO DE ROSA, Alessandra DEL MONTE, Ettore Di Gesu, Laura Di Lalla, Niccolò Donnarumma, Immacolata Doroshenko, Victor Dovčiak, Michal 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. Marshall, Herman L. MASSARO, Francesco Mitsuishi, Ikuyuki Mizuno, Tsunefumi Negro, Michela Ng, Chi-Yung O'Dell, Stephen L. Omodei, Nicola Oppedisano, Chiara Pavlov, George G. Peirson, Abel L. PERRI, Matteo Pesce-Rollins, Melissa Petrucci, Pierre-Olivier PILIA, Maura POSSENTI, ANDREA Puccetti, Simonetta Ramsey, Brian D. RATHEESH, AJAY Roberts, Oliver J. |
Issue Date: | 2024 |
Journal: | ASTRONOMY & ASTROPHYSICS |
Number: | 684 |
First Page: | A137 |
Abstract: | We report on the coordinated observations of the neutron star low-mass X-ray binary (NS-LMXB) GX 5−1 in X-rays (IXPE, NICER, NuSTAR, and INTEGRAL), optical (REM and LCO), near-infrared (REM), mid-infrared (VLT VISIR), and radio (ATCA). This Z-source was observed by IXPE twice in March-April 2023 (Obs. 1 and 2). In the radio band the source was detected, but only upper limits to the linear polarization were obtained at a 3σ level of 6.1% at 5.5 GHz and 5.9% at 9 GHz in Obs. 1 and 12.5% at 5.5 GHz and 20% at 9 GHz in Obs. 2. The mid-IR, near-IR, and optical observations suggest the presence of a compact jet that peaks in the mid- or far-IR. The X-ray polarization degree was found to be 3.7%±0.4% (at 90% confidence level) during Obs. 1 when the source was in the horizontal branch of the Z-track and 1.8%±0.4% during Obs. 2 when the source was in the normal-flaring branch. These results confirm the variation in polarization degree as a function of the position of the source in the color-color diagram, as for previously observed Z-track sources (Cyg X-2 and XTE 1701−462). Evidence of a variation in the polarization angle of ∼20° with energy is found in both observations, likely related to the different, nonorthogonal polarization angles of the disk and Comptonization components, which peak at different energies. |
URI: | http://hdl.handle.net/20.500.12386/35508 |
URL: | https://www.aanda.org/articles/aa/full_html/2024/04/aa47374-23/aa47374-23.html https://api.elsevier.com/content/abstract/scopus_id/85191066187 |
ISSN: | 0004-6361 |
DOI: | 10.1051/0004-6361/202347374 |
Bibcode ADS: | 2024A&A...684A.137F |
Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista
|