eprintid: 10186104 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/18/61/04 datestamp: 2024-01-25 13:38:12 lastmod: 2024-01-25 13:38:12 status_changed: 2024-01-25 13:38:12 type: article metadata_visibility: show sword_depositor: 699 creators_name: La Monaca, F creators_name: Di Marco, A creators_name: Poutanen, J creators_name: Bachetti, M creators_name: Motta, SE creators_name: Papitto, A creators_name: Pilia, M creators_name: Xie, F creators_name: Bianchi, S creators_name: Bobrikova, A creators_name: Costa, E creators_name: Deng, W creators_name: Ge, MY creators_name: Illiano, G creators_name: Jia, SM creators_name: Krawczynski, H creators_name: Lai, EV creators_name: Liu, K creators_name: Mastroserio, G creators_name: Muleri, F creators_name: Rankin, J creators_name: Soffitta, P creators_name: Veledina, A creators_name: Ambrosino, F creators_name: Del Santo, M creators_name: Chen, W creators_name: Garcia, JA creators_name: Kaaret, P creators_name: Russell, TD creators_name: Wei, WH creators_name: Zhang, SN creators_name: Zuo, C creators_name: Arzoumanian, Z creators_name: Cocchi, M creators_name: Gnarini, A creators_name: Farinelli, R creators_name: Gendreau, K creators_name: Ursini, F creators_name: Weisskopf, MC creators_name: Zane, S creators_name: Agudo, I creators_name: Antonelli, LA creators_name: Baldini, L creators_name: Baumgartner, WH creators_name: Bellazzini, R creators_name: Bongiorno, SD creators_name: Bonino, R creators_name: Brez, A creators_name: Bucciantini, N creators_name: Capitanio, F creators_name: Castellano, S creators_name: Cavazzuti, E creators_name: Chen, CT creators_name: Ciprini, S creators_name: De Rosa, A creators_name: Del Monte, E creators_name: Di Gesu, L creators_name: Di Lalla, N creators_name: Donnarumma, I creators_name: Doroshenko, V creators_name: Dovčiak, M creators_name: Ehlert, SR creators_name: Enoto, T creators_name: Evangelista, Y creators_name: Fabiani, S creators_name: Ferrazzoli, R creators_name: Gunji, S creators_name: Hayashida, K creators_name: Heyl, J creators_name: Iwakiri, W creators_name: Jorstad, SG creators_name: Karas, V creators_name: Kislat, F creators_name: Kitaguchi, T creators_name: Kolodziejczak, JJ creators_name: Latronico, L creators_name: Liodakis, I creators_name: Maldera, S creators_name: Manfreda, A creators_name: Marin, F creators_name: Marinucci, A creators_name: Marscher, AP creators_name: Marshall, HL creators_name: Massaro, F creators_name: Matt, G creators_name: Mitsuishi, I creators_name: Mizuno, T creators_name: Negro, M creators_name: Ng, CY creators_name: O’Dell, SL creators_name: Omodei, N creators_name: Oppedisano, C creators_name: Pavlov, GG creators_name: Peirson, AL creators_name: Perri, M creators_name: Pesce-Rollins, M creators_name: Petrucci, PO creators_name: Possenti, A creators_name: Puccetti, S creators_name: Ramsey, BD title: Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1 ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F63 note: Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence, https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. abstract: The Imaging X-ray Polarimetry Explorer measured with high significance the X-ray polarization of the brightest Z-source, Sco X-1, resulting in the nominal 2–8 keV energy band in a polarization degree of 1.0% ± 0.2% and a polarization angle of 8° ± 6° at a 90% confidence level. This observation was strictly simultaneous with observations performed by NICER, NuSTAR, and Insight-HXMT, which allowed for a precise characterization of its broadband spectrum from soft to hard X-rays. The source has been observed mainly in its soft state, with short periods of flaring. We also observed low-frequency quasiperiodic oscillations. From a spectropolarimetric analysis, we associate a polarization to the accretion disk at <3.2% at 90% confidence level, compatible with expectations for an electron scattering dominated optically thick atmosphere at the Sco X-1 inclination of ∼44°; for the higher-energy Comptonized component, we obtain a polarization of 1.3% ± 0.4%, in agreement with expectations for a slab of Thomson optical depth of ∼7 and an electron temperature of ∼3 keV. A polarization rotation with respect to previous observations by OSO-8 and PolarLight, and also with respect to the radio-jet position angle, is observed. This result may indicate a variation of the polarization with the source state that can be related to relativistic precession or a change in the corona geometry with the accretion flow. date: 2024-01-10 date_type: published official_url: https://doi.org/10.3847/2041-8213/ad132d oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2141354 doi: 10.3847/2041-8213/ad132d lyricists_name: Zane, Silvia lyricists_id: SZANE58 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: The Astrophysical Journal Letters volume: 960 number: 2 article_number: L11 issn: 2041-8205 citation: La Monaca, F; Di Marco, A; Poutanen, J; Bachetti, M; Motta, SE; Papitto, A; Pilia, M; ... Ramsey, BD; + view all <#> La Monaca, F; Di Marco, A; Poutanen, J; Bachetti, M; Motta, SE; Papitto, A; Pilia, M; Xie, F; Bianchi, S; Bobrikova, A; Costa, E; Deng, W; Ge, MY; Illiano, G; Jia, SM; Krawczynski, H; Lai, EV; Liu, K; Mastroserio, G; Muleri, F; Rankin, J; Soffitta, P; Veledina, A; Ambrosino, F; Del Santo, M; Chen, W; Garcia, JA; Kaaret, P; Russell, TD; Wei, WH; Zhang, SN; Zuo, C; Arzoumanian, Z; Cocchi, M; Gnarini, A; Farinelli, R; Gendreau, K; Ursini, F; Weisskopf, MC; Zane, S; Agudo, I; Antonelli, LA; Baldini, L; Baumgartner, WH; Bellazzini, R; Bongiorno, SD; Bonino, R; Brez, A; Bucciantini, N; Capitanio, F; Castellano, S; Cavazzuti, E; Chen, CT; Ciprini, S; De Rosa, A; Del Monte, E; Di Gesu, L; Di Lalla, N; Donnarumma, I; Doroshenko, V; Dovčiak, M; Ehlert, SR; Enoto, T; Evangelista, Y; Fabiani, S; Ferrazzoli, R; Gunji, S; Hayashida, K; Heyl, J; Iwakiri, W; Jorstad, SG; Karas, V; Kislat, F; Kitaguchi, T; Kolodziejczak, JJ; Latronico, L; Liodakis, I; Maldera, S; Manfreda, A; Marin, F; Marinucci, A; Marscher, AP; Marshall, HL; Massaro, F; Matt, G; Mitsuishi, I; Mizuno, T; Negro, M; Ng, CY; O’Dell, SL; Omodei, N; Oppedisano, C; Pavlov, GG; Peirson, AL; Perri, M; Pesce-Rollins, M; Petrucci, PO; Possenti, A; Puccetti, S; Ramsey, BD; - view fewer <#> (2024) Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1. The Astrophysical Journal Letters , 960 (2) , Article L11. 10.3847/2041-8213/ad132d <https://doi.org/10.3847/2041-8213%2Fad132d>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10186104/1/La_Monaca_2024_ApJL_960_L11.pdf