A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5−1
Tekijät: Fabiani S, Capitanio F, Iaria R, Poutanen J, Gnarini A, Ursini F, Farinelli R, Bobrikova A, Steiner JF, Svoboda J, Anitra A, Baglio MC, Carotenuto F, Del Santo M, Ferrigno C, Lewis F, Russell DM, Russell TD, Eijnden J, Cocchi M, Di Marco A, La Monaca F, Liu K, Rankin J, Weisskopf MC, Xie F, Bianchi S, Burderi L, Di Salvo T, Egron E, Illiano G, Kaaret P, Matt G, Mikušincová R, Muleri F, Papitto A, Agudo I, Antonelli LA, Bachetti M, Baldini L, Baumgartner WH, Bellazzini R, Bongiorno SD, Bonino R, Brez A, Bucciantini N, Castellano S, Cavazzuti E, Chen C, Ciprini S, Costa E, De Rosa A, Del Monte E, Di Gesu L, Di Lalla N, Donnarumma I, Doroshenko V, Dovčiak M, Ehlert SR, Enoto T, Evangelista Y, Ferrazzoli R, Garcia JA, Gunji S, Hayashida K, Heyl J, Iwakiri W, Jorstad SG, Karas V, Kislat F, Kitaguchi T, Kolodziejczak JJ, Krawczynski H, Latronico L, Liodakis I, Maldera S, Manfreda A, Marin F, Marinucci A, Marscher AP, Marshall HL, Massaro F, Mitsuishi I, Mizuno T, Negro M, Ng C, O’Dell SL, Omodei N, Oppedisano C, Pavlov GG, Peirson AL, Perri M, Pesce-Rollins M, Petrucci P, Pilia M, Possenti A, Puccetti S, Ramsey BD, Ratheesh A, Roberts OJ, Romani RW, Sgrò C, Slane P, Soffitta P, Spandre G, Swartz DA, Tamagawa T, Tavecchio F, Taverna R, Tawara Y, Tennant AF, Thomas NE, Tombesi F, Trois A, Tsygankov SS, Turolla R, Vink J, Wu K, Zane S
Kustantaja: EDP Sciences
Julkaisuvuosi: 2024
Journal: Astronomy and Astrophysics
Tietokannassa oleva lehden nimi: A&A
Artikkelin numero: A137
Vuosikerta: 684
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202347374
Verkko-osoite: https://doi.org/10.1051/0004-6361/202347374
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/393319405
Preprintin osoite: https://arxiv.org/abs/2310.06788
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.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
