Tracking the X-Ray Polarization of the Black Hole Transient Swift J1727.8-1613 during a State Transition
Articolo
Data di Pubblicazione:
2024
Abstract:
We report on an observational campaign on the bright black hole (BH) X-ray binary Swift J1727.8-1613 centered around five observations by the Imaging X-ray Polarimetry Explorer. These observations track for the first time the evolution of the X-ray polarization of a BH X-ray binary across a hard to soft state transition. The 2-8 keV polarization degree decreased from ∼4% to ∼3% across the five observations, but the polarization angle remained oriented in the north-south direction throughout. Based on observations with the Australia Telescope Compact Array, we find that the intrinsic 7.25 GHz radio polarization aligns with the X-ray polarization. Assuming the radio polarization aligns with the jet direction (which can be tested in the future with higher-spatial-resolution images of the jet), our results imply that the X-ray corona is extended in the disk plane, rather than along the jet axis, for the entire hard intermediate state. This in turn implies that the long (≳10 ms) soft lags that we measure with the Neutron star Interior Composition ExploreR are dominated by processes other than pure light-crossing delays. Moreover, we find that the evolution of the soft lag amplitude with spectral state does not follow the trend seen for other sources, implying that Swift J1727.8-1613 is a member of a hitherto undersampled subpopulation.
Tipologia CRIS:
03A-Articolo su Rivista
Elenco autori:
Ingram A.; Bollemeijer N.; Veledina A.; Dovciak M.; Poutanen J.; Egron E.; Russell T.D.; Trushkin S.A.; Negro M.; Ratheesh A.; Capitanio F.; Connors R.; Neilsen J.; Kraus A.; Iacolina M.N.; Pellizzoni A.; Pilia M.; Carotenuto F.; Matt G.; Mastroserio G.; Kaaret P.; Bianchi S.; Garcia J.A.; Bachetti M.; Wu K.; Costa E.; Ewing M.; Kravtsov V.; Krawczynski H.; Loktev V.; Marinucci A.; Marra L.; Mikusincova R.; Nathan E.; Parra M.; Petrucci P.-O.; Righini S.; Soffitta P.; Steiner J.F.; Svoboda J.; Tombesi F.; Tugliani S.; Ursini F.; Yang Y.-J.; Zane S.; Zhang W.; Agudo I.; Antonelli L.A.; Baldini L.; Baumgartner W.H.; Bellazzini R.; Bongiorno S.D.; Bonino R.; Brez A.; Bucciantini N.; Castellano S.; Cavazzuti E.; Chen C.-T.; Ciprini S.; De Rosa A.; Del Monte E.; Di Gesu L.; Di Lalla N.; Di Marco A.; Donnarumma I.; Doroshenko V.; Ehlert S.R.; Enoto T.; Evangelista Y.; Fabiani S.; Ferrazzoli R.; Gunji S.; Hayashida K.; Heyl J.; Iwakiri W.; Jorstad S.G.; Karas V.; Kislat F.; Kitaguchi T.; Kolodziejczak J.J.; La Monaca F.; Latronico L.; Liodakis I.; Maldera S.; Manfreda A.; Marin F.; Marscher A.P.; Marshall H.L.; Massaro F.; Mitsuishi I.; Mizuno T.; Muleri F.; Ng C.-Y.; O'Dell S.L.; Omodei N.; Oppedisano C.; Papitto A.; Pavlov G.G.; Peirson A.L.; Perri M.; Pesce-Rollins M.; Possenti A.; Puccetti S.; Ramsey B.D.; Rankin J.; Roberts O.J.; Romani R.W.; Sgro C.; Slane P.; Spandre G.; Swartz D.A.; Tamagawa T.; Tavecchio F.; Taverna R.; Tawara Y.; Tennant A.F.; Thomas N.E.; Trois A.; Tsygankov S.S.; Turolla R.; Vink J.; Weisskopf M.C.; Xie F.
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