학술논문
X-Ray Polarimetry of the Dipping Accreting Neutron Star 4U 1624–49
Document Type
article
Author
M. Lynne Saade; Philip Kaaret; Andrea Gnarini; Juri Poutanen; Francesco Ursini; Stefano Bianchi; Anna Bobrikova; Fabio La Monaca; Alessandro Di Marco; Fiamma Capitanio; Alexandra Veledina; Iván Agudo; Lucio A. Antonelli; Matteo Bachetti; Luca Baldini; Wayne H. Baumgartner; Ronaldo Bellazzini; Stephen D. Bongiorno; Raffaella Bonino; Alessandro Brez; Niccolò Bucciantini; Simone Castellano; Elisabetta Cavazzuti; Chien-Ting Chen; Stefano Ciprini; Enrico Costa; Alessandra De Rosa; Ettore Del Monte; Laura Di Gesu; Niccolò Di Lalla; Immacolata Donnarumma; Victor Doroshenko; Michal Dovčiak; Steven R. Ehlert; Teruaki Enoto; Yuri Evangelista; Sergio Fabiani; Riccardo Ferrazzoli; Javier A. García; Shuichi Gunji; Kiyoshi Hayashida; Jeremy Heyl; Wataru Iwakiri; Svetlana G. Jorstad; Vladimir Karas; Fabian Kislat; Takao Kitaguchi; Jeffery J. Kolodziejczak; Henric Krawczynski; Luca Latronico; Ioannis Liodakis; Simone Maldera; Alberto Manfreda; Frédéric Marin; Andrea Marinucci; Alan P. Marscher; Herman L. Marshall; Francesco Massaro; Giorgio Matt; Ikuyuki Mitsuishi; Tsunefumi Mizuno; Fabio Muleri; Michela Negro; Chi-Yung Ng; Stephen L. O’Dell; Nicola Omodei; Chiara Oppedisano; Alessandro Papitto; George G. Pavlov; Abel L. Peirson; Matteo Perri; Melissa Pesce-Rollins; Pierre-Olivier Petrucci; Maura Pilia; Andrea Possenti; Simonetta Puccetti; Brian D. Ramsey; John Rankin; Ajay Ratheesh; Oliver J. Roberts; Roger W. Romani; Carmelo Sgrò; Patrick Slane; Paolo Soffitta; Gloria Spandre; Douglas A. Swartz; Toru Tamagawa; Fabrizio Tavecchio; Roberto Taverna; Yuzuru Tawara; Allyn F. Tennant; Nicholas E. Thomas; Francesco Tombesi; Alessio Trois; Sergey S. Tsygankov; Roberto Turolla; Jacco Vink; Martin C. Weisskopf; Kinwah Wu; Fei Xie; Silvia Zane
Source
The Astrophysical Journal, Vol 963, Iss 2, p 133 (2024)
Subject
Language
English
ISSN
1538-4357
Abstract
We present the first X-ray polarimetric study of the dipping accreting neutron star 4U 1624−49 with the Imaging X-ray Polarimetry Explorer. We report a detection of polarization in the nondip time intervals with a confidence level of 99.99%. We find an average polarization degree (PD) of 3.1% ± 0.7% and a polarization angle of 81° ± 6° east of north in the 2–8 keV band. We report an upper limit on the PD of 22% during the X-ray dips with 95% confidence. The PD increases with energy, reaching from 3.0% ± 0.9% in the 4–6 keV band to 6% ± 2% in the 6–8 keV band. This indicates the polarization likely arises from Comptonization. The high PD observed is unlikely to be produced by Comptonization in the boundary layer or spreading layer alone. It can be produced by the addition of an extended geometrically thin slab corona covering part of the accretion disk, as assumed in previous models of dippers, and/or a reflection component from the accretion disk.