We employ our new model for the polarised emission of accreting X-ray pulsars to describe the emission from the luminous X-ray pulsar Hercules X-1. In contrast with previous works, our model predicts the polarisation parameters independently of spectral formation, and considers the structure and dynamics of the accretion column, as well as the additional effects on propagation due to general relativity and quantum electrodynamics. We find that our model can describe the observed pulse fraction and the pulse shape of the main peak, as well as the modulation of the cyclotron line with phase. We pick two geometries, assuming a single accretion column or two columns at the magnetic poles, that can describe current observations of pulse shape and cyclotron modulation with phase. Both models predict a high polarisation fraction, between 60 and 80\% in the $1-10$ keV range, that is phase- and energy-dependent, and that peaks at the same phase as the intensity. The phase and energy dependence of the polarisation fraction and of the polarisation angle can help discern between the different geometries.
Fingerprints of thermal Comptonization in accreting neutron stars. Plasma-vacuum interplay in cyclotron lines and polarisation
Dr. Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics, Friedrich-Alexander Universität Erlangen-Nürnberg(弗里德里希-亚历山大埃尔朗根-纽伦堡大学卡尔·雷梅斯天文台和埃尔朗根天体粒子物理中心);INAF - IASF Palermo(意大利国家天体物理研究所巴勒莫分院);Dipartimento di Fisica e Chimica Emilio Segrè, Università degli Studi di Palermo(巴勒莫大学埃米利奥·塞格雷物理与化学系);Department of Astronomy, University of Geneva(日内瓦大学天文学系);INAF, Osservatorio Astronomico di Brera(意大利国家天体物理研究所布里拉天文台);School of Physics and Astronomy, University of Southampton(南安普顿大学物理与天文学学院)
Magnetospheric birefringence breaks the rotating-vector model and depolarises X-ray pulsars
University College London(伦敦大学学院);University of Oxford(牛津大学);University of Turku(图尔库大学);University of Hertfordshire(赫特福德大学);University of Padova(帕多瓦大学)
Polarised X-ray emission from the accreting millisecond pulsar SAX J1808.4-3658 during an X-ray outburst and a type-I X-ray burst
INAF Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);INAF Istituto di Astrofisica e Planetologia Spaziali(意大利国家天体物理研究所天体物理与空间行星学研究所);INAF Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);Institut d’Estudis Espacials de Catalunya (IEEC)(加泰罗尼亚空间研究所)
Dynamic shocks powered by a wide, relativistic, super-Eddington outflow launched by an accreting neutron star in the mid-20th century
University of Oxford(牛津大学);University of Cape Town(开普敦大学);Rhodes University(罗德岛大学);INAF, Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);Max-Planck Institute for Nuclear Physics(马克斯·普朗克核物理研究所);University of Amsterdam(阿姆斯特丹大学)
Probing the $γ$-ray emission region and the connection to jet ejections in NRAO 150 with VLBI
Max-Planck-Institut für Radioastronomie(马克斯·普朗克射电天文研究所);Finnish Centre for Astronomy with ESO, University of Turku(图尔库大学芬兰ESO天文学中心);Aalto University Metsähovi Radio Observatory(阿尔托大学梅特舍霍维射电天文台);Instituto de Astrofísica de Andalucía, IAA-CSIC(安达卢西亚天体物理研究所,西班牙高等科学研究委员会);National Radio Astronomy Observatory(美国国家射电天文台);Institute for Astrophysical Research, Boston University(波士顿大学天体物理研究所);Saint Petersburg State University(圣彼得堡国立大学);Center for Astrophysics | Harvard & Smithsonian(哈佛史密森尼天体物理中心)