Discovery of Strong Energy-Dependent X-ray Polarization in the Intermediate State of GS 1354-64
Massachusetts Institute of Technology（麻省理工学院）；INAF Istituto di Astrofisica e Planetologia Spaziali（意大利国家天体物理研究所）；Center for Astrophysics | Harvard & Smithsonian（哈佛史密松尼天体物理中心）；Scuola Universitaria Superiore IUSS Pavia（帕维亚高等大学）；McGill University（麦吉尔大学）；Villanova University（维拉诺瓦大学）
Swati Ravi, Lorenzo Marra, James F. Steiner, Guglielmo Mastroserio, Mason Ng, Joey Neilsen, Herman L. Marshall, Fiamma Capitanio, Sudeb Ranjan Datta, Elise Egro… 展开作者
Swati Ravi, Lorenzo Marra, James F. Steiner, Guglielmo Mastroserio, Mason Ng, Joey Neilsen, Herman L. Marshall, Fiamma Capitanio, Sudeb Ranjan Datta, Elise Egron, Javier A. Garcia, Adam Ingram, Philip Kaaret, Ole Koenig, Honghui Liu, Romana Mikusincova, Edward J. R. Nathan, P. -O. Petrucci, Jakub Podgorny, Chiara Salvaggio, Jiri Svoboda, Alexandra Veledina, Yuexin Zhang
We report the discovery of significant X-ray polarization from the dynamically confirmed black hole X-ray binary (BHXB) GS 1354-64 during its 2025-2026 outburst, obtained with the Imaging X-ray Polarimetry Explorer (IXPE). The observation, obtained shortly after a bright X-ray flare, captures the source in an intermediate state following a stalled (failed) state transition. We discover significant 2-8 keV polarization at the ~4% level with high statistical support--14-sigma significance from frequentist analysis and log Bayes Factor 283+/-1 in a Bayesian framework--measuring PD 4.0+/-0.2% and PA-1+/-2 degrees (90% credible interval). The PD exhibits a statistically significant increasing trend with energy--the strongest such increase yet observed by IXPE in a BHXB--going from 2.1+/-0.3% in the 2-3 keV band to 11+/-3% in the 6.5-7 keV band, while the PA appears stable across both energy and time to within statistical uncertainties. Timing analysis of the IXPE data reveals a ~5 Hz Type-C quasi-periodic oscillation. IXPE + NuSTAR spectropolarimetric modeling suggests that the data can be described by polarized thermal disk and Comptonized components with PAs differing by ~90 degrees, or by a dominant Comptonized polarized component whose effective PD increases across the IXPE bandpass--the inferred component-level polarization levels are therefore model-dependent. In either picture, GS 1354-64 retains a strong coronal component during the transitional period observed by IXPE. These results illustrate how X-ray polarimetry can provide a sensitive diagnostic of the accretion state and geometry in black hole X-ray binary accretion flows, exploring a liminal phase at the cusp of state transition.
Discovery of energy-dependent phase variations in the polarization angle of Cen X-3
State Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所粒子天体物理国家重点实验室）；University of Chinese Academy of Sciences（中国科学院大学）；Department of Astronomy, University of Geneva（日内瓦大学天文系）
Discovery of minute-scale polarization angle rotation in a supermassive black hole jet
University of Crete（克里特大学）；Foundation for Research and Technology-Hellas（希腊研究与技术基金会）；The Pennsylvania State University（宾夕法尼亚州立大学）；Institute of Astrobiology, University of Crete（克里特大学天体生物学研究所）；Chalmers University of Technology（查尔姆斯理工大学）；Friedrich-Alexander Universität Erlangen-Nürnberg（埃尔朗根-纽伦堡弗里德里希·亚历山大大学）
Discovery of High X-Ray Polarization from the Neutron Star Low-Mass X-Ray Binary Cyg X-2 in the Horizontal Branch
Università degli Studi Roma Tre（罗马三分大学）；NASA Marshall Space Flight Center（美国国家航空航天局马歇尔太空飞行中心）；Massachusetts Institute of Technology（麻省理工学院）；University of Turku（图尔库大学）；INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；INAF–Istituto di Astrofisica e Planetologia Spaziali（意大利国家天体物理研究所天体物理学与行星科学研究所）
X-ray and Radio campaign of the Z-source GX 340+0: discovery of X-ray polarization and its implications
INAF-Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research（塔塔基础研究院天文与天体物理系）；MIT Kavli Institute for Astrophysics and Space Research（麻省理工学院卡弗里天体物理与空间研究所）；Massachusetts Institute of Technology（麻省理工学院）；Department of Physics, McGill University（麦吉尔大学物理系）；Trottier Space Institute, McGill University（麦吉尔大学特罗蒂尔太空研究所）；Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所粒子天体物理重点实验室）；Indian Institute of Astrophysics（印度天体物理研究所）；INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica（意大利国家天体物理研究所空间天体物理学与宇宙学研究所）；Department of Physics, Indian Institute of Technology Hyderabad（海德拉巴印度理工学院物理系）
Discovery of Two Highly Scattered Pulsars from Image-Based Circular Polarization Searches with the Australian SKA Pathfinder
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；Leibniz Universität Hannover（汉诺威莱布尼茨大学）；Center for Gravitation, Cosmology, and Astrophysics, Department of Physics, University of Wisconsin-Milwaukee（威斯康星大学密尔沃基分校物理系引力、宇宙学与天体物理中心）；CSIRO Space and Astronomy（澳大利亚联邦科学与工业研究组织空间与天文部）；Department of Physics and Astronomy, University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校物理与天文学系）；International Centre for Radio Astronomy Research, Curtin University（科廷大学国际射电天文研究中心）；Sydney Institute for Astronomy, School of Physic（悉尼天文学院，物理学院）
The High Time Resolution Universe Pulsar Survey -- XV: completion of the intermediate latitude survey with the discovery and timing of 25 further pulsars
Discovery of Two Consecutive Profile Change Events in the Millisecond Pulsar PSR J0437-4715
Macquarie University（麦考瑞大学）；Australia Telescope National Facility, CSIRO（澳大利亚望远镜国家设施，CSIRO）；OzGrav: The ARC Center of Excellence for Gravitational Wave Discovery（OzGrav：ARC引力波发现卓越中心）；Xinjiang Astronomical Observatory, Chinese Academy of Sciences（中国科学院新疆天文台）；School of Physics and Astronomy, Monash University（蒙纳士大学物理与天文学学院）
VLASS tidal disruption events with optical flares II: discovery of two TDEs with intermediate width Balmer emission lines and connections to the ambiguous extreme coronal line emitters
