A2 Refereed review article in a scientific journal
Dense matter in neutron stars with eXTP
Authors: Li, Ang; Watts, Anna L.; Zhang, Guobao; Guillot, Sebastien; Xu, Yanjun; Santangelo, Andrea; Zane, Silvia; Feng, Hua; Zhang, Shuang-Nan; Ge, Mingyu; Qi, Liqiang; Salmi, Tuomo; Dorsman, Bas; Miao, Zhiqiang; Tu, Zhonghao; Cavecchi, Yuri; Zhou, Xia; Zheng, Xiaoping; Wang, Weihua; Cheng, Quan; Liu, Xuezhi; Wei, Yining; Wang, Wei; Xu, Yujing; Weng, Shanshan; Zhu, Weiwei; Li, Zhaosheng; Shao, Lijing; Tuo, Youli; Dohi, Akira; Lyu, Ming; Liu, Peng; Yuan, Jianping; Wang, Mingyang; Zhang, Wenda; Li, Zexi; Tao, Lian; Zhang, Liang; Shen, Hong; Providencia, Constanca; Tolos, Laura; Patruno, Alessandro; Li, Li; Liu, Guozhu; Zhou, Kai; Chen, Lie-Wen; Fan, Yizhong; Kajino, Toshitaka; Lai, Dong; Li, Xiangdong; Meng, Jie; Tang, Xiaodong; Xiao, Zhigang; Xiong, Shaolin; Xu, Renxin; Zhou, Shan-Gui; Ballantyne, David R.; Burgio, G. Fiorella; Chenevez, Jerome; Choudhury, Devarshi; Fantina, Anthea F.; Galloway, Duncan K.; Gulminelli, Francesca; Hebeler, Kai; Hoogkamer, Mariska; Horvath, Jorge E.; Kini, Yves; Kurkela, Aleksi; Linares, Manuel; Margueron, Jerome; Mendes, Melissa; Oertel, Micaela; Papitto, Alessandro; Poutanen, Juri; Rea, Nanda; Schwenk, Achim; Song, Xin-Ying; Svensson, Isak; Tsang, David; Vuorinen, Aleksi; Andersson, Nils; Miller, M. Coleman; Rezzolla, Luciano; Stone, Jirina R.; Thomas, Anthony W.
Publisher: Springer Science and Business Media LLC
Publication year: 2025
Journal:: SCIENCE CHINA Physics, Mechanics and Astronomy
Article number: 119503
Volume: 68
Issue: 11
ISSN: 1674-7348
eISSN: 1869-1927
DOI: https://doi.org/10.1007/s11433-025-2761-4
Web address : https://doi.org/10.1007/s11433-025-2761-4
In this white paper, we present the potential of the enhanced X-ray timing and polarimetry (eXTP) mission to constrain the equation of state of dense matter in neutron stars, exploring regimes not directly accessible to terrestrial experiments. By observing a diverse population of neutron stars-including isolated objects, X-ray bursters, and accreting systems-eXTP's unique combination of timing, spectroscopy, and polarimetry enables high-precision measurements of compactness, spin, surface temperature, polarimetric signals, and timing irregularity. These multifaceted observations, combined with advances in theoretical modeling, pave the way toward a comprehensive description of the properties and phases of dense matter from the crust to the core of neutron stars. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is planned to be launched in early 2030.
Funding information in the publication:
This work was supported by China’s Space Origins Exploration Program. Ang Li was supported by the National Natural Science Foundation of China (Grant No. 12273028). Anna L. Watts, Bas Dorsman, and Tuomo Salmi acknowledged support from ERC Consolidator (Grant No. 865768) AEONS. Anna L. Watts also acknowledged support from NWO grant ENW-XL OCENW.XL21.XL21.038. Sebastien Guillot acknowledged the support of the CNES. Shuang-Nan Zhang was supported by the National Natural Science Foundation of China (Grant No. 12333007), the International Partnership Program of Chinese Academy of Sciences (Grant No. 113111KYSB20190020), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100). Zhiqiang Miao was supported by the China National Postdoctoral Program for Innovation Talents (Grant No. BX20240223), and the China Postdoctoral Science Foundation Funded Project (Grant No. 2024M761948). Yuri Cavecchi acknowledged support from a Ramon y Cajal fellowship (Grant No. RYC2021-032718-1) financed by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR. Xia Zhou was supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region (Grant No. 2023D01E20), and the National SKA Program of China (Grant No. 2020SKA0120300). Xiaoping Zheng and Xuezhi Liu were supported by the National Natural Science Foundation of China (Grant Nos. 12033001, and 12473039), and Weihua Wang was supported by Zhejiang Provincial Natural Science Foundation of China (Grant No. LQ24A030002). Quan Cheng was supported by the National Natural Science Foundation of China (Grant No. 12003009). Weiwei Zhu was supported by the National SKA Program of China (Grant No. 2020SKA0120200), and the National Natural Science Foundation of China (Grant No. 12041303). Zhaosheng Li was supported by the National Natural Science Foundation of China (Grant No. 1227303). Lijing Shao was supported by the National SKA Program of China (Grant No. 2020SKA0120300), the Beijing Natural Science Foundation (Grant No. 1242018), and the Max Planck Partner Group Program funded by the Max Planck Society. Akira Dohi was supported by JSPS KAKENHI (the Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research) (Grant Nos. 23K19056, and 25K17403). Hong Shen was supported by the National Natural Science Foundation of China (Grant No. 12175109). Constançã Providência acknowledged support from FCT (Fundação para a Ciência e a Tecnologia, I.P., Portugal) (Grant Nos. UIDB/04564/2020, and 2022.06460.PTDC). Laura Tolos was supported from the program Unidad de Excelencia María de Maeztu CEX2020-001058-M, from the project PID2022-139427NB-I00 financed by the Spanish MCIN/AEI/10.13039/501100011033/FEDER, UE (FSE+), and by the CRC-TR 211 “Strong-interaction matter under extreme conditions”–project Nr. 315477589–TRR 211. Alessandro Patruno acknowledged support from grant PID2021-124581OB-I0, PID2024-155316NB-I00, and 2021SGR00426. Li Li was supported by the National Natural Science Foundation of China (Grant No. 12122513). The work of Kai Hebeler, Melissa Mendes, Achim Schwenk, and Isak Svensson was supported in part by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant No. 101020842), and by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)–Project-ID 279384907–SFB 1245. Manuel Linares acknowledged support from the ERC Consolidator ( Grant No. 101002352) (LOVENEST). Nanda Rea was supported by the European Research Council (ERC) via the Consolidator Grant “MAGNESIA” (Grant No. 817661) and the Proof of Concept “DeepSpacePulse” (Grant No. 101189496), the Catalan grant SGR2021-01269, the Spanish grant ID2023-153099NA-I00, and the program Unidad de Excelencia Maria de Maeztu CEX2020-001058-M. Aleksi Vuorinen was supported by the Research Council of Finland (Grant No. 354533).
