Aims. Soft X-ray excesses have been detected in several Be/X-ray binaries and interpreted as the signature of hard X-ray reprocessing in the inner accretion disk. The system XMMU J054134.7-682550, located in the LMC, featured a giant Type II outburst in August 2007. The geometry of this system can be understood by studying the response of the soft excess emission to the hard X-ray pulses.
Methods. We have analyzed series of simultaneous observations obtained with XMM-Newton/EPIC-MOS and RXTE/PCA in order to derive spectral and temporal characteristics of the system, before, during and after the giant outburst. Spectral fits were performed and a timing analysis has been carried out. Spectral variability, spin period evolution and energy dependent pulse shapes are analysed.
Results. The outburst (L_X = 3* 10^38 erg/s \approx L_EDD) spectrum could be modeled successfully using a cutoff powerlaw, a cold disk emission, a hot blackbody, and a cyclotron absorption line. The magnetic field and magnetospheric radius could be constrained. The thickness of the inner accretion disk is broadened to a width of 75 km. The hot blackbody component features sinusoidal modulations indicating that the bulk of the hard X-ray emission is emitted preferentially along the magnetic equator. The spin period of the pulsar decreased very significantly during the outburst. This is consistent with a variety of neutron star equations of state and indicates a very high accretion rate.
Searching for optical pulsations from spider millisecond pulsars with the fast photometer SiFAP2
INAF Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);Dipartimento di Fisica, Sapienza Università di Roma(罗马智慧大学物理系);Institute of Space Sciences (ICE, CSIC)(空间科学研究所(西班牙高等科学研究理事会));Institut d’Estudis Espacials de Catalunya (IEEC)(加泰罗尼亚太空研究学院);INAF - Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);ASI - Agenzia Spaziale Italiana(意大利航天局);Department of Physics, Norwegian University of Science and Technology(挪威科技大学物理系)
A deep X-ray and UV look into the reflaring stage of the accreting millisecond pulsar SAX J1808.4-3658
INAF - Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);Sapienza Università di Roma(罗马第一大学);ASI - Agenzia Spaziale Italiana(意大利航天局);INAF - Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);Università di Palermo(巴勒莫大学);Dipartimento di Fisica e Chimica - Emilio Segrè, Università di Palermo(巴勒莫大学埃米利奥·塞格雷物理化学系);Dipartimento di Fisica, Università degli Studi di Cagliari(卡利亚里大学物理系);INAF/IASF Palermo(意大利国家天体物理研究所帕勒莫空间物理研究所);Institute of Space Sciences (ICE, CSIC)(空间科学研究所(西班牙高等科学研究委员会));Institut d’Estudis Espacials de Catalunya (IEEC)(加泰罗尼亚空间研究学院)
Energy-resolved pulse profiles of Vela X-1: cross-calibrating XMM-Newton and NuSTAR to trace spectral features
INAF - IASF Palermo(意大利国家天体物理研究所帕勒莫天文物理研究所);Università degli Studi di Palermo(巴勒莫大学);European Space Agency (ESA)(欧洲航天局);University of Geneva(日内瓦大学);INAF, Osservatorio Astronomico di Brera(意大利国家天体物理研究所布里拉天文台);Friedrich-Alexander-Universität Erlangen-Nürnberg(埃尔朗根-纽伦堡大学);Anton Pannekoek Institute for Astronomy, University of Amsterdam(阿姆斯特丹大学安东·潘内克克天文学研究所)
Spin-down of the accreting magnetar candidate 4U 0114+65: possible first evidence for a strong coupling regime
Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Universidad de Alicante(阿利坎特大学应用物理科学与技术大学研究所);Sternberg Astronomical Institute, Moscow M.V. Lomonosov State University(莫斯科罗蒙诺索夫国立大学斯特恩伯格天文研究所);Institute for Physics and Astronomy, Universität Potsdam(波茨坦大学物理与天文学研究所)
Pulse profile variations in the accreting X-ray pulsar Vela X-1
Center for Space Science and Technology, University of Maryland, Baltimore County(马里兰大学巴尔的摩县分校空间科学与技术中心);Center for Research and Exploration in Space Science and Technology, NASA/Goddard Space Flight Center(NASA戈达德太空飞行中心空间科学与技术研究探索中心);School of Physics and Centre for Space Research, University College Dublin(都柏林大学学院物理系与空间研究中心);European Space Agency (ESA), European Space Astronomy Centre (ESAC)(欧洲空间局(ESA)欧洲空间天文中心(ESAC));European Space Agency (ESA), European Space Research and Technology Centre (ESTEC)(欧洲空间局(ESA)欧洲空间研究与技术中心(ESTEC));Huygens-Kamerlingh Onnes Laboratory, Leiden University(莱顿大学惠更斯-卡末林·昂内斯实验室);Departamento de Física, Universidad de Santiago de Chile(智利圣地亚哥大学物理系);Center for Interdisciplinary Research in Astrophysics and Space Exploration (CIRAS), USACH(智利圣地亚哥天主教大学跨学科天体物理学与空间探索研究中心(CIRAS))
Xiangtan University(湘潭大学);Xinjiang Astronomical Observatory, Chinese Academy of Sciences(中国科学院新疆天文台);Nanjing Normal University(南京师范大学);National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台)
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)
Double-hump spectrum, pulse profile dip, and pulsed fraction spectra from the low-accretion regime in the X-ray pulsar MAXI J0655-013
INAF-Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);Department of Astronomy and Astrophysics, University of California, San Diego(加州大学圣地亚哥分校天文学与天体物理学系);INAF - IASF Palermo(意大利国家天体物理研究所巴勒莫天文物理研究所);Institut für Astronomie und Astrophysik, Universität Tübingen(蒂宾根大学天文与天体物理研究所);Department of Physics and Astronomy, Howard University(霍华德大学物理与天文学系);CRESST and NASA Goddard Space Flight Center, Astrophysics Science Division(NASA戈达德太空飞行中心天体物理学科学部 CRESST);European Space Agency (ESA), European Space Astronomy Centre (ESAC)(欧洲空间局欧洲空间天文中心)
Constraints on cyclotron features and accretion regime in the high-mass X-ray binary 4U 1700-37 from NuSTAR
Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata(拉普拉塔国立大学天体物理与地球物理科学学院);Instituto Argentino de Radioastronomía (CCT La Plata, CONICET(阿根廷射电天文研究所);CICPBA(加那利群岛天体物理研究所);UNLP)(拉古纳大学天体物理学系);Instituto de Astrofísica de Canarias (IAC)(哈恩大学物理系);Departamento de Astrofísica, Universidad de La Laguna(哈恩大学机械与矿业工程系);Departamento de Física (EPS), Universidad de Jaén;Departamento de Ingeniería Mecánica y Minera (EPSJ), Universidad de Jaén
Pulse profile modelling of the 2024 outburst of the accreting millisecond pulsar SRGA J144459.2-604207
Anton Pannekoek Institute for Astronomy, University of Amsterdam(阿姆斯特丹大学安顿·潘内科克天文学研究所);University of Helsinki(赫尔辛基大学);Gravitation and Astroparticle Physics Amsterdam (GRAPPA), University of Amsterdam(阿姆斯特丹引力与高能物理研究所(GRAPPA));McGill University(麦吉尔大学);Trottier Space Institute, McGill University(麦吉尔大学特罗蒂尔太空研究所);University of Turku(图尔库大学);INAF Istituto di Astrofisica e Planetologia Spaziali(意大利国家天体物理学研究所);Monash University(蒙纳士大学);Institute for Globally Distributed Open Research and Education (IGDORE)(全球分布式开放研究与教育研究所);University of Toulouse(图卢兹大学);Università degli Studi di Roma “Tor Vergata”(罗马托维加塔大学);Newcastle University(纽卡斯尔大学);INAF Osservatorio Astronomico di Roma(意大利国家天体物理学研究所罗马天文台);Nanjing University(南京大学);Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education(教育部现代天体学与天体物理学重点实验室(南京大学))
Two sides of the same spin: tracking optical and radio pulsations of SAX J1808.4-3658 from outburst to quiescence
INAF - Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);Sapienza Università di Roma(罗马第一大学);ASI - Agenzia Spaziale Italiana(意大利航天局);INAF - Osservatorio Astronomico di Cagliari(意大利国家天体物理研究所卡利亚里天文台);INAF – Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);Institute of Space Sciences (ICE, CSIC)(空间科学研究所(西班牙高等科学研究委员会));Institut d’Estudis Espacials de Catalunya (IEEC)(加泰罗尼亚空间研究学院)