Detecting emission lines with XMM-Newton in 4U 1538-52

Abstract

Context. The properties of the X-ray emission lines are a fundamental tool for studying the nature of the matter surrounding the neutron star and the phenomena that produce these lines. Aims. The aim of this work is to analyze the X-ray spectrum of 4U 1538-52 obtained by the XMM-Newton observatory and to look for the presence of diagnostic lines in the energy range 0.3-11.5 keV. Methods. We used a 54 ks PN & MOS/XMM-Newton observation of the high mass X-ray binary 4U 1538-52 covering the orbital phase between 0.75 to 1.00 (the eclipse-ingress). We have modelled the 0.3-11.5 keV continuum emission with three absorbed power laws and looked for the emission lines. Results. We found previously unreported recombination lines, in this system, at 2.4 keV, 1.9 keV and 1.3 keV, consistent with the presence of highly ionized states of S XV He?, Si XIII He? and Mg K? or Mg XI He?. On the other hand, both out of eclipse and in eclipse we detect a fluorescence iron emission line at 6.4 keV which is resolved into two components: a narrow ($\sigma \le$ 10 eV) fluorescence Fe K? line plus one hot line from highly photoionized Fe XXV. Conclusions. The detection of new recombination lines during eclipse-ingress in 4U 1538-52 indicates that there is an extended ionized region surrounding the neutron star.

arXiv comment11 pages, 6 figures, accepted for publication in Astronomy and Astrophysics

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Cited by in corpus (13)

• An XMM-Newton view of FeKα in HMXBs
• A Clumpy Stellar Wind and Luminosity-Dependent Cyclotron Line Revealed by The First Suzaku Observation of the High-Mass X-ray Binary 4U 1538-522
• The accretion environment in Vela X-1 during a flaring period using XMM-Newton
• X-ray reprocessing: Through the eclipse spectra of high mass X-ray binaries with XMM-Newton
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• Absorption features caused by oscillations of electrons on the surface of a quark star
• Energy levels, radiative rates and electron impact excitation rates for transitions in Be-like Ti XIX
• Orbital phase resolved spectroscopy of 4U1538-52 with MAXI
• Torque reversal and cyclotron absorption feature in HMXB 4U 1538-522
• Cen x-3 as seen by MAXI during six years
• Discussing the physical meaning of the absorption feature at 2.1 keV in 4U 1538-52
• Exploring polarization and geometry in the X-ray pulsar 4U 1538-52
• Spectroscopic modelling of two high-mass X-ray binaries, Cyg X--3 and 4U 1538--522