BeppoSAX and XMM-Newton spectral study of 4U 1735-44

Abstract

Low-mass X-ray binary systems consist of a neutron star and a main-sequence companion star. The compact object accretes matter via Roche-lobe overflow, which leads to an accretion disk. In addition to a broad-band continuum emission of a thermal component and a Comptonization part, evidence for a broad iron Kα line is found in several sources. Some of them show an asymmetric line profile as well, which could originate from relativistic effects. To understand the spectral behavior of the system 4U 1735-44, we study the broad-band spectrum and especially the iron line feature between 6.4 and 6.97 keV. The shape of the line allows one to determine the region where the line is produced. Together with the continuum models, a geometrical model of the source can be proposed. Furthermore, the effects of pile-up in the XMM-Newton observation are investigated. We analyzed data obtained with the X-ray satellites BeppoSAX and XMM-Newton. The XMM-Newton data were analyzed, specifically taking into account pile-up effects. With the help of the data of these two satellites, we performed a detailed spectral study in an energy range from 0.2-24 keV. During the observations, the source was in the so-called banana state of an atoll source. Fitting the BeppoSAX data, we found line features that we were able to model with a reflection model, whereas the continuum was modeled with a combination of a thermal component and a Comptonization part. The analysis of the XMM-Newton data gave evidence for a broad but not asymmetric iron line. We found no broadening or asymmetry of the line because of pile-up.

6 pages, 8 figures

References in corpus (9)

• Neutron Star Observations: Prognosis for Equation of State Constraints
• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
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• A relativistically smeared spectrum in the neutron star X-ray Binary 4U 1705-44: Looking at the inner accretion disc with X-ray spectroscopy
• Detection of the Irradiated Donor in the LMXBs 4U 1636-536 (=V801 Ara) and 4U 1735-444 (=V926 Sco)
• Testing reflection features in 4U 1705-44 with XMM-Newton, BeppoSAX and RXTE in the hard and soft state
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Cited by in corpus (1)

• NICER-NuSTAR Observations of the Neutron Star Low-Mass X-ray Binary 4U 1735-44