X-ray spectroscopy of MXB 1728–34 with<i>XMM-Newton</i>

Egron, E.; Salvo, T. Di; Burderi, L.; Papitto, A.; Barragán, L.; Dauser, Robert C.; Wilms, J.; D’Aí, A.; Riggio, A.; Iaria, R.; Robba, N. R.

doi:10.1051/0004-6361/201016093

Cited by 35 publications

(44 citation statements)

References 47 publications

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“…The data analysis of the XMM/EPIC-pn spectrum was restricted to 2.4−11 keV to exclude the region around the detector Si K-edge (1.8 keV) and the mirror Au M-edge (2.3 keV) that could affect our analysis. This problem has already been noticed for the EPIC-pn observations performed in timing mode (e.g., D'Aì et al 2010;Papitto et al 2010;Egron et al 2011). The energy bands used for the other instruments are: 0.3−4 keV for the LECS, 1.8−10 keV for the MECS, 7−34 keV for HPGSPC, 15−200 keV for PDS onboard BeppoSAX, and 4−22 keV for PCA, and 15−100 keV for HEXTE onboard RXTE.…”

Section: Spectral Analysismentioning

confidence: 87%

Testing reflection features in 4U 1705−44 withXMM-Newton,BeppoSAX, and RXTE in the hard and soft states

Egron

Salvo

Motta

et al. 2013

A&A

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We use data from the bright atoll source 4U 1705−44 taken with XMM-Newton, BeppoSAX, and RXTE both in the hard and in the soft state to perform a self-consistent study of the reflection component in this source. Although the data from these X-ray observatories are not simultaneous, the spectral decomposition is shown to be consistent among the different observations, when the source flux is similar. We have therefore selected observations performed at similar flux levels in the hard and soft states to study the spectral shape in these two states in a broad-band (0.1−200 keV) energy range, with good energy resolution, and using self-consistent reflection models. These reflection models provide a good fit for the X-ray spectrum both in the hard and in the soft state in the whole spectral range. We discuss the differences in the main spectral parameters we find in both states, providing evidence that the inner radius of the optically thick disk slightly recedes in the hard state.

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Section: Spectral Analysismentioning

confidence: 87%

Testing reflection features in 4U 1705−44 withXMM-Newton,BeppoSAX, and RXTE in the hard and soft states

Egron

Salvo

Motta

et al. 2013

A&A

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“…From the reflection model fit, the inner disc radius and the source inclination were found to be ∼ 8 GM/c 2 and ∼ 28 deg., respectively. Thus, it is clear that the presence of absorption edges may mimic the broad iron line like feature or vice-versa (see also Egron et al 2011). …”

Section: Discussionmentioning

confidence: 99%

Broad-band X-ray emission and the reality of the broad iron line from the neutron star–white dwarf X-ray binary 4U 1820−30

Mondal

Dewangan

Pahari

et al. 2016

Mon. Not. R. Astron. Soc.

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Broad relativistic iron lines from neutron star X-ray binaries are important probes of the inner accretion disk. The X-ray reflection features can be weakened due to strong magnetic fields or very low iron abundances such as is possible in X-ray binaries with low mass, first generation stars as companions. Here we investigate the reality of the broad iron line detected earlier from the neutron star low mass X-ray binary 4U 1820-30 with a degenerate helium dwarf companion. We perform a comprehensive, systematic broadband spectral study of the atoll source using Suzaku and simultaneous NuSTAR & Swift observations. We have used different continuum models involving accretion disk emission, thermal blackbody and thermal Comptonization of either disk or blackbody photons. The Suzaku data show positive and negative residuals in the region of iron K band. These features are well described by two absorption edges at 7.67 ± 0.14 keV and 6.93 ± 0.07 keV or partial covering photoionized absorption or by blurred reflection. Though, the simultaneous Swift and NuSTAR data do not clearly reveal the emission or absorption features, the data are consistent with the presence of either absorption or emission features. Thus, the absorption based models provide an alternative to the broad iron line or reflection model. The absorption features may arise in winds from the inner accretion disk. The broadband spectra appear to disfavour continuum models in which the blackbody emission from the neutron star surface provides the seed photons for thermal Comptonization. Our results suggest emission from a thin accretion disk (kT disk ∼ 1 keV), Comptonization of disk photons in a boundary layer most likely covering a large fraction of the neutron star surface and innermost parts of the accretion disk, and blackbody emission (kT bb ∼ 2 keV) from the polar regions.

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“…Since reflection from the accretion disk is observed in LMXBs, we used the reflionx model (Ross & Fabian 2005), which models reflection by an optically thick atmosphere, which approximates the surface of an accretion disk well. In fact, the reflection model has recently been used in the analysis of other LMXBs (see Reis et al 2009;Egron et al 2011). The spectrum of the reflection depends on the abundance of iron relative to the solar value (Fe/solar).…”

Section: Bepposaxmentioning

confidence: 99%

ABeppoSAXandXMM-Newtonspectral study of 4U 1735-44

Mück

Piraino

Santangelo

2013

A&A

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Context. 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 K α line is found in several sources. Some of them show an asymmetric line profile as well, which could originate from relativistic effects. Aims. 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. Methods. 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. Results. 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.

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X-ray spectroscopy of MXB 1728–34 withXMM-Newton

Cited by 35 publications

References 47 publications

Testing reflection features in 4U 1705−44 withXMM-Newton,BeppoSAX, and RXTE in the hard and soft states

Testing reflection features in 4U 1705−44 withXMM-Newton,BeppoSAX, and RXTE in the hard and soft states

Broad-band X-ray emission and the reality of the broad iron line from the neutron star–white dwarf X-ray binary 4U 1820−30

ABeppoSAXandXMM-Newtonspectral study of 4U 1735-44

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