A relativistic iron emission line from the neutron star low-mass X-ray binary GX 3+1

Abstract

We present the results of a spectroscopic study of the Fe Kα emission of the persistent neutron-star atoll low-mass X-ray binary and type I X-ray burster GX 3+1 with the EPIC-PN on board XMM-Newton. The source shows a flux modulation over several years and we observed it during its fainter phase, which corresponds to an X-ray luminosity of Lx~10^37 ergs/s. When fitted with a two-component model, the X-ray spectrum shows broad residuals at \sim6-7 keV that can be ascribed to an iron Kα fluorescence line. In addition, lower energy features are observed at \sim3.3 keV, \sim3.9 keV and might originate from Ar XVIII and Ca XIX. The broad iron line feature is well fitted with a relativistically smeared profile. This result is robust against possible systematics caused by instrumental pile-up effects. Assuming that the line is produced by reflection from the inner accretion disk, we infer an inner disk radius of \sim25 Rg and a disk inclination of 35° < i < 44°.

4 pages, 3 figures Accepted for publication in Astronomy and Astrophysics

References in corpus (7)

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Cited by in corpus (17)

• The XMM-Newton view of the central degrees of the Milky Way
• NuSTAR Observations of the Accreting Atolls GX 3+1, 4U 1702-429, 4U 0614+091, and 4U 1746-371
• Testing reflection features in 4U 1705-44 with XMM-Newton, BeppoSAX and RXTE in the hard and soft state
• Suzaku broad-band spectrum of 4U 1705-44: Probing the Reflection component in the hard state
• NuSTAR and XMM-Newton broad-band spectrum of SAX J1808.4-3658 during its latest outburst in 2015
• Study of the reflection spectrum of the accreting neutron star GX 3+1 using XMM-Newton and INTEGRAL
• Study of the reflection spectrum of the LMXB 4U 1702-429
• Interstellar dust along the line of sight of GX 3+1
• A test of the nature of the Fe K Line in the neutron star low-mass X-ray binary Serpens X-1
• IGR J17451-3022: a dipping and eclipsing low mass X-ray binary
• Reflection component in the Bright Atoll Source GX 9+9
• High-frequency variability in neutron-star low-mass X-ray binaries
• The broadband spectral analysis of 4U 1702-429 using XMM-Newton and BeppoSAX data
• Study of the reflection spectrum of the bright atoll source GX 3+1 with NuSTAR
• Broadband observations of the X-ray burster 4U 1705-44 with BeppoSAX
• Accretion tori around rotating neutron stars I: Structure, shape and size
• BeppoSAX and XMM-Newton spectral study of 4U 1735-44