Spectroscopic modelling of four neutron star low-mass X-ray binaries using CLOUDY

Abstract

Low-mass X-ray binaries (LMXBs) have a wide range of X-ray properties which can be utilised to reveal many physical conditions of the associated accretion discs. We use the spectral synthesis code CLOUDY to perform a detailed modelling of neutron star LMXBs GX 13+1, MXB 1659--298, 4U 1323--62 and XB 1916--053; and characterise the underlying physical conditions, such as density, radiation field, metallicity, wind velocity, etc. For this purpose we model highly ionised spectra of Fe, Ca, S, Si, Mg, Al in the soft X-ray band, and compare the predicted line flux ratios with the observed values. We also find that the strength and profile of these spectral lines get modified in the presence of magnetic field in the accretion disc. Using this, we estimate an upper limit of the existing magnetic field to be about a few hundred to a few thousand G in the accretion discs of these four LMXBs.

Accepted for publication in MNRAS, 11 pages, 9 tables and 10 figures

References in corpus (5)

• The 2013 Release of Cloudy
• Disk-Jet Coupling in Black Hole Accretion Systems I: General Relativistic Magnetohydrodynamical Models
• Average hard X-ray emission from NS LMXBs: Observational evidence of different spectral states in NS LMXBs
• Polarised infrared emission from X-ray binary jets
• Chandra X-ray spectroscopy of a clear dip in GX 13+1

Cited by in corpus (2)

• Probing the tidal disruption event iPTF16axa with CLOUDY and disc-wind models
• Spectroscopic modelling of two high-mass X-ray binaries, Cyg X--3 and 4U 1538--522