Broadband spectroscopy of the eclipsing high mass X-ray binary 4U 1700-37 with Suzaku

Abstract

We present the results obtained from broadband spectroscopy of the high mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant and rapid variation in source flux during entire observation. We did not find any signature of pulsations in the light curves. However, a quasi-periodic oscillation at ~20 mHz was detected in the power density spectrum of the source. The 1-70 keV spectrum was fitted with various continuum models. However, we found that the partially absorbed high energy cutoff power-law and Negative and Positive power-law with Exponential cutoff (NPEX) models described the source spectrum well. Iron emission lines at 6.4 keV and 7.1 keV were detected in the source spectrum. An absorption like feature at ~39 keV was detected in the residuals while fitting the data with NPEX model. Considering the feature as cyclotron absorption line, the surface magnetic field of the neutron star was estimated to be ~3.4 times 10^12 Gauss. To understand the cause of rapid variation in the source flux, time-resolved spectroscopy was carried out by dividing the observation into 20 narrow segments. The results obtained from the time-resolved spectroscopy are interpreted as the accretion of inhomogeneously distributed matter in the stellar wind of the supergiant companion star as the cause of observed flux variation in 4U 1700-37. A sharp increase in column density after ~0.63 orbital phase indicates the presence of an accretion wake that blocks the continuum and produces the eclipse like low-flux segment.

9 pages, 7 figures; Accepted for publication in MNRAS

References in corpus (6)

• Thermal and Bulk Comptonization in Accretion-Powered X-Ray Pulsars
• High variability in Vela X-1: giant flares and off states
• Timing and Spectral properties of Be/X-ray pulsar EXO 2030+375 during a Type I outburst
• Short-Term Variability of X-rays from Accreting Neutron Star Vela X-1: I. Suzaku Observations
• Variations in the pulsation and spectral characteristics of OAO 1657-415
• Possible detection of a cyclotron resonance scattering feature in the X-ray pulsar 4U 1909+07

Cited by in corpus (14)

• Cyclotron lines in highly magnetized neutron stars
• The impact of companions on stellar evolution
• X-ray reprocessing: Through the eclipse spectra of high mass X-ray binaries with XMM-Newton
• AstroSat Observations of the first Galactic ULX Pulsar Swift J0243.6+6124
• Numerical simulations and infrared spectro-interferometry reveal the wind collision region in gamma2 Velorum
• X-Ray Spectra of The High-Mass X-RAY Binary 4U~1700-37 using BeppoSAX, Suzaku and RXTE Observations
• Probing the Cyclotron line characteristics of 4U 1538-522 using AstroSat-LAXPC
• NuSTAR view of Be/X-ray binary pulsar 2S 1417-624 during 2018 giant outburst
• New Constraints on the Geometry and Kinematics of Matter Surrounding the Accretion Flow in X-ray Binaries from $Chandra$ HETG X-ray Spectroscopy
• Timing and Spectral Analysis of HMXB OAO 1657-415 with NuSTAR
• Torque reversal and cyclotron absorption feature in HMXB 4U 1538-522
• Possible detection of a new cyclotron feature in 4U 1700-37
• AstroSat observations of eclipsing high mass X-ray binary pulsar OAO 1657-415
• On The Nature of Einstein Probe Transient EP250916a: Insights from X-ray, Optical, and Radio Observations