Discovery of cyclotron and narrow Fe K${}_{\alpha }$ lines in HMXB GRO J1750-27

Abstract

We report on timing and spectral analysis of transient Be X-ray pulsar GRO J1750-27 by using the Nuclear Spectroscopic Telescope Array (NuSTAR) observation from September 2021. This is the fourth outburst of the system since 1995. The NuSTAR observation was performed during the rising phase of the outburst. Pulsations at a period of 4.450710(1) s were observed in the 3-60 keV energy range. The average pulse profile comprised of a broad peak with a weak secondary peak which evolved with energy. We did not find any appreciable variation in the X-ray emission during this observation. The broad-band phase-averaged spectrum is described by a blackbody, a powerlaw or Comptonization component. We report discovery of Fe K${}_{\alpha }$ line at 6.4 keV along with presence of two cyclotron resonant scattering features around 36 and 42 keV. These lines indicate a magnetic field strength of $3.7_{-0.3}^{+0.1}\times 10^{12}$ and $4.4\pm 0.1\times 10^{12}$ G for the neutron star. We have estimated a source distance of $\sim$ 13.6-16.4 kpc based on the accretion-disc torque models.

arXiv comment8 pages, 9 Figures, 1 Table, Updated and accepted version for publication in MNRAS

References in corpus (27)

• On the Absorption of X-rays in the Interstellar Medium
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
• Broad-band gamma-ray and X-ray spectra of NGC 4151 and their implications for physical processes and geometry
• Observations of Accreting Pulsars
• The May 1989 outburst of the Soft X-ray Transient GS 2023+338 (V404 Cyg)
• Be/X-ray binaries
• The Swift/BAT Hard X-ray Transient Monitor
• Classical Be Stars: Rapidly Rotating B Stars with Viscous Keplerian Decretion Disks
• A natural explanation for periodic X-ray outbursts in Be/X-ray binaries
• A model for cyclotron resonance scattering features
• Magnetically Torqued Thin Accretion Disks
• On Timing and Spectral Characteristics of the X-ray Pulsar 4U 0115+63: Evolution of the Pulsation Period and the Cyclotron Line Energy
• Luminosity dependence of the cyclotron line and evidence for the accretion regime transition in V 0332+53
• Outbursts Large and Small from EXO 2030+375
• Phase dependent view of Cyclotron lines from model accretion mounds on Neutron Stars
• Orbital Decay and Evidence of Disk Formation in the X-ray Binary Pulsar OAO 1657-415
• Long-term change in the cyclotron line energy in Hercules X-1
• 4U 0115+63: phase lags and cyclotron resonant scattering
• Strong outburst activity of the X-ray pulsar X Persei during 2001-2011
• Cyclotron resonant scattering feature simulations. II. Description of the CRSF simulation process
• Pulse phase resolved spectroscopy of Vela X-1 with Suzaku
• Multiple cyclotron line-forming regions in GX 301-2
• NuSTAR discovery of a cyclotron absorption line in the transient X-ray pulsar 2S 1553-542
• The accretion powered spin-up of GRO J1750-27
• GROJ1750-27: a neutron star far behind the Galactic Center switching into the propeller regime
• Quiescent X-ray variability in the neutron star Be/X-ray transient GRO J1750-27

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• Cyclotron line formation in the radiative shock of an accreting magnetized neutron star
• The unaltered pulsar: GRO J1750-27, a super-critical X-ray neutron star that does not blink an eye
• AstroSat observation of the magnetar SGR J1830$-$0645 during its first detected X-ray outburst