A spectral study of the black hole X-ray binary MAXI J1820+070 with AstroSat and NuSTAR

Abstract

MAXI J1820+070 is a newly discovered transient black hole X-ray binary, which showed several spectral and temporal features. In this work, we analyse the broadband X-ray spectra from all three simultaneously observing X-ray instruments onboard AstroSat, as well as contemporaneous X-ray spectra from NuSTAR, observed during the hard state of MAXI J1820+070 in March 2018. Implementing a combination of multi-colour disc model, relativistic blurred reflection model relxilllpCp and a distant reflection in the form of xillverCp, we achieve reasonable and consistent fits for AstroSat and NuSTAR spectra. The best-fit model suggests a low temperature disc ($k{T}_{\mathrm{in}}\sim 0.3$ keV), iron overabundance ($A_{\mathrm{Fe}}\sim 4-5$ solar), a short lamp-post corona height ($h\lesssim 8R_{\mathrm{g}}$), and a high corona temperature ($k{T}_{\mathrm{e}}\sim 115-150$ keV). Addition of a second Comptonisation component leads to a significantly better fit, with the $k{T}_{\mathrm{e}}$ of the second Comptonisation component being $\sim 14-18$ keV. Our results from independent observations with two different satellites in a similar source state indicate an inhomogeneous corona, with decreasing temperature attributed to increasing height. Besides, utilising the broader energy coverage of AstroSat, we estimate the black hole mass to be $6.7-13.9M_{\odot }$, consistent with independent measurements reported in the literature.

References in corpus (13)

• X-ray Properties of Black-Hole Binaries
• Modelling the behaviour of accretion flows in X-ray binaries
• The role of the reflection fraction in constraining black hole spin
• The corona contracts in a black-hole transient
• A radio parallax to the black hole X-ray binary MAXI J1820+070
• AstroSat/LAXPC reveals the high energy variability of GRS 1915+105 in the chi class
• Reflection Spectra of the Black Hole Binary Candidate MAXI J1535-571 in the Hard State Observed by NuSTAR
• The Soft State of the Black Hole Transient Source MAXI J1820+070: Emission from the Edge of the Plunge Region?
• An in-depth study of a neutron star accreting at low Eddington rate: On the possibility of a truncated disk and an outflow
• Accretion geometry of the black-hole binary Cygnus X-1 from X-ray polarimetry
• Broadband reflection spectroscopy of MAXI J1535-571 using AstroSat: Estimation of black hole mass and spin
• A Black Hole X-ray Binary at $\sim$100 Hz: Multiwavelength Timing of MAXI J1820+070 with HiPERCAM and NICER
• Unveiling the temporal properties of MAXI J1820+070 through AstroSat observations

Cited by in corpus (19)

• Accretion Geometry in the Hard State of the Black-Hole X-Ray Binary MAXI J1820+070
• NuSTAR monitoring of MAXI J1348-630: evidence of high density disc reflection
• A timing-based estimate of the spin of the black hole in MAXI J1820+070
• Chasing the break: Tracing the full evolution of a black hole X-ray binary jet with multi-wavelength spectral modeling
• Illumination of the accretion disk in black hole binaries: An extended jet as the primary source of hard X-rays
• Accretion Scenario of MAXI J1820+070 during 2018 Outbursts with Multi-mission Observations
• The accretion/ejection link in the neutron star X-ray binary 4U 1820-30 I: A boundary layer-jet coupling?
• A multi-wavelength study of the hard and soft states of MAXI J1820+070 during its 2018 outburst
• Gamma-ray observations of MAXI J1820+070 during the 2018 outburst
• Accreting on the edge: a luminosity-dependent cyclotron line in the Be/X-ray Binary 2S 1553-542 accompanied by accretion regimes transition
• AstroSat view of the neutron star low-mass X-ray binary GX 340+0
• Spectral and Temporal Studies of Swift\,J1658.2--4242 using {\it AstroSat} Observations with {\tt JeTCAF} Model
• Science with the $AstroSat$ Soft X-ray Telescope: an overview
• The 2018 outburst of MAXI J1820+070 as seen by Insight-HXMT
• Intermittent QPO properties of MAXI J1820+070 revealed by Insight-HXMT
• LAXPC instrument onboard AstroSat: Five exciting years of new scientific results specially on X-ray Binaries
• Investigating the consistency of the shape and flux of X-ray reflection spectra in the hard state with an accretion disk reaching close to the black hole
• Interaction between disk and extended corona in a general relativistic framework
• Tracking the evolution of the accretion flow in MAXI J1820+070 during its hard state with the JED-SAD model