A timing-based estimate of the spin of the black hole in MAXI J1820+070

TL;DR

This paper estimates the spin of the black hole in MAXI J1820+070 using timing analysis of X-ray variability, applying the Relativistic Precession Model to NICER observations to derive a precise spin value.

Contribution

It provides a novel timing-based estimate of the black hole's spin using PDS modeling and the Relativistic Precession Model, improving spin measurement accuracy.

Findings

Black hole spin estimated at 0.799^{+0.016}_{-0.015}

Characteristic frequencies modeled with PDS components

Application of the Relativistic Precession Model to X-ray timing data

Abstract

MAXI J1820+070 (ASSASN-18ey) is a Black hole X-ray binary discovered in 2018. The brightness of the source triggered multi-wavelength campaigns of this source from different observatories. We analyse the Power Density Spectra obtained from NICER high cadence observations of the source in the hard state. We obtain the evolution of the characteristic frequencies by modelling the PDS. We interpret the characteristic frequencies of various PDS components (both QPOs and broad band noise components) as variability occurring at a particular radius, and explain them in the context of the Relativistic Precession Model. We estimate the dimensionless spin of the black hole at $0.799^{+0.016}_{-0.015}$ by fitting the Relativistic Precession Model.