<i>NuSTAR</i> and <i>Swift</i> observations of the extragalactic black hole X-ray binaries

We present the results obtained from detailed spectral and timing studies of extra-galactic black hole X-ray binaries LMC~X--1 LMC~X--3, using simultaneous observations with {\it Nuclear Spectroscopic Telescope Array (NuSTAR)} Neil Gehrels Swift} observatories. The combined spectra in $0.5-30$~keV energy range, between 2014 2019, are investigated for both sources. do not find any noticeable variability light curves, $0.1-10$~Hz fractional rms estimated to be $<2$\%. No evidence quasi-periodic oscillations is found power density spectra. sources high soft state during disc temperature $T_{\rm in}\sim 1$~keV, photon index, $\Gamma > 2.5$ thermal emission fraction, $f_{\rm disc}>80$\%. An Fe K$\alpha$ line detected LMC~X--1, though no such feature observed LMC~X--3. From modelling, spins holes LMC~X--3 range $0.92-0.95$ $0.19-0.29$, respectively. accretion efficiency be, $\eta \sim 0.13$ 0.04$