Accretion Flow Evolution of a New Black Hole Candidate MAXI J1348–630 during the 2019 Outburst
Arghajit Jana, Dipak Debnath, Debjit Chatterjee, Kaushik Chatterjee, Sandip Kumar Chakrabarti, Sachindra Naik, Riya Bhowmick, Neeraj Kumari
Abstract
Abstract Galactic black hole (BH) candidate MAXI J1348–630 was recently discovered by MAXI and Swift/BAT satellites during its first outburst in 2019 January, which continued for ∼4 months. We study the spectral and timing properties of the source in detail. The combined 1–150 keV Swift/XRT, Swift/BAT, and MAXI/GSC spectra are investigated with the two-component advective flow (TCAF) solution. Physical flow parameters of TCAF, such as the Keplerian disk accretion rate, the sub-Keplerian halo accretion rate, the shock location, and the shock compression ratio, are estimated from our spectral fits. Based on the variation of flux in soft and hard X-ray ranges, the hardness ratio, TCAF model fitted accretion rates, and the accretion rate ratio, we show how the source evolved through four spectral states, viz., hard, hard-intermediate, soft-intermediate, and soft, in rising and declining states. Low-frequency quasi-periodic oscillations are observed in two observations during the rising phase of the outburst. From the spectral analysis, we estimate the mass of the BH to be M ⊙ . We also find that the viscous timescale in this outburst is ∼3.5 days. The distance of the source is also estimated as 5–10 kpc from state transition luminosity.