Properties of MAXI J1348-630 during Its Second Outburst in 2019

TL;DR

This paper analyzes the second outburst of the galactic black hole candidate MAXI J1348-630 in 2019, revealing it was a 'failed' outburst with the source remaining in the hard state, characterized by non-thermal dominance and shock features.

Contribution

It provides a detailed spectral and temporal analysis of the second outburst using multi-satellite data, highlighting its unique 'failed' nature and spectral properties.

Findings

Outburst lasted about two and a half months.

Source remained in the hard spectral state throughout.

Weak reflection and low-frequency QPOs were detected.

Abstract

The newly discovered galactic black hole candidate (BHC) MAXI~J1348-630 showed two major outbursts in 2019, just after its discovery. Here, we provide a detailed spectral and temporal analysis of the less-studied second outburst using archive data from multiple satellites, namely Swift, MAXI, NICER, NuSTAR and AstroSat. The outburst continued for around two and a half months. Unlike the first outburst from this source, this second outburst was a `failed' one. The source did not transition to soft or intermediate spectral states. During the entire outburst, the source was in the hard state with high dominance of non-thermal photons. The presence of strong shocks are inferred from spectral fitting using a TCAF model. In NuSTAR spectra, weak reflection is observed from spectral fitting. Low-frequency quasi-periodic oscillations are also detected in AstroSat data.