Detection of the thermal component in GRB 160107A

TL;DR

This paper reports the detection of a thermal blackbody component in the emission of GRB 160107A, observed through combined data from multiple instruments, revealing insights into the burst's photospheric emission and emphasizing the importance of coordinated multi-instrument observations.

Contribution

First detection of a blackbody component in GRB 160107A using combined spectral data from CGBM and MAXI/GSC, highlighting the significance of multi-instrument observations.

Findings

Blackbody component detected with temperature ~1 keV

Prior emission observed ~45 seconds before main burst

Spectral data fit by blackbody plus power-law model

Abstract

We present the detection of a blackbody component in GRB 160107A emission by using the combined spectral data of the CALET Gamma-ray Burst Monitor (CGBM) and the MAXI Gas Slit Camera (GSC). The MAXI/GSC detected the emission $\sim$45 s prior to the main burst episode observed by the CGBM. The MAXI/GSC and the CGBM spectrum of this prior emission period is well fit by a blackbody with the temperature of $1.0^{+0.3}_{-0.2}$ keV plus a power-law with the photon index of $-1.6 \pm 0.3$. We discuss the radius to the photospheric emission and the main burst emission based on the observational properties. We stress the importance of the coordinated observations via various instruments collecting the high quality data over a broad energy coverage in order to understand the GRB prompt emission mechanism.