Soft X-ray Observation of the Prompt Emission of GRB100418A

TL;DR

This paper reports on the early X-ray observations of GRB100418A, revealing a low peak energy and confirming its consistency with known gamma-ray burst relations, providing insights into its emission properties.

Contribution

First detailed X-ray observation of GRB100418A capturing its prompt emission with spectral analysis and relation verification.

Findings

The GRB has a very low peak energy ($E_p \,\leq\ 8.3$ keV).

The light curve fits a power law plus exponential decay.

The burst satisfies the Yonetoku and is consistent with the Amati relation.

Abstract

We have observed the prompt emission of GRB100418A, from its beginning by the MAXI/SSC (0.7-7 keV) on board the International Space Station followed by the Swift/XRT (0.3-10 keV) observation. The light curve can be fitted by a combination of a power law component and an exponential component (decay constant is $31.6\pm 1.6$ sec). The X-ray spectrum is well expressed by the Band function with $E_{\rm p}\leq$8.3 keV. This is the brightest GRB showing a very low value of $E_{\rm p}$. It satisfies the Yonetoku-relation ($E_{\rm p}$-$L_{\rm p}$). It is also consistent with the Amati relation ($E_{\rm p}$-$E_{\rm iso}$) in 2.5$\sigma$ level.