Burst Tails from SGR J1550-5418 Observed with Rossi X-ray Timing Explorer

TL;DR

This study identifies and analyzes long tail emissions following short bursts from magnetar SGR J1550-5418 using RXTE data, revealing thermal cooling spectra and comparing with other magnetars.

Contribution

It is the first extensive Bayesian analysis of long tails from SGR J1550-5418, providing detailed spectral and temporal characterization and a magnetar-based origin scenario.

Findings

Four long tails identified with durations from 13 seconds to over 3 kiloseconds.

Three tails exhibit thermal spectra with cooling trends.

Comparison with other magnetars suggests a common tail origin mechanism.

Abstract

We present the results of our extensive search using the Bayesian block method for long tails following short bursts from a magnetar, SGR J1550-5418, over all RXTE observations of the source. We identified four bursts with extended tails, most of which occurred during its 2009 burst active episode. The durations of tails range between ~13 s and over 3 ks, which are much longer than the typical duration of bursts. We performed detailed spectral and temporal analysis of the burst tails. We find that the spectra of three tails show a thermal nature with a trend of cooling throughout the tail. We compare the results of our investigations with the properties of four other extended tails detected from SGR 1900+14 and SGR 1806-20 and suggest a scenario for the origin of the tail in the framework of the magnetar model.