Time properties of the the rho-class burst of the microquasar GRS 1915+105 observed with BeppoSAX in April 1999

TL;DR

This study analyzes the timing properties of the rho-class bursting activity in GRS 1915+105 using BeppoSAX data, confirming correlations between burst recurrence time, count rate, and hard X-ray delay, and revealing two parallel recurrence time branches.

Contribution

It extends previous findings by demonstrating the existence of two parallel recurrence time branches in the rho class of GRS 1915+105.

Findings

Recurrence times correlate with count rate and hard X-ray delay.

Recurrence times are distributed along two parallel branches.

The difference between the two branches is approximately 5.2 seconds.

Abstract

We present a temporal analysis of a BeppoSAX observation of GRS 1915+105 performed on April 13, 1999 when the source was in the rho class, which is characterised by quasi-regular bursting activity. The aim of the present work is to confirm and extend the validity of the results obtained with a BeppoSAX observation performed on October 2000 on the recurrence time of the burst and on the hard X-ray delay. We divided the entire data set into several series, each corresponding to a satellite orbit, and performed the Fourier and wavelet analysis and the limit cycle mapping technique using the count rate and the average energy as independent variables. We found that the count rates correlate with the recurrence time of bursts and with hard X-ray delay, confirming the results previously obtained. In this observation, however, the recurrence times are distributed along two parallel branches with a constant difference of 5.2+/-0.5 s.