X-ray Flux and Spectral Variability of Blazar H 2356-309

TL;DR

This study analyzes X-ray timing and spectral data of blazar H 2356-309 over several years, finding low flux variability, no intra-day spectral changes, and spectral curvature described by log parabolic and power law models.

Contribution

It provides detailed spectral modeling and variability analysis of H 2356-309 using multiple observations, highlighting the spectral curvature and stability over intra-day timescales.

Findings

Moderate flux variability with 1.7-2.2% amplitude.

No intra-day variability detected.

Spectral curvature well described by log parabolic and power law models.

Abstract

We present the results of timing and spectral analysis of the blazar H 2356-309 using XMM-Newton observations. This blazar is observed during 13 June 2005-24 December 2013 in total nine observations. Five of the observations show moderate flux variability with amplitude 1.7-2.2 percent. We search for the intra-day variability timescales in these five light curves, but did not find in any of them. The fractional variability amplitude is generally lower in the soft bands than in the hard bands, which is attributed to the energy dependent synchrotron emission. Using the hardness ratio analysis, we search for the X-ray spectral variability along with flux variability in this source. However, we did not find any significant spectral variability on intra-day timescales. We also investigate the X-ray spectral curvature of blazar H 2356-309 and found that six of our observations are well described by the log parabolic model with alpha=1.99-2.15 and beta=0.03-0.18. Three of our observations are well described by power law model. The break energy of the X-ray spectra varies between 1.97-2.31 keV. We investigate the correlation between various parameters that are derived from log parabolic model and their implications are discussed.