X-Ray Intraday Variability of the Blazar OJ 287 Observed with XMM-Newton

TL;DR

This study analyzes X-ray intraday variability of the blazar OJ 287 over multiple years, revealing cospatial emission regions and the influence of particle acceleration and cooling mechanisms.

Contribution

First detailed intraday X-ray variability analysis of OJ 287 across multiple epochs with spectral and timing insights.

Findings

Low amplitude variability observed in most light curves.

Soft and hard X-ray emissions are cospatial.

Red noise dominates the power spectral densities.

Abstract

We present X-ray intraday variability, cross-correlated variability, and power spectrum density analysis of the binary black hole blazar candidate OJ 287. The X-ray pointed observations of the source were carried out on eight occasions by the EPIC-pn camera on board the XMM-Newton satellite from November 2005 to November 2022. These good time intervals range between 3.6 hours and 24.1 hours. Three energy bands -- 0.2-2 keV (soft), 2-10 keV (hard), and 0.2-10 keV (total) -- have been used to estimate variability. Low amplitude variations are observed in 4, 5, and 6 light curves in soft, hard, and total energy bands, respectively. Only two observation IDs has shown variation in the all energy bands. The discrete correlation function of the light curves in soft and hard energy bands peaks at zero lag, suggesting that the emission in both bands was cospatial and came from the same population of leptons. Red noise dominates the power spectral densities of variable light curves. According to our flux and spectrum investigations, both particle acceleration and synchrotron cooling mechanisms contribute significantly to the emission from this blazar.