High energy properties of PKS 1830-211

Abstract

We report on an analysis of X- and $γ$-ray observations of PKS 1830-211, based on the long-term campaigns carried out by \emph{INTEGRAL} and COMPTEL. The \emph{INTEGRAL} data currently available present a $33σ$ significance detection in the 20-100 keV band, while the COMPTEL 6-years data provide a $5.2σ$ significance detection in the 1-3 MeV energy band. At hard X-rays, \emph{INTEGRAL} and supplementary \emph{SWIFT} observations show flux variability on timescales of months. At $γ$-rays, the source shows persistent emission over years. The hard X-ray spectrum is well represented by a power-law model, with $Γ\sim 1.3$ in the 20-250 keV band. This photon index is well consistent with the previous report of $Γ\sim 1.3$ obtained at $E > 3.5$ keV from the best fit of \emph{XMM-Newton} data with a broken power law model. The joint \emph{XMM-Newton}/\emph{INTEGRAL} spectrum presented here is then fit with a broken power-law model and the parameters are refined compared to the previous. The results show the photon index changes from $\sim 1.0$ to $\sim 1.3$ at a break energy $\sim 4$ keV. At MeV energies, the spectrum softens to $Γ\sim 2.2$. These results, together with the EGRET measurement at $E \ge 100$ MeV, constitute a broad-band spectrum containing the peak of the power output at MeV energies, similar to most high-luminosity $γ$-ray blazars. The measured spectral characterstics are then discussed in the framework of the gravitational lens effects.

accepted for ApJ