X-ray Absorption and Reprocessing in the $z \sim 2.5$ Lensed Quasar 2MASS J1042+1641

TL;DR

This study presents broadband X-ray observations of a high-redshift lensed quasar, revealing complex absorption and reprocessing features, and explores models of the reprocessing material, with implications for identifying such quasars.

Contribution

It provides the first broadband X-ray spectrum of a $z \\sim 2.5$ lensed quasar and compares reprocessing models, enhancing understanding of AGN structure and aiding in candidate identification.

Findings

Detected strong Compton-thin X-ray absorption ($N_H \\sim 3-4 \\times 10^{23}$ cm$^{-2}$)

Reprocessing can occur in either a torus or accretion disk model, both fitting the data

Supports using combined X-ray and IR surveys to identify lensed quasars

Abstract

We present new broadband X-ray observations of the $z \sim 2.5$ lensed quasar 2MASS J1042+1641, combining $XMM$-$Newton$, $Chandra$ and $NuSTAR$ to provide coverage of the X-ray spectrum over the 0.3$-$40 keV bandpass in the observed frame, corresponding to the $\sim$1$-$140 keV band in the rest-frame of 2MASS J1042+1641. The X-ray data show clear evidence for strong (but still Compton-thin) X-ray absorption, $N_{\rm{H}} \sim 3-4 \times 10^{23}$ cm$^{-2}$, in addition to significant reprocessing by Compton-thick material that must lie away from our line-of-sight to the central X-ray source. We test two different interpretations for the latter: first that the reprocessing occurs in a classic AGN torus, as invoked in unification models, and second that the reprocessing occurs in the accretion disc. Both models can successfully reproduce the observed spectra, and both imply that the source is viewed at moderately low inclinations ($i < 50^{\circ}$) despite the heavy line-of-sight absorption. Combining the X-ray data with infrared data from $WISE$, the results seen from 2MASS J1042+1641 further support the recent suggestion that large X-ray and IR surveys may together be able to identify good lensed quasar candidates in advance of detailed imaging studies.