PREPRINT
E9F299C4-315C-49FD-B697-488EAF6A1BA3

# Breaking the rules at $z\simeq$0.45: the rebel case of RBS 1055

A. Marinucci, G. Vietri, E. Piconcelli, S. Bianchi, M. Guainazzi, G. Lanzuisi, D. Stern, C. Vignali
arXiv:2209.01575

Submitted on 4 September 2022

## Abstract

We report on a long (250 ks) NuSTAR observation of the bright quasar RBS 1055 performed in March 2021, and archival XMM-Newton pointings (185 ks) taken in July 2014. An optical spectrum of the source taken with the Double Spectrograph at the Palomar Observatory, quasi-simultaneous with the NuSTAR observations, is also analyzed. We find that the two-coronae model, in which a warm and hot corona coexist, well reproduces its broad band spectrum, with temperatures kT${}_{e}={0.12}_{-0.03}^{+0.08}$ keV, kT${}_{e}={30}_{-10}^{+40}$ keV and Thomson optical depths $\tau$=30${}_{-10}^{+15}$ and $\tau$=3.0${}_{-1.4}^{+1.0}$ for the former and the latter component, respectively. We confirm the presence of an intense Fe K$\alpha$ emission line (EW=55$±$6 eV) and, when a toroidal model is considered for reproducing the Compton reflection, a Compton-thin solution with N${}_{\mathrm{H}}=\left({3.2}_{-0.8}^{+0.9}\right)×{10}^{23}$ cm${}^{-2}$ for the circumnuclear reflector is found. The analysis of the optical spectrum reveals a likely peculiar configuration of our line of sight with respect to the nucleus, and the presence of a broad [O III] component, tracing outflows in the NLR, with a velocity shift $v=$1500$±100$ km s${}^{-1}$, leading to a mass outflow rate ${\stackrel{˙}{M}}_{\mathrm{o}\mathrm{u}\mathrm{t}}=25.4±1.5$ M${}_{\odot }$ yr${}^{-1}$ and outflow kinetic power ${\stackrel{˙}{E}}_{\mathrm{k}\mathrm{i}\mathrm{n}}$/L${}_{\mathrm{B}\mathrm{o}\mathrm{l}}$ $\sim$0.33%. We estimate the BH mass to be in the range 2.8$×$10${}^{8}$-1.2$×$10${}^{9}$ M${}_{\odot }$, according to different BLR emission lines, with an average value of <${M}_{\mathrm{B}\mathrm{H}}$>=6.5$×$10${}^{8}$ M${}_{\odot }$. With an Fe K$\alpha$ which is 3$\sigma$ above the value predicted from the EW-L relation and an extreme source brightness at 2 keV (a factor 10-15 higher than the one expected from the optical/UV), RBS 1055 confirms to be an outlier in the X-rays, compared to other objects in the same luminosity and redshift range.

## Preprint

Comment: 11 pages, 10 figures, 4 tables. Accepted for publication in Astronomy & Astrophysics

Subjects: Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Astrophysics of Galaxies