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تسجيل مستخدم جديدStormy weather in 3C 196.1: nuclear outbursts and merger events shape the environment of the hybrid radio galaxy 3C 196.1
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تأليف
F. Ricci
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We present a multi-wavelength analysis based on archival radio, optical and X-ray data of the complex radio source 3C 196.1, whose host is the brightest cluster galaxy of a $z=0.198$ cluster. HST data show H$alpha$+[N II] emission aligned with the jet 8.4 GHz radio emission. An H$alpha$+[N II] filament coincides with the brightest X-ray emission, the northern hotspot. Analysis of the X-ray and radio images reveals cavities located at galactic- and cluster- scales. The galactic-scale cavity is almost devoid of 8.4 GHz radio emission and the south-western H$alpha$+[N II] emission is bounded (in projection) by this cavity. The outer cavity is co-spatial with the peak of 147 MHz radio emission, and hence we interpret this depression in X-ray surface brightness as being caused by a buoyantly rising bubble originating from an AGN outburst $sim$280 Myrs ago. A textit{Chandra} snapshot observation allowed us to constrain the physical parameters of the cluster, which has a cool core with a low central temperature $sim$2.8 keV, low central entropy index $sim$13 keV cm$^2$ and a short cooling time of $sim$500 Myr, which is $<0.05$ of the age of the Universe at this redshift. By fitting jumps in the X-ray density we found Mach numbers between 1.4 and 1.6, consistent with a shock origin. We also found compelling evidence of a past merger, indicated by a morphology reminiscent of gas sloshing in the X-ray residual image. Finally, we computed the pressures, enthalpies $E_{cav}$ and jet powers $P_{jet}$ associated with the cavities: $E_{cav}sim7times10^{58}$ erg, $P_{jet}sim1.9times10^{44}$ erg s$^{-1}$ for the inner cavity and $E_{cav}sim3times10^{60}$ erg, $P_{jet}sim3.4times10^{44}$ erg s$^{-1}$ for the outer cavity.
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