Stormy Weather in 3C 196.1: Nuclear Outbursts and Merger Events Shape the Environment of the Hybrid Radio Galaxy 3C 196.1
Abstract
We present a multiwavelength 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 Hα+[N II] emission aligned with the jet 8.4 GHz radio emission. An Hα+[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 southwestern Hα+[N II] emission is bounded (in projection) by this cavity. The outer cavity is cospatial 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 active galactic nuclei outburst ∼280 Myr ago. A Chandra snapshot observation allowed us to constrain the physical parameters of the cluster, which has a cool core with a low central temperature ∼2.8 keV, low central entropy index ∼13 keV cm2 and a short cooling time of ∼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 ∼ 7 × 1058 erg, P jet ∼ 1.9 × 1044 erg s-1 for the inner cavity and E cav ∼ 3 × 1060 erg, P jet ∼ 3.4 × 1044 erg s-1 for the outer cavity.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2018
- DOI:
- 10.3847/1538-4357/aae487
- arXiv:
- arXiv:1809.10693
- Bibcode:
- 2018ApJ...867...35R
- Keywords:
-
- galaxies: active;
- galaxies: clusters: general;
- galaxies: clusters: intracluster medium;
- radio continuum: galaxies;
- radio continuum: ISM;
- X-rays: galaxies: clusters;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 14 pages, 4 figures, ApJ accepted