Radio and X-ray Observations of the Restarted Radio Galaxy in the Galaxy Cluster CL 0838+1948

Galaxies

Simona Giacintucci¹  Emil Polisensky¹  Wendy Peters¹  Namir E. Kassim¹  Tracy Clarke¹ 

[1] Naval Research Laboratory, 4555 Overlook Avenue SW, Code 7213, Washington, DC 20375, USA;

关键词: radio galaxies;    active galactic nuclei;    galaxy clusters;   

DOI  :  10.3390/galaxies9040108

来源: DOAJ

【 摘 要 】

We present VLA Low-band Ionosphere and Transient Experiment (VLITE) 338 MHz observations of the galaxy cluster CL 0838+1948. We combine the VLITE data with Giant Metrewave Radio Telescope 610 MHz observations and survey data. The central galaxy hosts a 250 kpc source whose emission is dominated by two large lobes at low frequencies. At higher frequencies, a pair of smaller lobes (∼30 kpc) is detected within the galaxy optical envelope. The observed morphology is consistent with a restarted radio galaxy. The outer lobes have a spectral index ${\alpha }_{\mathrm{out}}=1.6$, indicating that they are old, whereas the inner lobes have ${\alpha }_{\mathrm{inn}}=0.6$, typical for an active source. Spectral modeling confirms that the outer emission is a dying source whose nuclear activity switched off not more than 110 Myr ago. Using archival Chandra X-ray data, we compare the radio and hot gas emission. We find that the active radio source is contained within the innermost and X-ray brightest region, possibly a galactic corona. Alternatively, it could be the remnant of a larger cool core whose outer layers have been heated by the former epoch of activity that has generated the outer lobes.

【 授权许可】

Unknown