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arXiv · 1402.7174

VLBA Observations of Mrk 6: Probing the Jet-Lobe Connection

P. Kharb·C. P. O'Dea·S. A. Baum·M. J. Hardcastle·D. Dicken·J. H. Croston·B. Mingo·J. Noel-Storr
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Abstract

We present the results of high resolution VLBI observations at 1.6 and 4.9 GHz of the radio-loud Seyfert galaxy, Mrk 6. These observations are able to detect a compact radio core in this galaxy for the first time. The core has an inverted spectral index ($α^{1.6}_{4.9}$=+1.0$\pm$0.2) and a brightness temperature of $1\times10^8$ K. Three distinct radio components which resemble jet elements and/or hot spots, are also detected. The position angles of these elongated jet elements point, not only to a curved jet in Mrk 6, but also towards a connection between the AGN and the kpc-scale radio lobes/bubbles in this galaxy. Firmer constraints on the star formation rate provided by new Herschel observations (SFR $<0.8$ M$_\sun$ yr$^{-1}$) make the starburst-wind powered bubble scenario implausible. From plasma speeds obtained via prior Chandra X-ray observations, and ram pressure balance arguments for the ISM and radio bubbles, the north-south bubbles are expected to take $7.5\times10^6$ yr to form, and the east-west bubbles $1.4\times10^6$ yr. We suggest that the jet axis has changed at least once in Mrk 6 within the last $\approx10^7$ yr. A comparison of the nuclear radio-loudness of Mrk 6 and a small sample of Seyfert galaxies with a subset of low-luminosity FRI radio galaxies reveals a continuum in radio properties.

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P. Kharb, C. P. O'Dea, S. A. Baum, M. J. Hardcastle, D. Dicken, J. H. Croston, B. Mingo, J. Noel-Storr. 2014-03-10. VLBA Observations of Mrk 6: Probing the Jet-Lobe Connection. https://doi.org/10.1093/mnras%2Fstu421

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