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arXiv · 1705.09510

A new method for finding and characterizing galaxy groups via low-frequency radio surveys

J. H. Croston·J. Ineson·M. J. Hardcastle·B. Mingo
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Abstract

We describe a new method for identifying and characterizing the thermodynamic state of large samples of evolved galaxy groups at high redshifts using high-resolution, low-frequency radio surveys, such as those that will be carried out with LOFAR and the Square Kilometre Array (SKA). We identify a sub-population of morphologically regular powerful (FRII) radio galaxies and demonstrate that, for this sub-population, the internal pressure of the radio lobes is a reliable tracer of the external intragroup/intracluster medium (ICM) pressure, and that the assumption of a universal pressure profile for relaxed groups enables the total mass and X-ray luminosity to be estimated. Using a sample of well-studied FRII radio galaxies, we demonstrate that our method enables the estimation of group/cluster X-ray luminosities over three orders of magnitude in luminosity to within a factor of ~2 from low-frequency radio properties alone. Our method could provide a powerful new tool for building samples of thousands of evolved galaxy groups at z>1 and characterizing their ICM.

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J. H. Croston, J. Ineson, M. J. Hardcastle, B. Mingo. 2017-05-26. A new method for finding and characterizing galaxy groups via low-frequency radio surveys. https://doi.org/10.1093/mnras/stx1347

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