  Context. The diffuse X-ray emission surrounding radio galaxies is generally
interpreted either as due to inverse Compton scattering of non-thermal
radio-emitting electrons on the Cosmic Microwave Background (IC/CMB), or as the
thermal emission arising from the hot gas of the intergalactic medium (IGM)
permeating galaxy clusters hosting such galaxies, or as a combination of both.
In this work we present an imaging and spectral analysis of Chandra
observations for the radio galaxy 3C 187 to investigate its diffuse X-ray
emission and constrain the contribution of these different physical mechanisms.
Aims. The main goals of this work are: (i) to evaluate the extension of the
diffuse X-ray emission from this source, (ii) to investigate the two main
processes that can account for its origin - IC/CMB and thermal emission from
the IGM - and (iii) to test the possibility for 3C 187 to belong to a cluster
of galaxies, that can account for the observed diffuse X-ray emission. Methods.
To evaluate the extension of the X-ray emission around 3C 187 we extracted
surface flux profiles along and across the radio axis. We also extracted X-ray
spectra in the region of the radio lobes and in the cross-cone region to
estimate the contribution of the non-thermal (IC/CMB) and thermal (IGM)
processes to the observed emission, making use of radio (VLA and GMRT) data to
investigate the multi-wavelength emission arising from the lobes. We collected
Pan-STARRS photometric data to investigate the presence of a galaxy cluster
hosting 3C 187, looking for the presence of a "red sequence" in the source
field in the form of a tight clustering of the galaxies in the color space...
