N_H-N_HI correlation in gigahertz-peaked-spectrum galaxies

With the Westerbork Synthesis Radio Telescope, we performed HI observations of a sample of known X-ray emitting Gigahertz-peaked-spectrum galaxies with compact-symmetric-object morphology (GPS/CSOs) that lacked an HI absorption detection. We combined radio and X-ray data of the full sample of X-ray emitting GPS/CSOs and found a significant, positive correlation between the column densities of the total and neutral hydrogen (NH and NHI, respectively). Using a Bayesian approach, we simultaneously quantified the parameters of the NH -NHI relation and the intrinsic spread of the data set. For a specific subset of our sample, we found NH ∝ NHI^ b, with b = 0.93(+0.49, -0.33), and σ_int(NH) = 1.27(+1.30,−0.40). The NH-NHI correlation suggests a connection between the physical properties of the radio and X-ray absorbing gas.