These results are consistent with earlier works like @2000ApJ...528..597T [@2006ApJ...648...47C; @2006ApJ...648L...1C; @2008ApJ...684...18C; @thomas08; @Alvarez10; @2014MNRAS.445.3674Y]. The lengths of different regions depend on the source properties. The strength, as well as the volume of the absorption signal, is much larger than the emission signal for the sources we consider. For example, the minimum ${\delta T_{\rm b}}$ for the fiducial mini-QSO model is $\sim -160 $ mK, which is much larger compared to the maximum ${\delta T_{\rm b}}$ $\sim$ 30 mK. Thus, one can expect that this region will be the easiest to be detected in radio images, while it may be difficult to identify the [H [ii ]{}]{} and emission regions because of the contamination of the weak signal by the system noise and foregrounds. One can also notice that the strength of the absorption signal is larger in the case of the models Galaxy and HMXB compared to the mini-QSO. In other words, one may expect higher detectability for the Galaxy and HMXB source models than the mini-QSO, assuming the sources to be isolated. This will be discussed in more detail in the later part of the paper.

The one-dimensional ${\delta T_{\rm b}}$ profile around the fiducial mini-QSO source model 