• quasar
• X-ray emission
• active galactic nuclei
• supermassive black holes progenitors
• structure formation

We studied the visibility of the supermassive black holes’ ancestors in the X-
ray band. Our goal was to assess if their detection is at reach of the current
observational capabilities.
We used the results of a semi-numerical simulation to evaluate the X-ray emis-
sion of the progenitors, taking into account the attenuation processes that occurs
as the radiation travels through the interstellar medium of the host galaxy. Then
we compared our results with the sensitivity of the most powerful observatory
available, the Chandra Space Telescope, finding that the expected emission is
strong enough to be revealed, although these objects are too rare to be detected
with the past surveys.
Accounting for the technical difficulties that arise in performing a survey, we
planned the best observational strategy to maximize the detection probability.
We found that is more advantageous for a survey to explore an area as large as
possible to the detriment of the sensitivity. These results are encouraging because
none of the past surveys implemented the optimal strategy and therefore there
is ample room for improvement: even if they have not been detected so far, we
expect the detection to be possible in the near future.