Narrow-line Seyfert 1 galaxies (NLS1) are active galactic nuclei (AGN) knownto have small masses of the central black hole and high accretion rates. NLS1sare generally radio-quiet, but a small part of them (about 7\%) are radio-loud.The recent discovery of powerful relativistic jets in radio-loud NLS1s(RLNLS1s), emitting at high-energy $\gamma$-rays, opened intriguing questions.The observed luminosity of the jet is generally weak, smaller than blazars,although when rescaled for the mass of the central black hole, it becomes ofthe same order of magnitude of the latter. The weak luminosity, and henceobserved flux, resulted in a small number of known RLNLS1. From a recent surveyof RLNLS1s, it was found that only 8 out of 42 sources had radio flux densityat 1.4 GHz greater than 100 mJy, while 21 out of 42 had flux density smallerthan 10 mJy. In addition, given the strong variability at all wavelengths, withpresent-day facilities RLNLS1s can often only be detected during high activityperiods. The Square Kilometer Array (SKA), with its superior sensitivity, willbreak this limit, allowing us to unveil a relatively unknown population ofjetted AGN. We present the results of a study aimed at evaluating the scenariothat could emerge after the advent of SKA.
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