1999A&A...348..678S

Narrow-line Seyfert 1 galaxies are generally found to be radio-quiet and there was only one radio-loud object known so far (PKS 0558-504). Here we present the results of a 50 ksec ASCA observation of the recently discovered second radio-loud NLS1 galaxy RGB J0044+193. The X-ray data are complemented by radio observations and a new optical spectrum for this source. We find evidence for variable radio emission and an inverted radio spectrum of RGB J0044+193. The optical continuum turned out to be extremely blue. This may either indicate additional line emission, for example from FeI, or scattering of a blue intrinsic continuum. The X-ray spectrum shows a clear break around 1.8keV. Above this energy the spectrum is characterized by a power law with a photon index of Γ≃2.1. For energies below 2keV the spectrum is much softer and it can either be modeled with a steeper power law (Γ≃2.7) or a blackbody component with a temperature around 0.2keV. The X-ray count rate of the source decreased by a factor of two within one day and there is evidence for low amplitude variability on much shorter time scales. Given its average 2-10keV X-ray luminosity of (1.35±0.05)x10⁴⁴erg/s, RGB J0044+193 is significantly more variable than a typical broad line Seyfert 1 galaxy of comparable X-ray luminosity, but consistent with the bulk of NLS1 galaxies. The spectral as well as the variability properties of RGB J0044+193 are indistinguishable from those of radio-quiet NLS1s. In particular, we find no evidence for a flat X-ray component due to inverse Compton emission related to the putative non-thermal radio emission from RGB J0044+193. We argue, however, that this does not rule out a pole-on orientation for RGB J0044+193.