The host galaxy of the γ-ray-emitting narrow-line Seyfert 1 galaxy PKS 1502+036

The detection of gamma-ray emission from narrow-line Seyfert 1 galaxies (NLSy1) has challenged the idea that large black hole (BH) masses (>= 10(8) M-circle dot) are needed to launch relativistic jets. We present near-infrared imaging data of the gamma-ray-emitting NLSy1 PKS 1502+036 obtained with the Very Large Telescope. Its surface brightness profile, extending to similar to 20 kpc, is well described by the combination of a nuclear component and a bulge with a Sersic index n = 3.5, which is indicative of an elliptical galaxy. A circumnuclear structure observed near PKS 1502+036 may be the result of galaxy interactions. A BH mass of similar to 7 x 10(8) M-circle dot has been estimated by the bulge luminosity. The presence of an additional faint disc component cannot be ruled out with the present data, but this would reduce the BH mass estimate by only similar to 30 per cent. These results, together with analogous findings obtained for FBQS J1644+2619, indicate that the relativistic jets in gamma-ray-emitting NLSy1 are likely produced by massive black holes at the centre of elliptical galaxies.