2013MNRAS.433..952D

We report on multifrequency observations of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS 1502+036 performed from radio to γ-rays during 2008 August-2012 November by Fermi-Large Area Telescope (LAT), Swift (X-ray Telescope and Ultraviolet/Optical Telescope), Owens Valley Radio Observatory, Very Long Baseline Array (VLBA) and Very Large Array. No significant variability has been observed in γ-rays, with 0.1-100GeV flux that ranged between (3-7)x10-8 ph cm-2 s-1 using 3-month time bins. The photon index of the LAT spectrum (Γ = 2.60±0.06) and the apparent isotropic γ-ray luminosity (L0.1-100GeV = 7.8x1045 erg s-1) over 51 months are typical of a flat spectrum radio quasar. The radio spectral variability and the one-sided structure, in addition to the observed γ-ray luminosity, suggest a relativistic jet with a high Doppler factor. In contrast to SBS 0846+513, the VLBA at 15 GHz did not observe superluminal motion for PKS 1502+036. Despite having the optical characteristics typical of a narrow-line Seyfert 1 galaxy, radio and γ-ray properties of PKS 1502+036 are found to be similar to those of a blazar at the low end of the black hole mass distribution for blazars. This is in agreement with what has been found in the case of the other γ-ray emitting narrow-line Seyfert 1 SBS 0846+513.