A Narrow-Line Seyfert 1-Blazar Composite Nucleus in 2MASX J0324+3410

We report the identification of 2MASX J032441.19+341045.9 (hereafter 2MASX J0324+3410) with an appealing object that shows the dual properties of both a narrow-line Seyfert 1 galaxy (NLS1) and a blazar. Its optical spectrum, which has a Hb line width of about 1600 km s super(-1) (FWHM), an [O III]-to-Hb line ratio of 0.12, and strong Fe II emission, clearly fulfills the conventional definition of NLS1s. On the other hand, 2MASX J0324+3410 also exhibits some behavior that is characteristic of blazars, including a flat radio spectrum above 1 GHz, a compact core plus a one-sided jet structure on milliarcsecond scale at 8.4 GHz, highly variable fluxes in the radio, optical, and X-ray bands, and a possible detection of TeV g-ray emission. On its optical image, obtained with the HST WFPC2, the active nucleus is displaced from the center of the host galaxy, which exhibits an apparent one-armed spiral structure extended to 16 kpc. The remarkable hybrid behavior of this object presents a challenge to current models of NLS1s and g-ray blazars.