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

We report the identification of 2MASX J032441.19+341045.9 (hereafter 2MASXJ0324+3410) with an appealing object which shows the dual properties of both anarrow line Seyfert 1 galaxy (NLS1) and a blazar. Its optical spectrum, whichhas a H\beta line width about 1600 km s^-1 (FWHM), an [OIII] to H\beta lineratio ~0.12, and strong FeII emission, clearly fulfills the conventionaldefinition of NLS1s. On the other hand, 2MASX J0324+3410 also exhibits somebehavior which is characteristic of blazars, including a flat radio spectrumabove 1 GHz, a compact core plus a one-sided jet structure on mas-scale at 8.4GHz, highly variable fluxes in the radio, optical, and X-ray bands, and apossible detection of TeV gamma-ray emission. On its optical image, obtainedwith the HST WFPC2, the active nucleus is displaced from the center of the hostgalaxy, which exhibits an apparent one-armed spiral structure extended to 16kpc. The remarkable hybrid behavior of this object presents a challenge tocurrent models of NLS1 galaxies and $\gamma$-ray blazars.Comment: 12 pages, 2 figures. Accepted to ApJ