Universal horizons and Hawking radiation in nonprojectable 2d Horava gravity coupled to a nonrelativistic scalar field

In this paper, we study the nonprojectable 2d Horava gravity coupled with a nonrelativistic scalar field, where the coupling is, in general, nonminimal and of the form f(phi)R, where f(phi) is an arbitrary function of the scalar field phi, and R denotes the 2d Ricci scalar. In particular, we first investigate the Hamiltonian structure and show that there are two first- and two second-class constraints, similar to the pure gravity case, but now the local degrees of freedom is one due to the presence of the scalar field. Then, we present various exact stationary solutions of this coupled system, and find that some of them represent black holes, but now with universal horizons as their boundaries. At these horizons, the Hawking radiation is thermal with temperatures proportional to their surface gravities, which normally depend on the nonlinear dispersion relations of the particles radiated, similar to the (3 + 1)-dimensional case.