  Collective behaviour has been observed in hadronic measurements of high
multiplicity proton+lead collisions at the Large Hadron Collider (LHC), as well
as in (proton, deuteron, helium-3)+gold collisions at the Relativistic
Heavy-Ion Collider (RHIC). To better understand the evolution dynamics and the
properties of the matter created in these small systems, a systematic study of
the soft hadronic observables together with electromagnetic radiation from
these collisions is performed, using a hydrodynamic framework. Quantitative
agreement is found between theoretical calculations and existing experimental
hadronic observables. The validity of the fluid dynamical description is
estimated by calculating Knudsen and inverse Reynolds numbers. Sizeable thermal
yields are predicted for low $p_T$ photons. Further predictions of higher order
charged hadron anisotropic flow coefficients and of thermal photon enhancement
are proposed.
