Constraining Equation of State of Dark Matter: Including Weak Gravitational Lensing

Usually the equation of state (EoS) of dark matter is zero when it is cold, however there exists the possibility of a (effective) nonzero EoS of dark matter due to its decay and interaction with dark energy. In this work, we try to constrain the EoS of dark matter w(dm) using the currently available cosmic observations which include the geometrical and dynamical measurements. For the geometrical measurements, the luminosity distance of type Ia supernovae, the angular diameter distance and comoving sound horizon from baryon acoustic oscillations and the cosmic microwave background radiation will be employed. The data points from the redshift-space distortion and weak gravitational lensing will be taken as dynamical measurements. Using the Markov chain Monte Carlo method, we obtain a very tight constraint on the EoS of dark matter: w(dm) = 0.0000532(-0.000686-0.00136-0.00177)(+0.000692+0.00136+0.00183)