$v_{n}$ measurement in Au+Au collisions at $\sqrt{s_{NN}} =$ 27 GeV with the Event Plane Detector from STAR

The measurement of pseudorapidity ($\eta$) dependence of $v_{n}$ at lower collision energies can provide unique constraints on the three-dimensional initial conditions, baryon transport, shear viscosity over entropy density as well as its dependence on temperature and baryon chemical potential. The combination of the Event Plane Detector (EPD, $2.1<|\eta|<5.1$) installed in the year 2018, STAR time projection chamber (TPC, $|\eta|<1$) and high statistics Beam Energy Scan phase-II data enables us to perform precise measurements of $v_{n}(\eta)$. In this presentation, we will show the directed flow ($v_{1}(\eta)$) and elliptic flow ($v_{2}(\eta)$) of charged hadrons measured over ten units of pseudorapidity using $\sqrt{s_{NN}} =$ 27 GeV Au+Au data taken in 2018 and the comparisons to hydrodynamic model predictions. We observed a sign change of $v_{1}(\eta)$ at $\eta=Y_{beam}$ and longitudinal scaling of $v_1$ with $|\eta|-Y_{beam}$ when compared with earlier measurements from the PHOBOS collaboration. We will also present the transverse momentum ($p_{T}$) dependence of $v_{1}$ at midrapidity.