Examining relationship between Lyman Alpha and the low metal ion spectral features in two gravitationally lensed, high redshift galaxies

The concentrations and kinematics of interstellar and circumgalactic gas play key roles in the evolution of galaxies. Accurately determining the properties of these gaseous regions can be challenging due to the low luminosity of diffuse gas. A standard method to study this medium is spectroscopy of absorption features, using the galaxy itself as a background light source. It has been shown that within populations of galaxies, there exists a strong correlation between the EW of the Lyman Alpha (Ly-a) feature and the EW of the low ion interstellar (LIS) absorption features. Here, we investigate for the first time these correlations between spatially resolved regions of two gravitationally lensed z ~ 2.3 galaxies. Spectroscopic data for these galaxies were obtained using the Keck Cosmic Web Imager (KCWI) instrument. EWs of the Ly-a, Si II 1260, Si II and O I double feature, C II, Si II 1526, Fe II, and Al II were measured for each spaxel within the galaxy. When comparing the EW of the Ly-a feature to the average of the metal features, the spatially resolved relationship in one lensed galaxy shows general agreement with the galaxy-averaged trend, while the second target shows a significantly weaker correlation. We also identify differences in the relations for individual low-ion metal features. These results demonstrate the magnitude of variation in properties of interstellar and circumgalactic media on sub-galactic scales, including the conditions which allow escape of Ly-a emission, and demonstrate the feasibility of kiloparsec-resolution studies at high redshift using lensed galaxies.