2024ApJ...971...63W

We present Keck Cosmic Web Imager integral field observations of extended Lyα emission in the circumgalactic medium of 27 typical star-forming galaxies at z ∼ 2, drawn from the Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) Deep Evolution Field (MOSDEF) survey. Using composite spectra in two bins of star formation rate (SFR), star formation rate surface density (Σ_SFR), and other galactic properties, we measure spatial variations in the Lyα profile across three regions in the Lyα halo. We find single-peaked, redshifted profiles are ubiquitous within a central 7 kpc radius region. Further out in the halo (7-14 and 14-21 kpc), the Lyα profile of the resonantly scattered emission exhibits more diversity, either transitioning to a double-peaked profile or remaining single peaked across the halo. We find a shorter scale length of the Lyα halo surface brightness profile for composite halos with faster winds. The composites have a similar average inclination, suggesting those with faster winds clear channels in the interstellar medium (ISM), reducing the fraction of Lyα photons resonantly scattered to large radii. A uniform expanding shell radiative transfer model reproduces the shape but not the normalization of the observed double-peaked Lyα profiles. Models that adopt a more realistic, clumpy ISM are likely needed to reproduce both the shape and normalization of the Lyα profiles.