H_3^+ absorption and emission in local U/LIRGs with JWST/NIRSpec: Evidence for high H_2 ionization rates

We study the 3.4-4.4\mum fundamental rovibrational band of H3+, a key tracer of the ionization of the molecular interstellar medium (ISM), in a sample of 12 local (d< 400 Mpc) ultra/luminous infrared galaxies (U/LIRGs) observed with JWST/NIRSpec. The P, Q, and R branches of the band are detected in 13... Show more