The CH radical at radio wavelengths: revisiting emission in the 3.3 GHz ground-state lines Arshia M. Jacob, Karl M. Menten, Helmut Wiesemeyer and Gisela N. Ortiz-León A&A, 650 (2021) A133 Published online: 17 June 2021 DOI: 10.1051/0004-6361/202140419