%AFurniss, A.%AWorseck, G.%AFumagalli, M.%AJohnson, C.%AWilliams, D.%APontrelli, P.%AProchaska, J.%BJournal Name: The Astronomical Journal; Journal Volume: 157; Journal Issue: 2 %D2019%I %JJournal Name: The Astronomical Journal; Journal Volume: 157; Journal Issue: 2 %K %MOSTI ID: 10107528 %PMedium: X %TSpectroscopic Redshift of the Gamma-Ray Blazar B2 1215+30 from Ly α Emission %X %0Journal Article