Glowing emission from carbon monoxide

Composite ALMA and optical image showing glowing emission from carbon monoxide (red) in galaxy PKS0439_008_04. The more distant quasar, PKS0439-433 (central blue feature), revealed through absorption in the visible spectrum the presence of an extended, diffuse halo of molecular gas surrounding the galaxy. The optical data are from the Irénée du Pont Telescope at the Las Campanas Observatory. Credit: Neeleman et al.; ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF); H.-W. Chen, Carnegie Observatories.