In a study accepted in “The Astrophysical Journal”, an international team including several LAM researchers report the detection, for the first time, of molecular gas in the Malin 1 galaxy. Malin 1, discovered in the 1980s by David Malin, lies just 366 Mega-Parsec away and is as massive as our galaxy. It is the largest galactic disk (over 200 kiloparsec in diameter). Its late discovery is due to the fact that this extended disk is also very faint, because the galaxy is “diffuse”, with low densities. It had been established that stars form in this giant diffuse disk, but despite several attempts, molecular gas had never been detected. This has now been achieved thanks to Alma, which has made it possible to measure its density in the central part without any doubt (see illustration). Previous attempts had failed because, relative to the size of the galaxy, only a small fraction of it is detected. Alma’s resolution therefore played an important role in this detection. Malin 1 has recently been the subject of renewed interest thanks to instrumental advances that allow us to study diffuse galaxies, such as ALMA for CO, or recently MUSE for ionized gas (Johnson et al. 2024, Junais et al. 2024). The authors received a message from David Malin himself following this publication! The team is now looking forward to successful observations on JWST…
