Netherlands Institute for Radio Astronomy (ASTRON) | 2019 Jul 09
For the first time ionised hydrogen has been detected at the lowest frequency ever towards the centre of our Galaxy. The findings originate from a cloud that is both very cold (around -230 degrees Celsius) and also ionised, something that has never been detected before. This discovery may help to explain why stars don’t form as quickly as they theoretically could. ...
The Engineering Development Array ~ Credit: ICRAR
Ionisation is an energetic process that strips electrons away from atoms. The atom will become electrically charged and can then be called an ion. This typically happens in gas that is very hot (10000 degrees Celsius) and where atoms can easily lose their electrons. It was therefore puzzling to discover the ionised hydrogen from very cold gas in this cloud. Normal energy sources, such as photons from massive stars, would not cause this. More exotic energy forms, such as high energy particles created in supernova shockwaves and near black holes, are more likely to be responsible. ...
Spectroscopy with the Engineering Development Array:
Cold H+ at 63 MHz towards the Galactic Centre ~ J.B.R. Oonk et al
- Monthly Notices of the RAS 487(4):4737 (Aug 2019) DOI: 10.1093/mnras/stz950
- arXiv.org > astro-ph > arXiv:1907.03127 > 06 Jul 2019