ionized hydrogen can be found in star formation in astronomy.
ionized hydrogen can be found in star formation in astronomy.
where can ionized hydrogen be found in astronomy?
star formation
ngc 4631 contains a central starburst, which is a region of intense star formation. the strong star formation is evident in the emission from ionized hydrogen and interstellar dust heated by the stars formed in the starburst. the most massive stars that form in star formation regions only burn hydrogen gas through fusion for a short period of time, after which they explode as supernovae. so many supernovae have exploded in the center of ngc 4631 that they are blowing gas out of the plane of the galaxy. this superwind can be seen in x-rays and in spectral line emission. the gas from this superwind has produced a giant, diffuse corona of hot, x-ray emitting gas around the whole galaxy.
ngc 4631
reionization is evidenced from observations of quasars. quasars are a form of active galaxy, and the most luminous objects observed in the universe. electrons in neutral hydrogen have a specific patterns of absorbing photons, related to electron energy levels and called the lyman series. ionized hydrogen does not have electron energy levels of this kind. therefore, light travelling through ionized hydrogen and neutral hydrogen shows different absorption lines. in addition, the light will have travelled for billions of years to reach us, so any absorption by neutral hydrogen will have been redshifted by varied amounts, rather than by one specific amount, indicating when it happened. these features make it possible to study the state of ionization at many different times in the past. they show that reionization began as "bubbles" of ionized hydrogen which became larger over time. they also show that the absorption was due to the general state of the universe (the intergalactic medium) and not due to passing through galaxies or other dense areas. reionization might have started to happen as early as "z"=16 (250 million years of cosmic time) and was complete by around "z"=9 or 10 (500 million years)before gradually diminishing and probably coming to an end by around "z"=5 or 6 (1 billion years) as the era of population iii stars and quasars – and their intense radiation – came to an end, and the ionized hydrogen gradually reverted to neutral atoms.
chronology of the universe