Which type of emission closely traces the star-forming regions of a galaxy?
none of these
coronal X-ray emission
21 cm emission
molecular CO emission
Why don't you know? The answer is in the lectures
I have used these answers once in a cosmology quiz and it resulted in a wrong embarrassment.
21 cm emission
The type of emission that closely traces the star-forming regions of a galaxy is the molecular CO (carbon monoxide) emission.
To determine this, we need to understand the properties of each emission type and how they relate to star formation:
1. Coronal X-ray emission: This type of emission is associated with high-temperature gas in the outer atmosphere of stars, typically seen around active galactic nuclei or highly energetic processes. While X-ray emission can provide valuable information about the properties of galaxies, it is not directly related to star formation.
2. 21 cm emission: This emission refers to the radio waves with a wavelength of 21 centimeters, which are characteristic of neutral hydrogen gas (H I). While neutral hydrogen gas is present in interstellar space, it is not exclusively associated with star-forming regions.
3. Molecular CO emission: Carbon monoxide (CO) is a molecule that is abundant in molecular clouds, which are the birthplaces of stars. As stars form, they accrete material from these molecular clouds, and the presence of CO emission can indicate the existence of these star-forming regions.
Based on this information, we can conclude that the molecular CO emission most closely traces the star-forming regions of a galaxy. Detecting and mapping CO emission in galaxies is a common method used to study the processes and properties of star formation.