Hello everyone and welcome back to another blog post! As I mentioned last week, my work right now is really just reading research papers to gather more information and data. This week, I read “The Dark Ages of the Universe and Hydrogen Reionization” by Aravind Natarajan and Naoki Yoshida, as well as “Dark-ages reionization and galaxy-formation simulation – VI. The origins and fate of the highest known redshift galaxy” by Simon J. Mutch et al. Just like last week, I will go over some of the key things I learned and how they relate to my project in a manner that is as simple to understand as I can make it.

The earliest stars

Star formation at the beginning of a galaxy’s lifetime would be very different from how it is today. The gas making up new galaxies would have only recently de-ionized, meaning they would be incredibly hot. The high temperatures in these early galaxies would make it harder for gas to contract into a star, meaning stars would be few and far between. They would also have a much easier time forming in areas with dense gas and high gravity, making many of these early “population III” stars have masses over 100 times that of our sun.

Reionization

These massive stars released huge amounts of high-energy UV light. Matter-antimatter reactions also caused the release of higher energy x-rays and gamma rays. This high energy light would then hit gas particles and ionize them. These ionized gas molecules would be way too hot to condense into stars, contributing even more to the scarcity of population III stars.

The impact on my model

In terms of what all this means for my model, star formation rates will likely end up being much lower than what we see currently in the Milky Way and other nearby galaxies. This would be caused by the presence of ionized gas and the overall high temperatures. Luckily, my model will also be a little easier to make, since I won’t have to consider low-mass stars. This is because there would be too few of them for their small masses to make an impact.

Whether you like it or not, the next few weeks will still be less model-making and more reading. And with that, thanks everyone for tuning in to my blog this week, and I hope to see you next week!