Through this research we seek to determine the incidence of primordial black holes in the formation of dark matter and whether it is feasible for stars to form.
Sergio Molleda, CATA.- The young astronomer Catalina Casanueva, a member of the Center for Astrophysics and Related Technologies (CATA), published an interesting study on primordial black holes and their connection with dark matter in the prominent journal EDP Sciences.
She is a doctoral candidate in astrophysics and is part of the team of Patricia Tissera, Principal Investigator of the Cosmology and Galaxy Formation area at CATA.
This study allows us to explore primordial black holes, whose existence is not yet confirmed, and their possible influence on the evolution of the universe. These objects are theoretical candidates for dark matter, and their study deepens our understanding of both it and cosmic formation and evolution.
These can only form a very small fraction of dark matter. If they were a significant part, they would drastically alter the formation of stars and galaxies.
“Primordial black holes are not formed by the death of a star, but rather originate in the early universe, due to the extremely dense and energetic conditions of that time. During the early moments after the Big Bang, density fluctuations in the universe were so intense that some regions were able to collapse under their own gravity, forming these black holes. They are relevant because they are candidates for dark matter, which constitutes approximately 85% of the matter in the universe and determining the nature of dark matter is one of the greatest mysteries of current astrophysics,” explains Catalina Casanueva.
Their paper establishes that they managed to place a restriction on the amount of dark matter that could be composed of primordial black holes of a specific mass and created a model to simulate how their presence would affect the gas of the galaxy. Through this, determine whether it is feasible for stars to form or not, depending on the model used.
They assumed that very massive holes could generate a lot of energy, heat too much gas and inhibit star formation. Now, when considering very small holes, 10^{-12} solar masses, the idea was that it would not affect that much, which actually ended up turning out to be the case, but at an intermediate level there was no further precedent.
As the candidate they studied was a black hole of 33 solar masses, which coincides with an observation of a Merger of black holes observable through gravitational waves, they wanted to see if it was feasible for galaxies to exist and thus establish the limits.
“There are astronomers who impose limits on the existence of primordial black holes through observations, such as through the gravitational lensing effect. However, we focus on studying the beginnings of the universe using simulations. These allow us to recreate the extreme conditions of the early universe and study how primordial black holes might have affected gas and galaxy formation at those stages. This type of analysis cannot be performed with observational methods due to the enormous distances and times involved. “Through simulations, we can explore theoretical scenarios and better understand the potential influence of primordial black holes on the evolution of the universe, providing a more complete view of their impact on the formation and development of cosmic structures,” adds Catalina Casanueva, al break down the study published in EDP Sciences.
In conclusion, when developing this model, they carried out tests and determined for different masses of black holes what would be the maximum fraction of dark matter that they could compose. Those of 1 solar mass cannot constitute more than 1% of the dark matter. Those of 33 and 100 solar masses cannot constitute more than 0.1%
