### Non-linear Chaplygin Gas Cosmologies

Ultra-quick post today, but a new paper on The Arxiv. The title is "Non-linear Chaplygin Gas Cosmologies", catchy eh! But what does it mean?

Essentially, we have two big dark mysteries in the universe, dark matter and dark energy, and what we want to do is try and reduce the number of mysteries by a factor of two. We can do this with a Chaplygin gas, modifying its usual properties so that on small scales it looks like dark matter, while on large scales it acts as dark energy.

In this first paper, we basically lay out our new model, led by Pedro Avelino who was visiting the Sydney Institute for Astronomy from Portugal. It's a bit mathematical, but in coming papers we will detail a number of observational tests we compare the model to.

That is yet to come, and I will write a lot more detail then, but I have to run. Before I go, I'll note that this is my first paper with Krzysztof Bolejko, and so my Erdos Number has significantly shrunk. More on that too!

But for now, well done Pedro!

Essentially, we have two big dark mysteries in the universe, dark matter and dark energy, and what we want to do is try and reduce the number of mysteries by a factor of two. We can do this with a Chaplygin gas, modifying its usual properties so that on small scales it looks like dark matter, while on large scales it acts as dark energy.

In this first paper, we basically lay out our new model, led by Pedro Avelino who was visiting the Sydney Institute for Astronomy from Portugal. It's a bit mathematical, but in coming papers we will detail a number of observational tests we compare the model to.

That is yet to come, and I will write a lot more detail then, but I have to run. Before I go, I'll note that this is my first paper with Krzysztof Bolejko, and so my Erdos Number has significantly shrunk. More on that too!

But for now, well done Pedro!

# Non-linear Chaplygin Gas Cosmologies

(Submitted on 7 Mar 2014)

We study the non-linear regime of Unified Dark Energy models, using Generalized Chaplygin Gas cosmologies as a representative example, and introduce a new parameter characterizing the level of small scale clustering in these scenarios. We show that viable Generalized Chaplygin Gas cosmologies, consistent with the most recent observational constraints, may be constructed for any value of the Generalized Chaplygin Gas parameter by considering models with a sufficiently high level of non-linear clustering.

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