[seminar] Astro Journal Club on 9 December

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held on Wednesday at 3:00 pm (sharp) in the
seminar room F-201 of the Physics Department. This time we will discuss
about the dark energy.

Presenter: Dalibor Perković
Paper title: Can we distinguish early dark energy from a cosmological
constant ?
Authors: Shi, D., and Baugh, C. M.

Summary:
Early dark energy (EDE) models are a class of quintessence dark energy
with a dynamically evolving scalar field which display a small but
non-negligible amount of dark energy at the epoch of matter-radiation
equality. Compared with a cosmological constant, the presence of dark
energy at early times changes the cosmic expansion history and
consequently the shape of the linear theory power spectrum and potentially
other observables. We constrain the cosmological parameters in the EDE
cosmology using recent measurements of the cosmic microwave background and
baryon acoustic oscillations. The best-fitting models favour no EDE; here
we consider extreme examples which are in mild tension with current
observations in order to explore the observational consequences of a
maximally allowed amount of EDE. We study the non-linear evolution of
cosmic structure in EDE cosmologies using large volume N-body simulations.
Many large-scale structure statistics are found to be very similar between
the Lambda cold dark matter (Lambda CDM) and EDE models. We find that the
most promising way to distinguish EDE from Lambda CDM is to measure the
power spectrum on large scales, where differences of up to 15% are
expected.

Link to the paper: http://adsabs.harvard.edu/abs/2015arXiv151100692S

Hope to see you all on Wednesday!

Cheers,
Oskari