Magíster en Ciencias, Mención Astronomía / Cold Dark matter (ΛCDM) models have been remarkably successful to explain the observed large
scale structure of our universe on scales of the order of galaxy clusters (≥ 4 Mpc) and above (therefore
in this work we consider large scale beyond the aforementioned limit). However, this class of models
has some problems at short scales, (∼ 1 Mpc or lower) dubbed Small Scale Controversies . It is
important to remark that, for purposes of our work, we consider lower than 1 Mpc as short-scales.
One of small scale issues is associated to the Dark Matter halo structure: cosmological simulations
that take into account only gravity and collisionless matter, predict halos and substructures with
densities much higher than those derived from galactic dynamics and observations. A possible way
to conciliate theory with observations is to consider self interactive dark matter (SIDM). Models with
SIDM generate predictions consistent with observations on Large Scales, the domain where ΛCDM
is successful, but in addition it does not conflict with observations on "small scale". In absence of
a theory that incorporates self interactive dark matter, it is possible to use the so-called Effective
Field Theory (EFT) framework to investigate some aspects of dark matter. The use of effective
field theory techniques to study the role of dark matter during the period of structure formation in
the Universe has provided a powerful parametrization of the dark matter physics at short scales.
Recently, some researchers have advocated the use of the latter approach to model the large scale
structure as a fluid and considering gravity by incorporating systematically non linear terms in the
theoretical treatment.
In this work, we use some recent approaches [2, 12] to study analytically collisional dark matter in
the form of self interactions. We derive generalized expressions of some of the equations presented
in ref.[2], corresponding to corrections to the momentum equation and the effective energy equation,
and discuss the implications for the behavior of dark matter and its effect on structure formation.
In particular, we find that, by taking into account self interactions, some corrections terms appear
both in the momentum and energy equations. These corrections arise from the non-linear effects
that modify the standard equations. We show that these new terms can solve some of the small
scale issues because the self interactive dark matter reduces the central densities of the galaxy dark
matter halos.
| Identifer | oai:union.ndltd.org:UCHILE/oai:repositorio.uchile.cl:2250/138441 |
| Date | January 2016 |
| Creators | Rincón Rivero, Ángel |
| Contributors | Palma Quilodrán, Gonzalo, Campusano Brown, Luis, Facultad de Ciencias Físicas y Matemáticas, Departamento de Astronomía, Alfaro Solís, Jorge, Escala Astorquiza, Andrés |
| Publisher | Universidad de Chile |
| Source Sets | Universidad de Chile |
| Language | English |
| Detected Language | English |
| Type | Tesis |
| Rights | Atribución-NoComercial-SinDerivadas 3.0 Chile, http://creativecommons.org/licenses/by-nc-nd/3.0/cl/ |
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