Colliding clusters and dark matter self-interactions

By Felix Kahlhoefer, K. Schmidt-Hoberg, M. Frandsen, S. Sarkar. 2013

183 citations recorded by the source corpus.

When a dark matter halo moves through a background of dark matter particles, self-interactions can lead to both deceleration and evaporation of the halo and thus shift its centroid relative to the collisionless stars and galaxies. We study the magnitude and time evolution of this shift for two classes of dark matter self-interactions, viz. frequent self-interactions with small momentum transfer (e.g. due to long-range interactions) and rare self-interactions with large momentum transfer (e.g. contact interactions), and find important differences between the two cases. We find that neither effect can be strong enough to completely separate the dark matter halo from the galaxies, if we impose conservative bounds on the self-interaction cross-section. The majority of both populations remain bound to the same gravitational potential and the peaks of their distributions are therefore always coincident. Consequently any apparent separation is mainly due to particles which are leaving the gravitational potential, so will be largest shortly after the collision but not observable in evolved systems. Nevertheless the fraction of collisions with large momentum transfer is an important characteristic of self-interactions, which can potentially be extracted from observational data and provide an important clue as to the nature of dark matter.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/ef162987bd6d234fdc8d0f7cb7a995f8994297dd

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Citations in the corpus

Production regimes for Self-Interacting Dark Matter (2015, background): “DM self-interactions induced by a heavy mediator, denoted as σAA, or by a light mediator, denoted as σT , would lead to slightly different effects in observations [64].”
ETHOS - an effective theory of structure formation: dark matter physics as a possible explanation of the small-scale CDM problems (2015, unknown): “This model is characterised by an interaction between DM and 1 Note that in some cases one needs to go beyond the transfer cross section to describe the effect of self-interactions, see e.g. Kahlhoefer et al. (2014).”
Dark matter direct-detection experiments (2015, background): “An upper limit to the self-interaction crosssection for dark matter can be derived from these observations [23].”
A taste of dark matter: flavour constraints on pseudoscalar mediators (2014, unknown): “For velocity-independent self-interactions, however, there are important constraints from colliding galaxy clusters [44, 45], sub-halo evaporation [46, 47] and elliptical galaxies [48–50].”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “If the interactions are rare but exchange little momentum (often corresponding to long-ranged forces),the dark matter will be decelerated by an additional drag force and become spatially offset [647].”
Gravitational probes of dark matter physics (2017, background): “However, recent works shows that the separation between dark matter and galaxies is expected to be small in SIDM during the merger, in some cases much smaller than the observed separations, even for large (σ/m ∼ 10 cm(2)/g) cross sections [227, 228, 232, 230, 231].”
What does the Bullet Cluster tell us about Self-Interacting Dark Matter? (2016, methodology): “…the galaxies and DM associated with the smaller DM halo (the ‘bullet’) as well as limits on the loss of DM mass from the bullet have been used to place constraints on the DM–DM elastic scattering cross-section (Randall et al. 2008; Kahlhoefer et al. 2014, hereafter R08 and K14, respectively).”
The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827 (2015, methodology): “Instead, Williams & Saha (2011) interpreted the offset in terms of dark matter’s self-interaction crosssection σ DM/m, using a toy model of interactions equivalent to an optical depth (see their equation 33 and see also Massey et al. 2011; Harvey et al. 2014; Kahlhoefer et al. 2014).”
Self-Interacting Dark Matter from a Non-Abelian Hidden Sector (2014, background): “These mixed scenarios are strongly interacting analogues of atomic dark matter [103–107] and inspire further simulation of the galactic dynamics in cases where there are two components of dark matter with naturally very different mass scales and different selfinteraction rates.”