Spreading out and staying sharp - Creating diverse rotation curves via baryonic and self-interaction effects

Peter Creasey, Omid Sameie, Laura V. Sales, Hai Bo Yu, Mark Vogelsberger, Jesús Zavala

Rannsóknarafurð: Framlag til fræðitímaritsGreinritrýni

64 Tilvitnanir (Scopus)


Galactic rotation curves are a fundamental constraint for any cosmological model. We use controlled N-body simulations of galaxies to study the gravitational effect of baryons in a scenario with collisionless cold dark matter (CDM) versus one with a self-interacting dark matter (SIDM) component. In particular, we examine the inner profiles of the rotation curves in the velocity range Vmax = [30-250] km s−1, whose diversity has been found to be greater than predicted by the ΛCDM scenario. We find that the scatter in the observed rotation curves exceeds that predicted by dark matter only mass-concentration relations in either the CDM nor SIDM models. Allowing for realistic baryonic content and spatial distributions, however, helps create a large variety of rotation curve shapes, which is in a better agreement with observations in the case of self-interactions due to the characteristic cored profiles being more accommodating to the slowly rising rotation curves than CDM. We find individual fits to model two of the most remarkable outliers of similar Vmax, UGC 5721 and IC 2574 - the former a cusp-like rotation curve and the latter a seemingly 8-kpc-cored profile. This diversity in SIDM arises as permutations of overly concentrated haloes with compact baryonic distributions versus underdense haloes with extended baryonic discs. The SIDM solution is promising and its feasibility ultimately depends on the sampling of the halo mass-concentration relation and its interplay with the baryonic profiles, emphasizing the need for a better understanding of the frequency of extreme outliers present in current observational samples.

Upprunalegt tungumálEnska
Síður (frá-til)2283-2295
FræðitímaritMonthly Notices of the Royal Astronomical Society
Númer tölublaðs2
ÚtgáfustaðaÚtgefið - 1 jún. 2017


Funding Information:
The authors thank Andrew Pace for sharing his collated data set for the rotation curves, Volker Springel for making AREPO available for this work and James Bullock, Simon White, Oliver Elbert, and Manoj Kaplinghat for useful discussions. This work was supported by the US Department of Energy under Grant no. de-sc0008541 (HBY). HBY acknowledges support from the Hellman Fellows Fund. MV acknowledges support through an MIT RSC award and the support of the Alfred P. Sloan Foundation.

Publisher Copyright:
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society


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