The core-cusp problem : a matter of perspective

Show simple item record Genina, Anna Benitez-Llambay, Alejandro Frenk, Carlos S. Cole, Shaun Fattahi, Azadeh Navarro, Julio F. Oman, Kyle A. Sawala, Till Theuns, Tom 2018-03-02T14:15:01Z 2018-03-02T14:15:01Z 2018-02
dc.identifier.citation Genina , A , Benitez-Llambay , A , Frenk , C S , Cole , S , Fattahi , A , Navarro , J F , Oman , K A , Sawala , T & Theuns , T 2018 , ' The core-cusp problem : a matter of perspective ' , Monthly Notices of the Royal Astronomical Society , vol. 474 , no. 1 , pp. 1398-1411 .
dc.identifier.other PURE: 99734518
dc.identifier.other PURE UUID: d47a3063-6576-4e1f-beab-e5f0d240c6ad
dc.identifier.other WOS: 000424339500098
dc.identifier.other Scopus: 85045910329
dc.description.abstract The existence of two kinematically and chemically distinct stellar subpopulations in the Sculptor and Fornax dwarf galaxies offers the opportunity to constrain the density profile of their matter haloes by measuring the mass contained within the well-separated half-light radii of the two metallicity subpopulations. Walker and Penarrubia have used this approach to argue that data for these galaxies are consistent with constant-density 'cores' in their inner regions and rule out 'cuspy' Navarro-Frenk-White (NFW) profiles with high statistical significance, particularly in the case of Sculptor. We test the validity of these claims using dwarf galaxies in the APOSTLE (A Project Of Simulating The Local Environment) Lambda cold dark matter cosmological hydrodynamic simulations of analogues of the Local Group. These galaxies all have NFW dark matter density profiles and a subset of them develop two distinct metallicity subpopulations reminiscent of Sculptor and Fornax. We apply a method analogous to that of Walker and Penarrubia to a sample of 50 simulated dwarfs and find that this procedure often leads to a statistically significant detection of a core in the profile when in reality there is a cusp. Although multiple factors contribute to these failures, the main cause is a violation of the assumption of spherical symmetry upon which the mass estimators are based. The stellar populations of the simulated dwarfs tend to be significantly elongated and, in several cases, the two metallicity populations have different asphericity and are misaligned. As a result, a wide range of slopes of the density profile are inferred depending on the angle from which the galaxy is viewed. en
dc.format.extent 14
dc.language.iso eng
dc.relation.ispartof Monthly Notices of the Royal Astronomical Society
dc.rights unspecified
dc.rights.uri info:eu-repo/semantics/openAccess
dc.subject galaxies: dwarf
dc.subject galaxies: formation
dc.subject galaxies: kinematics and dynamics
dc.subject dark matter
dc.subject HALOES
dc.subject FEEDBACK
dc.subject EVOLUTION
dc.subject UNIVERSE
dc.subject 115 Astronomy, Space science
dc.title The core-cusp problem : a matter of perspective en
dc.type Article
dc.contributor.organization Department of Physics
dc.description.reviewstatus Peer reviewed
dc.relation.issn 0035-8711
dc.rights.accesslevel openAccess
dc.type.version publishedVersion

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