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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Rotation curve fitting and its fatal attraction to cores in realistically simulated galaxy observations

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Pineda, Juan C. B. ; Hayward, Christopher C. ; Springel, Volker ; de Oliveira, Claudia Mendes
Total Authors: 4
Document type: Journal article
Source: Monthly Notices of the Royal Astronomical Society; v. 466, n. 1, p. 63-87, APR 2017.
Web of Science Citations: 23

We study the role of systematic effects in observational studies of the cusp-core problem under the minimum disc approximation using a suite of high-resolution (25-pc softening length) hydrodynamical simulations of dwarf galaxies. We mimic realistic kinematic observations and fit the mock rotation curves with two analytic models commonly used to differentiate cores from cusps in the dark matter distribution. We find that the cored pseudo-isothermal sphere (ISO) model is strongly favoured by the reduced chi(2)(v) of the fits in spite of the fact that our simulations contain cuspy Navarro-Frenk-White profiles (NFW). We show that even idealized measurements of the gas circular motions can lead to the incorrect answer if velocity underestimates induced by pressure support, with a typical size of order similar to 5 km s(-1) in the central kiloparsec, are neglected. Increasing the spatial resolution of the mock observations leads to more misleading results because the inner region, where the effect of pressure support is most significant, is better sampled. Fits to observations with a spatial resolution of 100 pc (2 arcsec at 10 Mpc) favour the ISO model in 78-90 per cent of the cases, while at 800-pc resolution, 41-77 per cent of the galaxies indicate the fictitious presence of a dark matter core. The coefficients of our best-fitting models agree well with those reported in observational studies; therefore, we conclude that NFW haloes cannot be ruled out reliably from this type of analysis. (AU)

FAPESP's process: 12/21375-0 - Improving mass models of galaxies using numerical simulations
Grantee:Juan Carlos Basto Pineda
Support type: Scholarships abroad - Research Internship - Doctorate (Direct)
FAPESP's process: 11/51680-6 - Exploring the universe: from the galaxies formation to Earth-like planets with the Giant Magellan Telescope
Grantee:Laerte Sodré Junior
Support type: Special Projects
FAPESP's process: 14/07684-5 - The study of the internal kinematics and of the stellar populations of nearby galaxies
Grantee:Claudia Lucia Mendes de Oliveira
Support type: Regular Research Grants
FAPESP's process: 11/21678-0 - Dark and baryonic matter in spiral galaxies: a joint analysis of observations and numerical simulations
Grantee:Juan Carlos Basto Pineda
Support type: Scholarships in Brazil - Doctorate (Direct)