The APOSTLE simulations: Rotation curves derived from synthetic 21-cm observations [GA]

The APOSTLE cosmological hydrodynamical simulation suite is a collection of twelve regions $\sim 5$ Mpc in diameter, selected to resemble the Local Group of galaxies in terms of kinematics and environment, and re-simulated at high resolution (minimum gas particle mass of $10^4\,{\rm M}\odot$) using the galaxy formation model and calibration developed for the EAGLE project. I select a sample of dwarf galaxies ($60 < V{\rm max}/{\rm km}\,{\rm s}^{-1} < 120$) from these simulations and construct synthetic spatially- and spectrally-resolved observations of their 21-cm emission. Using the $^{3{\rm D}}$BAROLO tilted-ring modelling tool, I extract rotation curves from the synthetic data cubes. In many cases, non-circular motions present in the gas disc hinder the recovery of a rotation curve which accurately traces the underlying mass distribution; a large central deficit of dark matter, relative to the predictions of cold dark matter N-body simulations, may then be erroneously inferred.

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K. Oman
Fri, 8 Dec 17

Comments: To appear in the proceedings of IAUS 334: Rediscovering our Galaxy, July 10-14 2017, Telegrafenberg, Potsdam, Germany, Eds. C. Chiappini, I. Minchev, E. Starkenburg & M. Valentini