IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Non-parametric Morphologies of Mergers in the Illustris Simulation
Autor/es:
EMANUEL SILLERO; LUCAS BIGNONE; DIEGO GARCÍA LAMBAS; SUSANA PEDROSA; PATRICIA TISSERA; LEONARDO PELLIZZA
Lugar:
Santiago de Chile
Reunión:
Workshop; Second Chilean Workshop on Theoretical and Numerical Astrophysics; 2016
Institución organizadora:
Universidad Católica
Resumen:
We study non-parametric morphologies of mergers events in the context of afull cosmological simulation, the Illustris project. We produce mock g-bandimages comparable to observational surveys from the publicly availableIllustris simulation idealized mock images at $z=0$. We then measure nonparametric indicators: asymmetry, Gini, $M_{20}$, clumpiness and concentrationfor a set of galaxies with $M_* >10^{10}$ M$_odot$. We correlate theseautomatic statistics with the recent merger history of galaxies and with thepresence of close companions. Our main contribution is to assess in a fullcosmological context, the empirically derived non-parametric demarcation lineand average time-scales used to determine the merger rate observationally. Wefound that 98 per cent of galaxies above the demarcation line have a closecompanion or have experienced a recent merger event. The merginessanticorrelates clearly with the elapsing time to the last merger event.  Wealso find that the asymmetry correlates with galaxy pair separation andrelative velocity, exhibiting the larger enhancements for those systems withpair separations  $d < 50$  h$^{-1}$ kpc and relative velocities $V < 350$ kms$^{-1}$. We find that the $G-M_{20}$ is most sensitive to recent mergers($sim0.14$ Gyr) and to ongoing mergers with stellar mass ratios greater than0.1. For this indicator, we compute a merger average observability protect{time-scale} of $sim0.2$ Gyr and demonstrate that the morphologically derivedmerger rate recovers the intrinsic total merger rate of the simulation and themerger rate as a function of stellar mass.