Early-type galaxies (ETGs) are observed to be more compact, on average, at z > 2 than at z=0, at fixed stellar mass. Recent observational works suggest that such size evolution could reflect the similar evolution of the host dark matter halo density as a function of the time of galaxy quenching. We explore this hypothesis by studying the distribution of halo central velocity dispersion (sigmazero) and half-mass radius (rh) as functions of halo mass M and redshift z, in a cosmological LambdaCDM N-body simulation. In the range 0<z<2.5, we find sigmazero~M^{0.31-0.37} and rh~M^{0.28-0.32}, close to the values expected for homologous virialized systems. At fixed M in the range 10^11Msun <M< 5.5x10^14Msun we find sigmazero~(1+z)^0.35 and rh~(1+z)^{-0.7}. We show that such evolution of the halo scaling laws is driven by individual haloes growing in mass following the evolutionary tracks sigmazero~M^0.2 and rh~M^0.6, consistent with simple dissipationless merging models in which the encounter orbital energy is accounted for. We compare the N-body data with ETGs observed at 0<z<3 by populating the haloes with a stellar component under simple but justified assumptions: the resulting galaxies evolve consistently with the observed ETGs up to z=2, but the model has difficulty reproducing the fast evolution observed at z>2. We conclude that a substantial fraction of the size evolution of ETGs can be ascribed to a systematic dependence on redshift of the dark matter haloes structural properties.

Posti L., Nipoti C., Stiavelli M., Ciotti L. (2014). The imprint of dark matter haloes on the size and velocity dispersion evolution of early-type galaxies. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 440, 610-623 [10.1093/mnras/stu301].

The imprint of dark matter haloes on the size and velocity dispersion evolution of early-type galaxies

POSTI, LORENZO;NIPOTI, CARLO;CIOTTI, LUCA
2014

Abstract

Early-type galaxies (ETGs) are observed to be more compact, on average, at z > 2 than at z=0, at fixed stellar mass. Recent observational works suggest that such size evolution could reflect the similar evolution of the host dark matter halo density as a function of the time of galaxy quenching. We explore this hypothesis by studying the distribution of halo central velocity dispersion (sigmazero) and half-mass radius (rh) as functions of halo mass M and redshift z, in a cosmological LambdaCDM N-body simulation. In the range 02. We conclude that a substantial fraction of the size evolution of ETGs can be ascribed to a systematic dependence on redshift of the dark matter haloes structural properties.
2014
Posti L., Nipoti C., Stiavelli M., Ciotti L. (2014). The imprint of dark matter haloes on the size and velocity dispersion evolution of early-type galaxies. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 440, 610-623 [10.1093/mnras/stu301].
Posti L.; Nipoti C.; Stiavelli M.; Ciotti L.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/238481
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