Composite star formation histories of early-type galaxies from minor mergers: prospects for WFC3 - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: The star formation history of nearby early-type galaxies is investigated vianumerical modelling. Idealized hydrodynamical N-body simulations with a starformation prescription are used to study the minor merger process between agiant galaxy host and a less massive spiral galaxy satellite withreasonable assumptions for the ages and metallicities of the mergerprogenitors. We find that the evolution of the star formation rate is extendedover several dynamical times and shows peaks which correspond to pericentrepassages of the satellite. The newly formed stars are mainly located in thecentral part of the satellite remnant while the older stars of the initial diskare deposited at larger radii in shell-like structures. After the final plungeof the satellite, star formation in the central part of the remnant cancontinue for several Gyrs depending on the star formation efficiency. Althoughthe mass fraction in new stars is small, we find that the half-mass radiusdiffers from the half-light radius in the V and H bands. Moreover synthetic 2Dimages in J, H, NUV, Hb and V bands, using the characteristic filters of theWide Field Camera 3 WFC3 on the Hubble Space Telescope HST, reveal thatresidual star formation induced by gas-rich minor mergers can be clearlyobserved during and after the final plunge, especially in the NUV band, forinteracting systems at z<0.023 over moderate numbers of orbits ~2 orbitscorrespond to typical exposure times of ~3600 sec. This suggests that WFC3 hasthe potential to resolve these substructures, characterize plausible pastmerger episodes, and give clues to the formation of early-type galaxies.



Autor: S. Peirani IAP, R. M. Crockett, S. Geen, S. Khochfar, S. Kaviraj, J. Silk

Fuente: https://arxiv.org/







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