Open AccessOvermerging and mass‐to‐light ratios in phenomenological galaxy formation models
Author(s) -
Van Kampen Eelco,
Jimenez Raul,
Peacock John A.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02955.x
Subject(s) - physics , astrophysics , galaxy formation and evolution , galaxy , star formation , stars , galaxy merger , structure formation , halo , astronomy
We show that the discrepancy between the Tully–Fisher relation and the luminosity function predicted by most phenomenological galaxy formation models is mainly caused by overmerging of galaxy haloes. We circumvent this overmerging problem, which is inherent in both the Press–Schechter formalism and dissipationless N ‐body simulations, by including a specific galaxy halo formation recipe into an otherwise standard N ‐body code. This numerical technique provides the merger trees which, together with simplified gas dynamics and star formation physics, constitute our implementation of a phenomenological galaxy formation model. Resolving the overmerging problem provides us with the means to match both the I ‐band Tully–Fisher relation and the B ‐ and K ‐band luminosity functions within an Ω=1 sCDM structure formation scenario. It also allows us to include models for chemical evolution and starbursts, which improves the match to observational data and renders the modelling more realistic. We show that the inclusion of chemical evolution into the modelling requires a significant fraction of stars to be formed in short bursts triggered by merging events.