1705.00013
Observational evidence of galaxy assembly bias
Montero-Dorta, et al
Analyze the spectra of 300,000 LRGs with stellar masses M*>1e11 Msun from SDSS-III BOSS survey. By studying their SFHs, find 2 main evolutionary paths converging into the same quiescent galaxy population at z~0.55. Fast-growing LRGs assemble 80% of their stellar mass very early on (z~5), whereas slow-growing LRGs reach the same evolutionary state at z~1.5. Further investigation reveals that their clustering properties on scales of ~1-30 Mpc are, at a high level of significance, also different. Fast-growing LRGs are found to be more strongly clustered and reside in overall denser LSS environments than slow-growing systems, for a given stellar-mass threshold. Results imply a dependence of clustering on stellar-mass assembly history (naturally connected to the mass-formation history of the corresponding halos) for a homogeneous population of similar mass and color, which constitutes a strong observational evidence of galaxy assembly bias.
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