We analyze the spectra of 300,000 luminous red galaxies (LRGs) with stellar masses M∗≳1011M⊙ from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). By studying their star-formation histories, we find two 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 large-scale structure environments than slow-growing systems, for a given stellar-mass threshold. Our 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.
@article{arxiv.1705.00013,
title = {Observational evidence of galaxy assembly bias},
author = {Antonio D. Montero-Dorta and Enrique Perez and Francisco Prada and Sergio Rodriguez-Torres and Ginevra Favole and Anatoly Klypin and Roberto Cid Fernandes and Rosa Gonzalez-Delgado and Alberto Dominguez and Adam S. Bolton and Ruben Garcia-Benito and Eric Jullo and Anna Niemiec},
journal= {arXiv preprint arXiv:1705.00013},
year = {2017}
}