The LABOCA Survey of the Extended Chandra Deep Field-South: Clustering of Submillimetre Galaxies

We present a measurement of the spatial clustering of submillimetre galaxies (SMGs) at z = 1–3. Using data from the 870 μm LABOCA submillimetre survey of the Extended Chandra Deep Field South, we employ a novel technique to measure the cross-correlation between SMGs and galaxies, accounting for the full probability distributions for photometric redshifts of the galaxies. From the observed projected two-point cross-correlation function we derive the linear bias and characteristic dark matter halo masses for the SMGs. We detect clustering in the cross-correlation between SMGs and galaxies at the \u3e 4σ level. Accounting for the clustering of galaxies from their autocorrelation function, we estimate an autocorrelation length for SMGs of r0 = 7.7 +1.8 −2.3 h −1 Mpc assuming a power-law slope γ = 1.8, and derive a corresponding dark matter halo mass of log(Mhalo[h M⊙]) = 12.8 +0.3 −0.5. Based on the evolution of dark matter haloes derived from simulations, we show that that the z = 0 descendants of SMGs are typically massive (∼ 2–3 L) elliptical galaxies residing in moderateto high-mass groups (log(Mhalo[h M⊙]) = 13.3 +0.3 −0.5). From the observed clustering we estimate an SMG lifetime of ∼100 Myr, consistent with lifetimes derived from gas consumption times and star-formation timescales, although with considerable uncertainties. The clustering of SMGs at z ∼ 2 is consistent with measurements for optically-selected quasi-stellar objects (QSOs), supporting evolutionary scenarios in which powerful starbursts and QSOs occur in the same systems. Given that SMGs reside in haloes of characteristic mass ∼ 6× 10 h M⊙, we demonstrate that the redshift distribution of SMGs can be described remarkably well by the combination of two effects: the cosmological growth of structure and the evolution of the molecular gas fraction in galaxies. We conclude that the powerful starbursts in SMGs likely represent a short-lived but universal phase in massive galaxy evolution, associated with the transition between cold gas-rich, star-forming galaxies and passively evolving systems