The Clustering of Submillimeter Galaxies Detected with ALMA

Abstract

Abstract Previous studies measuring the clustering of submillimeter galaxies (SMGs) have based their measurements on single-dish-detected sources, finding evidence for strong clustering. However, ALMA has revealed that, due to the coarse angular resolution of these instruments, single-dish sources can be composed of multiple sources. This implies that the clustering inferred from single-dish surveys may be overestimated. Here, we measure the clustering of SMGs based on the ALESS survey, an ALMA follow-up of sources previously identified in the LABOCA ECDFS Submillimeter Survey (LESS). We present a method to measure the clustering of ALMA sources that have been previously identified using single-dish telescopes, based on forward modeling both the single-dish and the ALMA observations. We constrain upper limits for the median mass of halos hosting SMGs at 1 < z < 3, finding for SMGs with flux densities mJy, which is at least times lower than the mass inferred based on the clustering of the LESS sources alone. This suggests that the strength of SMG clustering based on single-dish observations was overestimated, and therefore SMGs might be hosted by dark matter halos less massive than has previously been estimated. By extrapolating our models down to flux densities of mJy, we find that such SMGs inhabit halos with median mass . We conclude that only the brightest ( mJy) SMGs would trace massive structures at z ∼ 2 and only SMGs with mJy may be connected to massive local elliptical galaxies, quasars at intermediate redshifts, and high-redshift star-forming galaxies, whereas fainter SMGs are unlikely linked to these populations.