Document Type

Article

Publication Date

3-1-2009

Publication Title

Monthly Notices of the Royal Astronomical Society

Abstract

We report an overdensity of bright submillimetre galaxies (SMGs) in the 0.15 deg AzTEC/COSMOS survey and a spatial correlation between the SMGs and the optical-IR galaxy density at z ≲ 1.1. This portion of the COSMOS field shows a ∼3σ overdensity of robust SMG detections when compared to a background, or 'blank-field', population model that is consistent with SMG surveys of fields with no extragalactic bias. The SMG overdensity is most significant in the number of very bright detections (14 sources with measured fluxes S > 6 mJy), which is entirely incompatible with sample variance within our adopted blank-field number densities and infers an overdensity significance of ≫ 4σ. We find that the overdensity and spatial correlation to optical-IR galaxy density are most consistent with lensing of a background SMG population by foreground mass structures along the line of sight, rather than physical association of the SMGs with the z ≲ 1.1 galaxies/clusters. The SMG positions are only weakly correlated with weak-lensing maps, suggesting that the dominant sources of correlation are individual galaxies and the more tenuous structures in the survey region, and not the massive and compact clusters. These results highlight the important roles cosmic variance and large-scale structure can play in the study of SMGs.

Keywords

Cosmology: miscellaneous, Galaxies: evolution, Gravitational lensing, Infrared: galaxies, Submillimeter, Surveys

Volume

393

Issue

4

First Page

1573

Last Page

1583

DOI

10.1111/j.1365-2966.2008.14284.x

ISSN

00358711

Rights

© 2009 The Authors. Journal compilation © 2009 RAS. 2 1.1 mm

Comments

Archived as published.

No commercial reproduction, distribution, display or performance rights in this work are provided.

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