Document Type

Article

Publication Date

6-1-2012

Publication Title

Monthly Notices of the Royal Astronomical Society

Abstract

The source counts of galaxies discovered at submillimetre and millimetre wavelengths provide important information on the evolution of infrared-bright galaxies. We combine the data from six blank-field surveys carried out at 1.1mm with AzTEC, totalling 1.6deg in area with root-mean-square depths ranging from 0.4 to 1.7mJy, and derive the strongest constraints to date on the 1.1 mm source counts at flux densities S = 1-12mJy. Using additional data from the AzTEC Cluster Environment Survey to extend the counts to S ∼ 20mJy, we see tentative evidence for an enhancement relative to the exponential drop in the counts at S ∼ 13mJy and a smooth connection to the bright source counts at >20mJy measured by the South Pole Telescope; this excess may be due to strong-lensing effects. We compare these counts to predictions from several semi-analytical and phenomenological models and find that for most the agreement is quite good at flux densities ≳ 4mJy; however, we find significant discrepancies (≳ 3σ) between the models and the observed 1.1-mm counts at lower flux densities, and none of them is consistent with the observed turnover in the Euclidean-normalized counts at S ≲ 2mJy. Our new results therefore may require modifications to existing evolutionary models for low-luminosity galaxies. Alternatively, the discrepancy between the measured counts at the faint end and predictions from phenomenological models could arise from limited knowledge of the spectral energy distributions of faint galaxies in the local Universe.

Keywords

Galaxies: evolution, Galaxies: high-redshift, Galaxies: starburst, Submillimetre: galaxies

Volume

423

Issue

1

First Page

575

Last Page

589

DOI

10.1111/j.1365-2966.2012.20905.x

ISSN

00358711

Rights

© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS. 2 1100 1100 1100 1100

Comments

Archived as published.

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

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.