Origins of the extragalactic background at 1mm from a combined analysis of the AzTEC and MAMBO data in GOODS-N

TL;DR

This study combines AzTEC and MAMBO data to analyze the cosmic infrared background at 1mm, identifying the galaxy populations responsible and their redshift distribution, revealing most originate from galaxies at z > 1.3.

Contribution

It provides the first combined 1.16mm map from AzTEC and MAMBO, resolving a significant fraction of the background and constraining the redshift distribution of contributing galaxies.

Findings

Resolved 31-45% of the 1.16mm background.

Most background comes from galaxies at z > 1.3.

Resolved 40-64% of the 850um background.

Abstract

We present a study of the cosmic infrared background, which is a measure of the dust obscured activity in all galaxies in the Universe. We venture to isolate the galaxies responsible for the background at 1mm; with spectroscopic and photometric redshifts we constrain the redshift distribution of these galaxies. We create a deep 1.16mm map (sigma ~ 0.5mJy) by combining the AzTEC 1.1mm and MAMBO 1.2mm datasets in GOODS-N. This combined map contains 41 secure detections, 13 of which are new. By averaging the 1.16mm flux densities of individually undetected galaxies with 24um flux densities > 25uJy, we resolve 31--45 per cent of the 1.16mm background. Repeating our analysis on the SCUBA 850um map, we resolve a higher percentage (40--64 per cent) of the 850um background. A majority of the background resolved (attributed to individual galaxies) at both wavelengths comes from galaxies at z > 1.3. If the ratio of the resolved submillimeter to millimeter background is applied to a reasonable scenario for the origins of the unresolved submillimeter background, 60--88 per cent of the total 1.16mm background comes from galaxies at z > 1.3.