The Herschel Cold Debris Disks: Confusion with the Extragalactic Background at 160 mu

TL;DR

This study investigates whether cold debris disk candidates detected by Herschel are genuine or confused with background galaxies and IR cirrus, concluding that confusion explains the observations.

Contribution

The paper provides evidence that Herschel cold debris disk detections are likely due to confusion with background sources rather than actual debris disks.

Findings

Confusion with background galaxies explains Herschel cold debris disk signals.

Conventional debris disk models cannot fit the observed spectral energy distributions.

Background contamination is a significant factor in interpreting Herschel data.

Abstract

The Herschel "DUst around NEarby Stars (DUNES)" survey has found a number of debris disk candidates that are apparently very cold, with temperatures near 22K. It has proven difficult to fit their spectral energy distributions with conventional models for debris disks. Given this issue we carefully examine the alternative explanation, that the detections arise from confusion with IR cirrus and/or background galaxies that are not physically associated with the foreground star. We find that such an explanation is consistent with all of these detections.