A new submm source within a few arcseconds of $\alpha$ Centauri: ALMA discovers the most distant object of the solar system

TL;DR

This paper reports the detection of a new submillimeter source near alpha Centauri using ALMA, confirming its robustness at 445 GHz, but emphasizes the need for further data to determine its nature.

Contribution

The study demonstrates the importance of multiple data reduction methods and $(u,v)$-plane modeling in confirming low signal-to-noise detections of unknown sources.

Findings

Robust detection of the source at 445 GHz with >12σ significance.

Inconsistent detection at 343.5 GHz across different data reductions.

Highlights the necessity of additional data for source characterization.

Abstract

We recently announced the detection of an unknown submillimeter source in our ALMA observations of alpha Cen AB. The source was detected in two epochs, a strong detection at 445~GHz and one at lower significance at 343.5~GHz. After valuable feedback of the community, it turns out that the detection at 343.5~GHz could not be reproduced with a different reduction software nor with fitting within the $(u,v)$-plane. The detection at 445~GHz has been further confirmed with modeling of the $(u,v)$-data and was shown to be robust at $>12\sigma$, confirming our detection of this unknown source. However, based on only one epoch, further analysis and preferably new data are needed, before publication of an article in which the nature of the new source can be discussed. The analysis has indicated the importance of both $(u,v)$-plane fitting and alternative data reduction when dealing with low signal to noise source detections.