Comment on \'Ad\'am et al. (2023): Large fraction of already known systems reported

TL;DR

This paper critiques a recent study by showing that many of its purported new discoveries are actually previously known systems, highlighting issues with false positives due to source blending in dense stellar fields.

Contribution

It provides a detailed re-evaluation of the claimed new systems, identifying numerous false positives caused by blending, and emphasizes the need for careful verification in crowded fields.

Findings

Approximately 25% of the reported doubly eclipsing systems are false positives.

Many supposed new discoveries are actually known systems contaminated by blending.

High false positive rate underscores the importance of rigorous validation in dense stellar regions.

Abstract

In this work, I report that large fraction of stars detected by \'Ad\'am et al. (2023, A&A, 674, A170, arXiv:2304.08394) and noted in that work as new discoveries are in fact known systems. This is especially true for the dense bulge fields with large blending of nearby sources. Among the published 245 stars determined to be doubly eclipsing (i.e. containing two eclipsing signals), I identified 53 blends. In other words, about a quarter of the systems noted by \'Ad\'am et al. (2023, A&A, 674, A170) are not actually doubly eclipsing; rather, these are contaminations of known nearby sources that have already been detected by OGLE. Such a high proportion of reported false positives should not be readily ignored and ought to be addressed in future studies.