Nomen non est omen: Why it is too soon to identify ultra-compact objects as black holes

TL;DR

This paper argues that current observational data are insufficient to definitively identify ultra-compact objects as black holes and discusses how semiclassical gravity may favor horizonless alternatives.

Contribution

It critically examines the criteria for black hole identification and explores how semiclassical gravity supports horizonless models over traditional black hole interpretations.

Findings

Current data do not conclusively confirm black hole nature.

Semiclassical gravity favors horizonless configurations.

Further observational evidence is necessary for definitive identification.

Abstract

Black holes play a pivotal role in the foundations of physics, but there is an alarming discrepancy between what is considered to be a black hole in observational astronomy and theoretical studies. Despite claims to the contrary, we argue that identifying the observed astrophysical black hole candidates as genuine black holes is not justified based on the currently available observational data, and elaborate on the necessary evidence required to support such a remarkable claim. In addition, we investigate whether the predictions of semiclassical gravity are equally compatible with competing theoretical models, and find that semiclassical arguments favor horizonless configurations.