Determine Teleios’s integrated radio spectral index

Determine the integrated radio spectral index of the full structure of the Galactic supernova remnant Teleios (G305.4–2.2) by obtaining radio-continuum observations that properly sample the entire angular extent at both low (e.g., ∼150 MHz) and GHz (e.g., ∼943.5 MHz) frequencies, including recovery of short spatial baselines, so that the global spectral index can be measured reliably without missing large-scale flux.

Background

The current estimate of Teleios’s spectrum was derived from the excess in its bright ring using ASKAP at 943.5 MHz and GLEAM-X at 151.5 MHz. Due to missing short baselines and large-scale Galactic background fluctuations, only the ring’s excess flux could be measured, yielding a relatively uncertain spectral index of α = −0.6 ± 0.3.

The authors explicitly state that the total spectral index of the full structure is unknown under current data sampling. A robust integrated spectral index requires observations that recover all spatial scales across multiple frequencies.