The Digital Press

Astronomers developed a method to identify quasars with consistent long-term variability using just two infrared survey epochs, capturing a sample of about 2,500 quasars. This approach, including a new Gaia-based sample called Quaia, confirms typical quasar variability patterns and improves identification of reddened quasars.

Why it matters: Efficiently finding variable quasars aids understanding their physical properties and detecting reddened, often overlooked, objects.

The big picture: Infrared data over 20 years reveals typical quasar variability trends consistent with previous optical studies.

Stunning stat: About 11% of selected quasars show no variability in detailed optical monitoring, indicating low contamination.

Quick takeaway: Two-epoch infrared variability selection robustly identifies diverse quasars, including many newly studied ones from the Quaia sample.