Study suggests early-universe red dots may be galaxy cores hidden by distance

Astronomers have long puzzled over the compact, bright red sources identified in the early universe by the James Webb Space Telescope. In a new paper, Pierluigi Rinaldi and collaborators studied a lower-redshift spiral galaxy, WISEA J123635.56+621424.2, nicknamed the “Saguaro,” whose central red region mirrors those distant dots. Combining Hubble ultraviolet images with Webb infrared data and Chandra X-ray observations, they confirmed the nucleus exhibits the same spectral traits as the high-redshift dots, including weak X-ray emission.

When the team digitally shifted the galaxy to higher redshift, its outer structure vanished, leaving only the bright core detectable. This suggests that observational bias, rather than a separate galaxy population, may explain many of the early-universe red dots. The authors propose that such objects represent a phase of active supermassive black holes within otherwise typical galaxies, offering a link between early-time dots and later-epoch galaxies. Further searches for similar low-redshift analogs are planned to test this scenario.