HD1 is a purported high-redshift galaxy. The galaxy, along with HD2, was published by astronomers at the University of Tokyo in 2022. It is an extremely distant galaxy; the oldest and most distant found in the observable universe, and has an spectroscopic redshift of z = 13. HD1 formed around 330 million years after the Big Bang. HD2 was found to be about the same distance, so it likely formed around the same time. The previously farthest known galaxy, GN-z11, was discovered in 2016. According to the original researchers, "If spectroscopically confirmed, these two sources [ie, HD1 and HD2] will represent a remarkable laboratory to study the Universe at previously inaccessible redshifts." The researchers expect even further clarification of the astronomical objects, including better identifying the objects as galaxies, or, possibly as quasars or black holes, when carefully examined by the upcoming James Webb Space Telescope, Nancy Grace Roman Space Telescope, and GREX-PLUS space missions.
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