The Ghostly Remnants of Galaxy Interactions Uncovered in a Nearby Galaxy Group

Astronomers using the Subaru Telescope's Hyper Suprime-Cam prime-focus camera recently observed the nearby large spiral galaxy M81, together with its two brightest neighbors, M82 and NGC 3077. The results of their observations are deep, super wide-field images of the galaxies and their populations of young stars. As part of a Galactic Archaeology study, the team discovered that the spatial distribution of the young stars around these galaxies follows very closely that of their distribution of neutral hydrogen. “This is the first endeavor beyond the Local Group of galaxies to demonstrate the hierarchical galaxy assembly process on galactic scales,” said team member Dr. Sakurako Okamoto (Shanghai Astronomical Observatory).

Pseudo-color images from HSC observation which contains M81, M82, and NGC 3077. Diameter of the FOV is 1.5 degrees.
Pseudo-color images from HSC observation which contains M81, M82, and NGC 3077. Diameter of the FOV is 1.5 degrees. Original size (264KB)
Neighborhood of the spiral galaxy M81 (Credit: NAOJ/HSC Project)

The research paper titled “A Hyper Suprime-Cam View of the Interacting Galaxies of the M81 Group” will be published in the Astrophysical Journal Letters.

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