A new image from the Gemini North telescope on Maunakea in Hawai’i offers the sharpest look yet at a striking pair of interacting spiral galaxies, cataloged as NGC 7253.
This image of NGC 7253 was captured by the Gemini North telescope on Maunakea, one half of the International Gemini Observatory. Image credit: International Gemini Observatory / NOIRLab / NSF / AURA / J. Miller & M. Rodriguez, International Gemini Observatory & NSF’s NOIRLab / T.A. Rector, University of Alaska Anchorage & NSF’s NOIRLab / D. de Martin & M. Zamani, NSF’s NOIRLab.
NGC 7253 is located more than 200 million light-years away in the constellation of Pegasus.
The system was discovered by the German-British astronomer Albert Marth on 9 September 1863.
It consists of two relatively small-looking spiral galaxies separated by roughly four million light-years.
The northern member is generally called NGC 7253A, while the southern member is NGC 7253B.
They are close enough that their mutual gravity disturbs their structures, producing a system sufficiently unusual to be included in Halton Arp’s Atlas of Peculiar Galaxies as Arp 278.
The new image of NGC 7253 was captured by the Gemini North telescope, one half of the International Gemini Observatory, partly funded by NSF and operated by NSF’s NOIRLab.
The picture was produced as part of the NOIRLab Legacy Imaging Program, an initiative that dedicates telescope time specifically to capturing detailed color images of astronomical objects for public outreach.
“NGC 7253 is a fascinating object because it’s two galaxies that are merging into one over billions of years,” said NOIRLab intern Raiyan Rahman.
“But we mainly picked this object because it was one of the few that actually lay within a Hawaiian constellation, Ka Lupe o Kawelo.”
“After spending so much time on Maunakea, it was important to us to pick something that was both culturally and astronomically significant.”
The image reveals two similarly sized spirals, with their wispy arms stretched and warped by the mutual pull of gravity as the galaxies slowly spiral toward a merger that will unfold over billions of years.
Scattered through the frame are bright pink knots of light, marking regions where hydrogen gas has been ionized by intense radiation from newly formed stars.
Such fireworks are typical of galactic collisions: as the two systems draw closer, clouds of gas and dust within their spiral arms collide and compress, triggering bursts of star formation.
The young, hot stars born from this process flood the surrounding gas with radiation intense enough to strip electrons from hydrogen atoms, producing the glowing pink clouds — known to astronomers as HII regions — that thread through the galaxies’ arms in the image.
“Stars are sources of life and health for us as human beings, because our Sun is a star, and we cannot live without it,” said NOIRLab intern Manu Silva-Sampaio.
