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Astronomers Spot Farthest Galaxy Known in the Universe

an artist’s conception of the most distant galaxy with a gamma-ray burst.
Credit: Jingchuan Yu

Maunakea, Hawaii – An international team of astronomers using W. M. Keck Observatory have spectroscopic confirmation of the most distant astrophysical object known to date.

The researchers, led by Professor Linhua Jiang at the Kavli Institute for Astronomy and Astrophysics at Peking University, obtained near-infrared spectra with the Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) on the Keck I telescope and successfully measured the distance of a very faint galaxy located 13.4 billion light-years away (redshift of z = 10.957).

Named GN-z11, the galaxy was generally believed to be at a redshift greater than 10, probably closer to 11, based on existing data from NASA’s Hubble Space Telescope. But its exact redshift remained unclear, until now.

The results of the study, which are based on observations made under the time exchange program between Keck Observatory and Subaru Telescope on Maunakea, are published in the December 14, 2020 issue of the journal Nature Astronomy.

During their observations at Keck Observatory, the team also serendipitously detected a bright burst coming from the galaxy. After performing a comprehensive analysis, the team ruled out the possibility that the flash was from any known sources such as man-made satellites or moving objects in the solar system and determined it may have been produced by a gamma-ray burst.

A paper regarding this possible bright ultraviolet flash from GN-z11 is also published in the December 14, 2020 issue of Nature Astronomy.

Both studies are important to understanding the formation of stars and galaxies in the very early universe.

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ABOUT MOSFIRE

The Multi-Object Spectrograph for Infrared Exploration (MOSFIRE), gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this large, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only two billion years after the Big Bang. MOSFIRE was made possible by funding provided by the National Science Foundation. It is currently the most in-demand instrument at Keck Observatory.

ABOUT W. M. KECK OBSERVATORY

The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two 10-meter optical/infrared telescopes on the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.