Washington: NASA scientists have spotted the farthest known galaxy in the universe, a primitive cluster of stars just 500 million years old.
An intensive survey deep into the universe by NASA’s Hubble and Spitzer space telescopes has yielded the image of the galaxy named SPT0615-JD, stretched and amplified by a phenomenon called gravitational lensing.
Though a few other primitive galaxies have been seen at this early epoch, they have essentially all looked like red dots given their small size and tremendous distances.
However, in this case, the gravitational field of a massive foreground galaxy cluster not only amplified the light from the background galaxy but also smeared the image of it into an arc.
First predicted by Albert Einstein a century ago, the warping of space by the gravity of a massive foreground object can brighten and distort the images of far more distant background objects.
Astronomers use this “zoom lens” effect to go hunting for amplified images of distant galaxies that otherwise would not be visible with today’s telescopes.
SPT0615-JD was identified in Hubble’s Reionization Lensing Cluster Survey (RELICS) and companion S-RELICS Spitzer programme.
“RELICS was designed to discover distant galaxies like these that are magnified brightly enough for detailed study,” said Dan Coe, Principal Investigator of RELICS.
By combining the Hubble and Spitzer data, Salmon calculated the lookback time to the galaxy of 13.3 billion years.
Preliminary analysis suggests the diminutive galaxy weighs in at no more than 3 billion solar masses. It is less than 2,500 light-years across
The object is considered prototypical of young galaxies that emerged during the epoch shortly after the Big Bang.