A recently found galaxy is so far away, astronomers see it the way that it looked when the universe was only 600 million years old.
Galaxy A2744_YD4 appears to hold enough of this stardust to make 6 million suns, while the mass of the galaxy’s stars add up to 2 billion times the mass of the sun. Baby stars in A2744_YD4 are popping up at a rate of 20 solar masses per year, which is 20 times faster than the current rate of star formation in the Milky Way.
“This rate is not unusual for such a distant galaxy, but it does shed light on how quickly the dust in A2744_YD4 formed,” study co-author Richard Ellis, of ESO and University College London, said in the statement. “Remarkably, the required time is only about 200 million years — so we are witnessing this galaxy shortly after its formation.”
That means stars began to form 200 million years before the light from A2744_YD4 reached ALMA’s telescope array, making the stardust that astronomers can see the remnants of some of the earliest stars in the universe, the researchers said.
“With ALMA, the prospects for performing deeper and more extensive observations of similar galaxies at these early times are very promising,” Ellis said.