Galaxy forming stars at ferocious rate

A galaxy giving birth to new stars at a ferocious rate has been spotted by NASA astronomers. Dubbed Sparky, the fully-developed elliptical galaxy is a gas-deficient mass of ancient stars which astronomers think developed from the inside out, with a compact core marking its beginnings. Because the core is so distant, the light from the forming galaxy that is observable from Earth was actually created 11 billion years ago, just 3 billion after the Big Bang. “We really hadn’t seen a formation process that could create things that are this dense,” said Erica Nelson of Yale University and lead author of the study published in Nature. “We suspect that this core-formation process is a phenomenon unique to the early universe because the early universe, as a whole, was more compact. Today, the universe is so diffuse that it cannot create such objects anymore.” The galaxy’s composition was revealed by the Hubble and Spitzer space telescopes, archival far infrared images from the latter and Herschel allowed them to determine how quickly the galaxy core is forming stars. Sparky produced around 300 stars annually, compared to 10 by our Milky Way, but is a fraction of its size – 6,000 light years across, compared to 100,000 light years – and contains twice as many stars. “They’re very extreme environments,” Nelson said. “It’s like a medieval cauldron forging stars. There’s a lot of turbulence, and it’s bubbling. If you were in there, the night sky would be bright with young stars, and there would be a lot of dust, gas, and remnants of exploding stars. To actually see this happening is fascinating.” Astronomers believe this frenzied birth was sparked by a torrent of gas flowing into the core while it formed deep inside a gravitational well of dark matter. Observations show the galaxy has been furiously making stars for more than a billion years, but that this will likely slow to a stop as it merges with other galaxies. “I think our discovery settles the question of whether this mode of building galaxies actually happened or not,” said Pieter van Dokkum of Yale University. “The question now is, how often did this occur? We suspect there are other galaxies like this that are even fainter in near-infrared wavelengths. We think they’ll be brighter at longer wavelengths, and so it will really be up to future infrared telescopes such as NASA’s James Webb Space Telescope to find more of these objects.” A massive galaxy in its core formation phase three billion years after the Big Bang