A deeper dive into the data revealed extreme radio emissions right in the middle of the rattle, along with bright X-rays coming from the same spot, inklings of a huge black hole with a mass of a million suns. She spotted a cosmic baby rattle, a roughly 300-light-year-long bridge of gas connecting two dusty balls swaddling newly coalescing stars. Initially Reines looked at data from the galaxy, called Henize 2-10, in radio and near-infrared wavelengths of light. It was bursting with stars, and Reines was trying to learn more about how these balls of hot gas are born. More than a decade ago, she was in graduate school at the University of Virginia in Charlottesville poring through telescope data on a dwarf galaxy 30 million light-years from Earth. The first hints that they do exist came from a serendipitous find by astronomer Amy Reines. If massive black holes in dwarf galaxies did exist, and if astronomers could find them, those black holes would be an unprecedented window into how the first black holes formed. As time passed, some of those galaxies never grew or merged with others, leaving them unmarred after billions of years of cosmic evolution.Ī wild idea occurred to Volonteri and her colleagues: These galaxies and their black holes were relics of the universe’s birth. In those efforts, almost as soon as they popped into existence, even the smallest galaxies could have surprisingly large black holes. Tipping the scales at only about a trillionth the mass of the Milky Way, they should have relatively runty black holes, or none at all.īut in the late 2000s, astrophysicist Marta Volonteri of Institut d’Astrophysique de Paris at Sorbonne University helped run computer simulations that tracked the evolution of massive black holes from birth to today. In this scenario, the universe’s littlest galaxies, called dwarf galaxies, probably didn’t go through many mergers in the past. A rough estimate puts a supermassive black hole’s heft at somewhere around a thousandth of the mass of its home galaxy. The black holes at the galaxies’ centers grow in lockstep, ballooning as they merge with one another and feed on the newly acquired material. Our current cosmological understanding of how black holes got so big goes something like this: As galaxies grow, collide and merge over cosmic time, they take on gobs of new stars, gas and dust. NASA, ESA, LEAH HUSTAK/STSCI Little galaxies can have big black holes
Earlier this year, astronomers spotted a black hole weighing millions of suns that they believe had been ejected from its host galaxy, leaving a trail of stars (as seen in this illustration). “Without understanding what black holes are doing, you cannot understand galaxy evolution,” says Xiaohui Fan, a cosmologist at the University of Arizona in Tucson, making it impossible to explain the landscape of the universe. If so, they are a tool for probing one of the greatest mysteries in all of astrophysics - how the cosmic Kammapas we see today came to be. Perhaps these black holes aren’t merely cosmic nonconformists but instead big players in the story of our universe. Even more intriguing, astronomers have spotted evidence of black holes wandering at their galaxies’ edges, and in rare cases, being kicked from their homes into intergalactic space. Astronomers have turned up signs of a number of unexpectedly massive black holes in the universe’s tiniest galaxies, and surprisingly, some of those black holes don’t appear to sit at their galaxies’ centers. But now, the existence of these misfits isn’t so easy to ignore. The notion remained just an idea for years. “We can, weirdly, the super-beginning of the universe by looking at things really close to us,” says theoretical astrophysicist Jillian Bellovary of Queensborough Community College in New York City. If observations show that these unusual black holes exist in the nearby universe, these astrophysicists speculated, they could be untapped clues to the universe’s infancy and adolescence. But others weren’t so certain the oddballs should be cast off.
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