Hubble imaging and spectroscopy of the dwarf starburst galaxy Henize 2-10 clearly show a gas outflow … [+]
NASA, ESA, B. Tully, S. Conti, W
Supermassive black holes (SMBHs) are wondrous behemoths, typically billions of solar masses in size; they’re the universe’s way of reminding us that we are mere specks in this vast cosmic ocean. Lying at the centers of large galaxies like our Milky Way, conventionally they have been known for stymying star production rather than promoting it.
Yet new Hubble Space Telescope observations confirm that a supermassive black hole in the center of Henize 2-10, a dwarf starburst galaxy some 30 million light years away, harbors a one million solar mass black hole that is triggering significant amounts of star formation.
Researchers at Montana State University in Bozeman detail their observations in a paper appearing this week in the journal Nature. They note that the SMBH in this small galaxy in the southern constellation of Pyxis is actually aiding in the creation of stars rather than just gobbling them up, says NASA.
A pullout of the central region of dwarf starburst galaxy Henize 2-10 traces an outflow, or bridge … [+]
NASA, ESA, Zachary Schutte (XGI), Amy Reines (XGI); Image Processing: Alyssa Pagan (STScI)
“These are the first observations of star formation being triggered by an outflow from a supermassive black hole in a dwarf galaxy,” Zachary Schutte, the paper’s lead author and a graduate physics student at Montana State University, told me. This phenomenon has been observed in larger galaxies but until our work it was unknown if outflows from supermassive black holes could cause star formation in lower mass dwarf galaxies, he says.
“Hubble has provided a very clear picture of the connection between the black hole and a neighboring star forming region located 230 light-years from the black hole,” Amy Reines, the paper’s co-author and an astrophysicist at Montana State University in Bozeman, said in a statement. “Hubble’s amazing resolution clearly shows a corkscrew-like pattern in the velocities of the gas, which we can fit to the model of a wobbling, outflow from a black hole.”
In larger galaxies, this effect is just the opposite, as material falling toward the black hole is whisked away by surrounding magnetic fields, forming blazing jets of plasma moving at close to the speed of light, says NASA. Gas clouds caught in the jets’ path would be heated far beyond their ability to cool back down and form stars, notes the space agency. But that didn’t happen with Henize 2-10 since its central black hole apparently has a gentler outflow which creates just enough compression to precipitate new star formation.
The study of such small dwarf galaxies could help theorists better understand how supermassive black holes first evolved in the early universe.
Such dwarf galaxies, which have remained small over cosmic time, may shed light on the question of how the first seeds of supermassive black holes formed and evolved over the history of the universe, says NASA.
“The era of the first black holes is not something that we have been able to see, so it really has become the big question: where did they come from? Dwarf galaxies may retain some memory of the black hole seeding scenario that has otherwise been lost to time and space,” Reines said in a statement.
