An international team of researchers, led by Physics and Astronomy professor Sarah Gallagher, has detected the most energetic wind from any quasar ever measured – an outflow travelling at nearly 13 per cent of the speed of light with enough energy to dramatically impact star formation across an entire galaxy.
The extragalactic tempest lay hidden in plain sight for 15 years before being unveiled by innovative computer modeling and new data from the international Gemini Observatory on Hawai’i’s Maunakea.
“While high-velocity winds have previously been observed in quasars, these have been thin and wispy, carrying only a relatively small amount of mass,” said Gallagher, a Science Advisor to the President of the Canadian Space Agency. “The outflow from this quasar, in comparison, sweeps along a tremendous amount of mass at incredible speeds. This wind is crazy powerful, and we don’t know how the quasar can launch something so substantial.”
The discovery was made using observations from the international Gemini Observatory, a program of National Science Foundation’s NOIRLab. This powerful outflow stems from a quasar known as SDSS J135246.37+423923.5 which lies roughly 60 billion light-years from Earth.
The team was also able to infer the mass of the supermassive black hole powering the quasar. This monstrous object is 8.6 billion times as massive as Earth’s Sun – about 2,000 times the mass of the black hole in the center of our Milky Way and 50 per cent more massive than the well-known black hole in the galaxy Messier 87.
This study, Discovery of a Remarkably Powerful Broad Absorption-line Quasar Outflow in SDSS J135246.37+423923.5, was recently published in the journal Astrophysical Journal.
Quasars – also known as quasi-stellar objects – are a type of extraordinarily luminous astrophysical object residing in the centres of massive galaxies. Consisting of a supermassive black hole surrounded by a glowing disk of gas, quasars can outshine all the stars in their host galaxy and can drive winds powerful enough to influence entire galaxies.
“Some quasar-driven winds have enough energy to sweep the material from a galaxy that is needed to form stars and thus quench star formation,” said Hyunseop (Joseph) Choi, a graduate student at the University of Oklahoma and the first author of the scientific paper on this discovery. “We studied a particularly windy quasar, SDSS J135246.37+423923.5, whose outflow is so thick that it’s difficult to detect the signature of the quasar itself at visible wavelengths.”
Despite the obstruction, the team was able to get a clear view of the quasar using the Gemini Near-Infrared Spectrograph (GNIRS) on Gemini North to observe at infrared wavelengths. Using a combination of high-quality spectra from Gemini and a pioneering computer-modeling approach, the astronomers uncovered the nature of the outflow from the object – which proved, remarkably, to be more energetic than any quasar outflow previously measured.
The team’s discovery raises important questions, and also suggests there could be more of these quasars waiting to be found.
“We don’t know how many more of these extraordinary objects are in our quasar catalogs that we just don’t know about yet,” Choi said. “Since automated software generally identifies quasars by strong emission lines or blue color – two properties our object lacks – there could be more of these quasars with tremendously powerful outflows hidden away in our surveys.”