Researchers identified the first-known "changing look" quasar that is believed to have a "dimmer switch."
The discovery could provide new insight into quasars, which draw their energy from black holes, Yale University reported. Until this study researchers had not been able to examine both the bright and dim phases of a quasar from a sole source.
The recently-studied quasar was observed to have dimmed by a factor of between six and seven when compared with past images of the object.
"We've looked at hundreds of thousands of quasars at this point, and now we've found one that has switched off," said C. Megan Urry, Yale's Israel Munson Professor of Astronomy and Astrophysics, and the study's principal investigator. "This may tell us something about their lifetimes."
The fascinating phenomenon was observed during a probe of Stripe 82, which is a region found along the celestial equator.
"This is like a dimmer switch," said Stephanie LaMassa, a Yale associate research scientist. "The power source just went dim. Because the life cycle of a quasar is one of the big unknowns, catching one as it changes, within a human lifetime, is amazing."
The team also observed a weakening of the quasar's broad emission lines, which suggests the black hole essentially went on a "diet" and was giving off less energy. When this occurred the quasar was prompted to hit the dimmer switch, causing most of its emission lines to disappear. The findings reveal secrets of the sporadic nature of black holes.
"It makes a difference to know how black holes grow," Urry said, noting that all galaxies have black holes, and quasars are a phase that black holes go through before becoming dormant. "This perhaps has implications for how the Milky Way looks today."
The researchers noted there is also a chance the quasar will boot up again, creating yet another "look" for the scientists to observe.
"Even though astronomers have been studying quasars for more than 50 years, it's exciting that someone like me, who has studied black holes for almost a decade, can find something completely new," LaMassa concluded.
