Astronomers have found a quasar that shifts between extreme brightness and dimness, which might shed light on how certain objects formed rapidly in the early universe. This quasar is the farthest object identified by the NuSTAR X-ray space telescope (launched in 2012) and is one of the most variable quasars recorded.
A Yale-led team of researchers has discovered a quasar that experiences significant changes in brightness, potentially explaining the rapid growth of some early universe objects.
The announcement made on January 14 at the winter meeting of the American Astronomical Society reveals that this quasar is the most distant object observed by the NuSTAR X-ray space telescope and ranks among the most variable quasars ever detected.
“Our findings suggest that this quasar is likely a supermassive black hole with a jet aimed directly at Earth, and we are observing it from the universe’s first billion years,” explained Lea Marcotulli, a Yale astrophysics postdoc and lead author of a study published on January 14 in The Astrophysical Journal Letters.
Quasars are some of the oldest and brightest entities in the universe. They originate from active galactic nuclei (AGN) — regions at the centers of galaxies where a black hole pulls in surrounding matter — and emit electromagnetic radiation across radio, infrared, visible, ultraviolet, X-ray, and gamma-ray wavelengths. This wide range of visibility makes quasars valuable for exploring the structure and development of the cosmos.
Astronomers use quasars to investigate reionization, a phase occurring less than a billion years after the Big Bang when neutral hydrogen atoms were charged, leading to the illumination of the universe by the first stars.
“The reionization epoch marks the conclusion of the universe’s dark ages,” remarked Thomas Connor, an astronomer at the Chandra X-Ray Center and co-author of the study. “There is ongoing debate regarding the specific timeline and sources responsible for reionization, with actively accreting supermassive black holes being one proposed factor.”
In their research, the team compared observations of a distant quasar — referred to as J1429+5447 — from NuSTAR with earlier observations made four months prior using the Chandra X-ray telescope. They discovered that the quasar’s X-ray emissions had surged, doubling in brightness over that brief period (due to relativistic effects, the four-month interval for observatories corresponded to about two weeks for the quasar).
“Such a dramatic change in X-ray emissions, both in intensity and speed, is extraordinary,” said Meg Urry, the Israel Munson Professor of Physics and Astronomy at Yale and co-author of the study. “This variability is almost certainly due to a jet directed toward us — a stream where particles are propelled up to a million light years from the supermassive black hole’s center. Because the jet travels close to the speed of light, Einstein’s theory of special relativity enhances the observed variability.”
The findings from this study provide critical insights for astronomers examining reionization. Furthermore, they might guide researchers toward identifying other supermassive black holes from the early universe.
“The discovery of additional supermassive black holes possibly harboring jets raises intriguing questions about how these black holes could have grown so large in a relatively brief period and the potential links to the mechanics of jet formation,” Marcotulli noted.
This research was supported by NASA.
