UC Berkeley researchers find brightest, closest supernova in years

A supernova — discovered by the Palomar Transient Factory — is the closest of its kind found in almost 40 years. It will not be visible to the naked eye in a week or two.
Lawrence Berkeley National Laboratory/Courtesy
A supernova — discovered by the Palomar Transient Factory — is the closest of its kind found in almost 40 years. It will not be visible to the naked eye in a week or two.

Astronomers from UC Berkeley and Lawrence Berkeley National Laboratory helped find a “holy grail” Wednesday night when they discovered a supernova relatively close to Earth.

The supernova — discovered by the Palomar Transient Factory, a four-year-long survey operated from the Palomar Observatory in California — is the brightest and closest of its kind found in almost 40 years. It is located in the Pinwheel Galaxy, just over 20 million light years away.

“You can’t hope to find something like this,” said survey team leader Peter Nugent, a scientist at Berkeley Lab and campus adjunct professor of astronomy.

“Literally the last time something like this happened, I was a freshman in college. Something like this, you just don’t bank on it.”

He said the program usually finds several supernovae nightly, but nothing as close or bright as this discovery.

The project involves a collaboration between institutions, including UC Berkeley, the Berkeley lab and Oxford University. The project takes about 40 gigabytes of digital images nightly, covering about 600 square degrees of the sky, or 1,200 Earth moons. The data is then transferred from the observatory to the National Energy Research Scientific Computing Center at Berkeley lab. Researchers compare past and recent images and search for any differences in the pictures.

According to Brad Cenko, a postdoctoral researcher at UC Berkeley and a collaborator in the survey, the project had two main goals — to identify transient sources like supernovae and novae to improve other studies in the field and to find new variable phenomena that have never been seen.

“This is a pretty rare occurrence,” Cenko said. “It would fall more in that latter category (of goals) — that needle in a haystack, very rare but very rewarding discovery.”

Nugent said that the program received data from the observatory on the supernova, and within hours, other collaborators on the project were sent coordinates for follow-up observations. The first spectra of the explosion were observed by telescopes in the Canary Islands by Oxford collaborators, followed by telescopes at the Lick Observatory in California and the Keck Observatory in Hawaii.

In the aftermath of the supernova’s initial explosion, it will continue to get brighter, according to Joshua Bloom, a collaborator with the project and an assistant professor of astronomy at UC Berkeley. He added that in a week or two, while the supernova will not be visible to the naked eye, it will be bright enough to be detected by individuals with a small telescope.

“In that sense, it opens up the possibility for amateurs to get involved,” Bloom said. “It’s not just an esoteric supernova that somebody with the biggest telescope can observe — it’s a supernova for everybody.”

This sighting will give researchers a better understanding of the progenitor solar system from which the supernova developed. Additionally, researchers will be able to make some key observations about the acceleration of the expansion of the universe.

Researchers will continue to study the supernova as it brightens and expands. However, because of its current proximity to the sun, the supernova will only be visible for about one more month before it will be hidden from view for three months. Because it is so close to Earth, observation can then continue periodically for over a decade until it eventually fades away.

“It’s kind of quickly on its way to becoming a classic supernova,” Bloom said. “This is just the beginning of what’s going to be a very long affair with a very close-by explosive event.”