Palomar Observatory

Pomona College and Caltech have received a $9 million grant from the National Science Foundation to build a next-generation exploration system for the historic Palomar Observatory, giving a huge boost to the search for supernovae, near-Earth asteroids, variable stars and other exotic astrophysical phenomena.

Known as the Zwicky Transient Facility, the project will create the premier device worldwide for astronomers to identify rare and fast-changing cosmic events. 

Students also will benefit from the project by getting access to data from sophisticated telescopes and instruments typically reserved for more senior researchers, offering them a taste of the excitement of scientific discovery.

"Our goal is basically to train the next generation of instrument scientists for astronomy," says Bryan Penprase, Pomona's Frank P. Brackett Professor of Astronomy and one of four co-investigators for the grant. "There's a lot of technical know-how that you have to get through to be able to make sense of the sky. And rather than just seeing that in a classroom, we're going to have it connected directly to the research, so they'll immediately have an application for what they learned."

The Zwicky Transient Facility, or ZTF, will discover thousands of astronomical sources known as transients, celestial objects and events that evade traditional observation methods because they vary dramatically in brightness or position over relatively short amounts of time. They include the brilliant but fleeting flash of a supernova caused by a collapsing star, or the periodic flicker of an eclipsing star in orbit around a black hole.

The ZTF will detect these short-lived changes in the night sky by creating a coordinated array of optical telescopes located at Caltech's Palomar Observatory in San Diego County. Each night, the observatory will capture images of large regions of the sky at several different times.  The photos are then sent at high speed to the Caltech campus, where banks of computers comb through the images using artificial intelligence programs that compare successive shots of the same portion of the sky.

 Once a potential transient is picked out, the system then checks follow-up images from Palomar, taken of the same location where the source was first detected. A list of targets is sent to researchers at the project's partner institutions around the world, who can then train their own telescopes on the coordinates to confirm the new discoveries.

"It's an entirely new kind of astronomy," says Penprase. "It's not the obvious approach, where if you just build a bigger telescope you'll see fainter stuff. Instead, the ZTF will be able to sift through days and weeks and months of data to find things that are changing in a brilliant new way."

Development of a more powerful camera, to be installed on the observatory's 48-inch Oschin Schmidt telescope, as well as enhanced software analysis capabilities, will capture more than six times the area of the current device per shot, allowing scientists to survey the entire sky of the Northern Hemisphere in just a single night.

By operating across a wide range of time scales, the Zwicky machine (named for late Caltech/Palomar astronomer Fritz Zwicky) will enable astronomers to locate exotic and unfamiliar objects that would have been missed in earlier studies, due to their rapid appearance and departure. Researchers expect that the enhanced facility will soon discover astronomical sources that have never before been studied or identified, along with providing new insights into phenomena such as explosive gamma-ray bursts, which are still poorly understood.

The award also will support a summer-long undergraduate research program in observational astronomy, with Penprase as the head coordinator. Beginning in summer 2015, astrophysics students from Pomona and Harvey Mudd colleges will join peers from Caltech and other universities in Southern California for an intensive weeklong institute, where they will be trained in the latest techniques in data analysis and instrumentation for large-sky astronomy surveys.

Afterwards, students will return to their home institutions and use their new skills in faculty-led projects that contribute to the Zwicky system's implementation, tackling everything from building and testing camera parts, to using Pomona's own 1-meter telescope at Table Mountain to verify potential transients that were first spotted by the ZTF. The program will culminate in a closing conference, where undergraduates will share their work with each other and showcase their findings to graduate students and astronomy scholars.

According to Penprase, the initiative is designed to forge a pipeline of well-trained students who can pursue careers in astrophysics, aided by a network of peers. And with predictions that the ZTF will locate a new supernova every 24 hours, Penprase is optimistic that Pomona students will soon be making dramatic findings of their own.

"These undergraduates will be controlling some of the largest telescopes in the world. I think a lot of it will be really exciting, because the technology is so advanced and the discoveries are so common," says Penprase. "In just one night they're discovering hundreds of new sources, and that's just an incredible thing for a student to be able to say, ‘I discovered that thing in the sky that no one else has ever seen before.'"