Catching a (radio) wave

In the 1997 science fiction movie “Contact,” Jodie Foster’s character discovers a radio signal emanating from a nearby star system in the search for extraterrestrial intelligence. The message comes as she’s working at the Karl G. Jansky Very Large Array (VLA) telescope in New Mexico.

Although they didn’t swap stories with alien life forms, four MSU Denver students recently got the chance to visit the VLA over spring break to gather information that might just help unlock other unanswered intergalactic mysteries.

Members of the Society of Physics Students joined Grant Denn, associate professor of physics on a recent road trip to the facility, located 50 miles west of Socorro, New Mexico. A joint venture of both MSU Denver and CU Denver, the student organization routinely works to advance research opportunities, build industry connections and provide outreach to high schoolers interested in physics.

A wish fulfilled

For Julia Blackmon, the trip was both an opportunity to gain applied knowledge and the fulfilment of a lifelong wish.

“It’s such a great feeling to be able to do this kind of research as an undergraduate student,” said the junior, who is double-majoring in applied math and biochemistry. “And it was amazing to actually go inside the antenna to appreciate the engineering – I’ve been wanting to visit [the VLA] ever since I learned about it as a kid!”

Denn’s collaboration with a colleague at Macalester College in Minnesota has led to his development of a class in astronomical techniques using VLA-related methodology (to be introduced in Spring of 2018). After submitting an application with scientific justification to conduct related research, Denn and SPS students were granted a window of time to use the VLA themselves.

“It’s a real opportunity for our students to get to use a national instrument like this,” said Denn.

Seeing the frequency

When thinking about telescopes, it’s easy to imagine peering into a glass eyepiece through a tube pointed up to the heavens.

But in contrast to these optical cousins (which students also were able to use during a side trip to New Mexico Institute of Mining and Technology), a radio telescope like the VLA measures a specific portion of the electromagnetic spectrum, Denn explained.

This single telescope actually consists of 27 separate receivers, each more than 80 feet in diameter, arranged in a Y-shaped configuration spread across the desert floor. To create a composite reading, individual dishes are synchronized and collect information in a process referred to as interferometry. The data are subsequently analyzed and “stitched” together.

“The amount of knowledge that goes into the VLA is a marvel of engineering,” said Michael Roos, a senior double-major in physics and applied math who also participated in the outing. “It’s really incredible to meet people who have this kind of systems-level of understanding.”

The result is a comprehensive mosaic of information, and one that could shed light on a very particular corner of our universe.

An ambulatory story

In the Ursa Major constellation, you’ll find the well-studied M81 galaxy. Near that, however, is UGC8245 – a small, irregular dwarf galaxy with the peculiar characteristic of appearing to travel toward Earth, instead of away.

With help from the VLA data collected during the trip, MSU Denver students may contribute to a better understanding of this celestial movement.

According to Denn, this is done by measuring the velocity of neutral hydrogen from a star system. With a sensitivity to this extremely cold material before its formation into stars, the VLAs can essentially gauge movement by looking at the spectrum and taking a picture at each velocity. The resulting phenomenon is the Doppler effect, familiar to anyone who has heard the way sirens sound differently when approaching and then receding.

“This galaxy hasn’t been studied at this wavelength before,” said Denn. “[Our research] could contribute to the larger picture of dwarf galaxies.”

Keep looking up

The potential impact of these research findings could help nudge advances in both mapping the cosmos and exploring it further. And for future physicists, experiencing the process behind it all is invaluable.

For Blackmon, the ability to reconstruct the galaxy’s yearbook photo is a great interdisciplinary exercise.

“The Python-based language [computer code] we’re using for signal processing relates to the kind of research I’ve been able to do in both chemistry and math,” she said. “It’s cool to use the same techniques, and amazing what we can do with them.”

If we do make contact with another interstellar species, it’ll likely be due to the kind of research-based inquiry these MSU Denver students are conducting. Until then, we’ll need to rely upon the advances of our own knowledge to improve life on Earth now, while we search for it elsewhere.

“Space is the reason any curious person looks up,” said Roos. “And humans are pretty amazing – when we choose to be.”