In a galaxy (really) far, far away—more than half way across the visible universe or at least 7.6 billion light years—a flood of light (high-energy gamma rays from a blazar) began its trip to Earth. Light from the blazar*, captured in April by NASA's Fermi satellite and the VERITAS and MAGIC telescopes in Amado, Arizona, and in the Canary Islands, Spain, respectively, is one of the farthest sources of high-energy light detected by a gamma-ray telescope on the ground from a galaxy, named PKS 1441+25, so distant.
The Force Awakens Barnard Astrophysicists
Barnard’s Helen Goodhart Altschul Professor of Physics and Astronomy, Reshmi Mukherjee, is the international VERITAS spokesperson and her group has been a leader in publishing this research.
"This study, carried out concurrently with colleagues at MAGIC in Spain and NASA's Fermi satellite, tells the story of a great escape. The gamma rays that travelled billions of light years, avoiding obliteration in the cosmic fog (generated by astrophysical objects such as stars and galaxies that emit light), gives us an opportunity to learn about the star formation history of the Universe," Mukherjee said.
This needle in a haystack, so to speak, was studied by Manel Errando, a post-doctoral research scientist who, at the time, was working under Mukherjee’s supervision at Barnard. Errando analyzed data from the VERITAS telescope and the Fermi-LAT satellite, and participated in the interpretation of the results. He is also a corresponding author of the article published in the Astrophysics Journal Letters.
"With such a distant galaxy, you are usually happy to catch enough photons (particles) to be able to detect it, but this flare of PKS 1441+25 was so bright, and it lasted long enough for us to collect enough data to learn a lot about how the gamma-ray emission was produced. Additionally, the changes in brightness appears to be very synchronized, which means that the shocks producing gamma rays are stronger and more efficient than previously assumed,” says Errando.
Students Support VERITAS Research
This chance happening is being celebrated by Barnard students who work with the Mukherjee and the VERITAS group at Barnard and Columbia through their own research pursuits and as a part of the Summer Research Institute. Students like Isabella Illari ’17 and Jing Luo '17 have been writing code, conducting data analysis and building telescope parts with the VERITAS research group at Barnard. Additionally, Giuliana Noto '18 has spent time analyzing data from NASA's Fermi Satellite.
"I feel extremely lucky to have been given the opportunity to conduct research alongside the VERITAS team this past summer where I analyzed gamma-ray sources previously captured by the Fermi satellite, and isolated sources of energy that could be potentially viewed by the ground-based VERITAS telescopes. And while data analysis may sometimes seem intangible, this discovery not only makes the array of numbers tangible, but also serves as an amazing reminder of the constant possibility of breakthrough within the field of gamma-ray astronomy. Moreover, the discovery underscores the opportunities Barnard students can be involved in the leading physics and astrophysics research and beyond," Noto said.
Read the full NASA press release.
*Blazars are tremendous light beacons powered by super-massive black holes.