In bowling, three strikes in a row is called a "turkey." Nahum Arav and three members of his Virginia Tech Department of Physics research lab have pulled off a galactic turkey, getting all three of their proposed projects with the Hubble Space Telescope approved for the coming year.
While likely not the first time one research team has pulled off such a feat in the 27-year history of the NASA telescope, Arav said it’s rare and certainly a first for Virginia Tech. The chances of getting a project tasked to the famed NASA space-observatory are one in five, said Arav, who has been working on and off with the Earth-orbiting vehicle since it launched in 1989.
When research is slated for Hubble, the project is not physically placed onto the 24,400-pound space-based projectile. Instead, it is assigned time, or orbits of 1.5 hours each, to use the device’s nearly 8-foot mirror and extraordinarily high-resolution cameras that can see objects in space – free of atmospheric interference that can warp visibility – and produce images and spectra in infrared, visible, and ultraviolet light.
Arav will continue his career-long study of black holes and quasars, the latter being mysterious bursts of light created when matter falls into a black hole, creating something akin to a last jolt of incredible energy.
The largest of the projects designed by Arav will take 40 orbits around Earth, or roughly 65 hours of the Hubble’s time. This effort will focus on extreme ultraviolet radiation coming from 10 quasars to measure the likely impact of quasar outflows on the formation and evolution of galaxies, including our own Milky Way galaxy, which has at its center a massive, dormant black hole known as Sagittarius A*.
“A long time ago, roughly 10 billion years, such a phenomenon helped shape the galaxy we call home,” added Arav, noting that not all of the orbit time is usable.
The second project involves nine orbits around the Earth to take what Arav calls the first-ever images of these same quasar outflows and see their extent and relationship to their host galaxy. The third project focuses not on using Hubble itself, but getting funding for analysis of archival observations by the telescope that tie directly to the same group of 10 quasars.
Arav said all archived images and data from Hubble are open source.
The large amounts of gravitational energy released when matter falls into a super-massive black-hole create light 100 times more luminous than the entire galaxy. That luminescence is a quasar.
Arav said that theorists “have shown that if only 5 percent of this energy is released as mechanical energy, it can be a dominant mechanism in shaping the final formation of the galaxy,” as well as determining the mass of the super-massive black-hole where the quasar originates.
“Due to the results of our research program, these quasar outflows are the leading candidate for the source of this mechanical energy,” he said.
To ensure that researchers are able to best use the Hubble’s time and support resources, NASA funds these projects. Arav’s team, which includes a current doctoral student and a recent doctoral graduate, all part of the Virginia Tech College of Science, will receive $300,000 from NASA’s Space Telescope Science Institute. Funds will help the team analyze the data and imagery for the next two years.
Arav submitted his proposals in March and learned in June that all three of his submissions were accepted. The calendar year for Hubble Space Telescope projects begins in September.
Arav and his team will not observe the Hubble’s orbits in real time. Program scientists form the Space Telescope Science Institute handle all observations and data and imagery collection. “Shortly after that we download the data from the institute, and then we have a proprietary period of one year to work on the data exclusively,” said Arav. “After that, anyone can download the data and try to analyze it.
“The analysis is very challenging and for that, during the past 10 years, we built state-of-the-art scientific software that allows us to tease the science out of the data,” added Arav.
The team is changing this year as the Hubble projects move forward. On Aug. 1, Arav departed for a full-year sabbatical at Technion, the Israel Institute of Technology. Post-doctorate researcher Guilin Liu will soon become a professor at the University of Science and Technology of China. Recent doctoral graduate Carter Chamberlain, of Wrenthan, Massachusetts, will soon become a data scientist for private industry. Remaining in Blacksburg will be Department of Physics doctoral student Xinfeng Xu, of Guangde County, Anhui Province, China.
Xingfeng’s work on these projects will form his dissertation. “This is my first time working on the Hubble Space Telescope, and I am so lucky that we got three proposals at one time,” he said. “I am now following Dr. Arav and doing the relative research on active galactic nuclei (AGN) outflow. These nuclei have a black hole in its center, so it will be a very high-energy object. Many things about an AGN, like the structure and growth, are not fully understood. So I think it is a good starting point.”
Arav said he has been interested in space since he was 6 years old, when he watched news of the late 1960s moon landings by NASA and heard bedtime tall tales of science fiction adventures created by his father. Yet he knew he didn’t want to be an astronaut, even in second grade. He wanted others to bring space findings to him, so he could study and try to understand them. The Hubble Telescope is helping him do exactly that.