Triangulum Galaxy

UV space telescope to study the space between galaxies

Image credit: pa

A space telescope barely larger than a mini fridge could reveal new secrets about the cosmos, thanks to onboard instruments which observe the ultraviolet spectrum.

The Aspera mission, which will receive around $20m in funding from Nasa, is designed to study the evolution of galaxies and the spaces between them. In particular, the mission seeks to solve a longstanding mystery about the way galaxies form, evolve and interact with each other.

Intended for launch in late 2024, the space telescope is being specifically designed to see in ultraviolet light, which is invisible to the human eye.

The Aspera mission’s goal is to provide the first-ever direct observations of specific portions of the universe known as the circumgalactic medium (CGM). The CGM comprises the areas containing low-density gas that surround individual galaxies and in some cases connect them, bridging large distances across the universe.

“As telescopes have become more sensitive and have allowed us to discover more exotic types of gases, we now realize there is tons of stuff in between galaxies that connects them,” said principal investigator Dr Carlos Vargas, an expect in galactic evolution at the University of Arizona. “Galaxies are undergoing this beautiful dance in which inflowing and outflowing gases balance each other.”

Processes such as supernova explosions blow gas out of the galaxy, and sometimes it rains back down onto the galactic disc, he said.

Previous observations of the CGM revealed that it contains several different populations of gas in a wide range of densities and temperatures astronomers refer to as phases. One of these gas phases has eluded previous attempts at studying it but is important because it is believed to host most of a galaxy’s mass.

“There is this intermediate form we refer to as warm-hot, and that is particularly interesting because it provides the fuel for star formation,” Vargas said. “No one has been able to successfully map its distribution and really determine what it looks like.”

The Aspera mission is designed to home in on that missing chunk of the CGM that astronomers know must be there but haven’t been able to observe.

“Though small, Aspera is designed to detect and map faint warm-hot gas, thanks to recent technological advancements and the increased opportunity that small-sized space missions provide,” said Dr Haeun Chung, a  research associate at Steward Observatory.

The Aspera telescope will be the only instrument in space capable of observing in the ultraviolet spectrum, with the exception of the Hubble Space Telescope, which has surpassed its expected mission lifespan by many years.

In November, the European Space Agency approved plans to build the world’s first space telescope dedicated to studying the atmosphere of exoplanets.

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