The DEVILS in the details: New research reveals how the cosmic landscape impacts the galaxy lifecycle

(Press-News.org) A team of astronomers from the International Centre for Radio Astronomy Research (ICRAR) has released new data from an extensive galaxy evolution survey that found a galaxy’s ‘neighbourhood’ plays a major role in how it changes over time.

The Deep Extragalactic Visible Legacy Survey, or DEVILS for short, has released its initial data and a series of recent publications explaining how a galaxy’s location in the Universe can significantly influence its evolution. The survey combines data from a wide range of international and space-based telescopes to investigate various aspects of astrophysics by analysing hundreds of thousands of galaxies. 

Project lead Associate Professor Luke Davies, from The University of Western Australia node of ICRAR, said the work represented the culmination of a decade’s worth of planning, observations and data analysis – offering a new level of detail in our understanding of galaxies in the distant Universe.  

The DEVILS survey is unique in that it is the first of its kind to explore the detailed aspects of the distant Universe. It focuses on galaxies that existed up to five billion years ago, and examines how these galaxies have changed to the present day. 

“While previous surveys during this period of Universal history have explored the broad evolution of galaxy properties, they have inherently lacked the capacity to determine the finer details of the cosmic landscape,” A/Professor Davies said.

“In the DEVILS survey, we have been able to zoom in and focus on mapping out the small-scale environment of galaxies – such as mountains, hills, valleys and plateaus as compared to large-scale environments such as oceans or continents.”

From this new approach, A/Professor Davies and his team have found that where a galaxy lives strongly influences its shape, size and growth rate in the distant Universe.        

This data will allow researchers to identify the number of stars in a galaxy, understand ongoing star formation, and analyse their visual appearance, shapes and structures. They can then compare these properties between galaxies in the present day Universe to galaxies that existed around five billion years ago and determine how galaxies are changing in time. 

“Our upbringing and environment influence who we are,” he said. “Someone who has lived their whole life in the city may have a very different personality compared to someone who lives remotely or in an isolated community. Galaxies are no different.” 

The team found that where a galaxy lived had a strong impact on many aspects of its lifecycle.

“Galaxies that are surrounded by lots of other galaxies - the bustling city centres of the cosmos – tend to grow more slowly and have very different structures compared to their isolated counterparts,” A/Professor Davies said.

In crowded regions of the Universe, galaxies interact with each other and compete for resources such as gas to form stars and grow. This competition can impact their evolution and, in some instances, cause star formation to slow down earlier than expected – causing galaxies to die. 

The DEVILS data continues to be utilised, and with this public release, the team expects other researchers to leverage the data for their own innovative research.

Associate Professor Davies’ team is now looking to expand the DEVILS survey.

“DEVILS forms the basis of our future plans in exploring this key area of astrophysics research,” he said.

“DEVILS has given us a detailed picture of galaxy evolution and next year, we will start collecting data for WAVES (Wide Area VISTA Extragalactic Survey). WAVES will allow us to significantly expand the number of galaxies and environments we study, plus help us build an even clearer picture of how the Universe came to look the way it does today”.

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