DEVILS is an extensive galaxy evolution survey that combines observations from multiple ground and space-based telescopes to analyse hundreds of thousands of galaxies. It focuses on systems seen as they were up to five billion years ago and tracks how their properties change to the present day.
Project lead Associate Professor Luke Davies from The University of Western Australia node of ICRAR described the DEVILS program as the result of about a decade of planning, observing and data processing to build a detailed picture of galaxies in the distant Universe. The survey is the first to probe small-scale structure in this era in comparable depth, going beyond earlier work that mainly traced broad changes in galaxy populations.
"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."
Using this approach, the team found that where a galaxy resides strongly affects its shape, size and growth rate. The new data set allows researchers to measure stellar mass, assess ongoing star formation, and study the visible structure and morphology of each system.
Scientists can now directly compare these properties between nearby galaxies and those that existed around five billion years ago to quantify how galaxies change over cosmic 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 reports that dense regions have a strong impact on many aspects of a galaxy's 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 environments, galaxies interact and compete for gas that fuels star formation and growth. This competition can alter their development and in some cases leads to an early shutdown of star formation, effectively causing galaxies to die sooner than they would in isolation.
The DEVILS data set is already in use by researchers and is now publicly available, opening the way for further independent studies of galaxy evolution. Associate Professor Davies and colleagues are preparing to extend this work with the Wide Area VISTA Extragalactic Survey, or WAVES.
"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".
Research Report:Deep Extragalactic VIsible Legacy Survey (DEVILS): First Data Release Covering The D10 (COSMOS) Region
Related Links
International Centre for Radio Astronomy Research
Stellar Chemistry, The Universe And All Within It
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