Stunning images of nearby galaxies revealing the locations of young stars as the gas warms up around them have been captured by astronomers.
The new observations resemble colourful cosmic fireworks, and were obtained with the European Southern Observatory's Very Large Telescope (VLT) in Chile.
Images show different components of the galaxies in distinct colours, allowing astronomers to pinpoint the locations of young stars and their surrounding gas.
Combining these observations with data from the ALMA telescope has allowed the team to shed new light on what triggers clouds of gas to go on to form stars.
Astronomers know that stars are born in clouds of gas, but what sets off star formation, and how galaxies as a whole play into it, remains a mystery.Insurance Loans Mortgage Attorney Credit Lawyer
They explored 30,000 nebulae of warm gas through 15 million spectra, and 100,000 cold-gas regions in 90 nearby galaxies to create a picture of star formation.
It is hoped this data will be able to be used by future teams of astronomers to learn more about how stars of all sizes are formed and use gas to grow.
This image combines observations of the nearby galaxies NGC 1300, NGC 1087, NGC 3627 (top, from left to right), NGC 4254 and NGC 4303 (bottom, from left to right) taken with the Multi-Unit Spectroscopic Explorer (MUSE) on ESO's Very Large Telescope (VLT)
Nearby galaxy NGC 1300, a spiral galaxy, with a bar of stars and gas at its centre, located approximately 61 million light-years from Earth in the constellation Eridanus is seen here
This image, taken by the Multi-Unit Spectroscopic Explorer (MUSE) on ESO's Very Large Telescope (VLT), shows the nearby galaxy NGC 4303. NGC 4303 is a spiral galaxy, with a bar of stars and gas at its centre, located approximately 55 million light-years from Earth in the constellation Virgo
Stars form from dense molecular clouds - of dust and gas - in regions of interstellar space known as stellar nurseries.
A single molecular cloud, which primarily contains hydrogen atoms, can be thousands of times the mass of the sun.Insurance Loans Mortgage Attorney Credit Lawyer
They undergo turbulent motion with the gas and dust moving over time, disturbing the atoms and molecules causing some regions to have more matter than other parts.
If enough gas and dust come together in one area then it begins to collapse under the weight of its own gravity.
As it begins to collapse it slowly gets hotter and expands outwards, taking in more of the surrounding gas and dust.
At this point, when the region is about 900 billion miles across, it becomes a pre-stellar core and the starting process of becoming a star.
Then, over the next 50,000 years this will contract 92 billion miles across to become the inner core of a star.
The excess material is ejected out towards the poles of the star and a disc of gas and dust is formed around the star, forming a proto-star.
This is matter is then either incorporated into the star or expelled out into a wider disc that will lead to the formation of planets, moons, comets and asteroids.
To understand this process, a team of researchers from the University of Heidelberg in Germany, with other ESO members, scanned galaxies for 'stellar births'.
'For the first time we are resolving individual units of star formation over a wide range of locations and environments in a sample that well represents the different types of galaxies,' says Eric Emsellem, an astronomer at ESO in Germany.
Emsellem is the lead of the VLT-based observations conducted as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) project.
'We can directly observe the gas that gives birth to stars, we see the young stars themselves, and we witness their evolution through various phases,' he said.
They traced newborn stars and the warm gas around them, which is illuminated and heated up by the stars and acts as a smoking gun of ongoing star formation.
Working with the ALMA telescope has helped get the finer detail, as this telescope 'is especially well suited to mapping cold gas clouds,' the team said.
These cold clouds are the parts of galaxies that provide the raw material out of which stars form.
By combining observations using the Multi-Unit Spectroscopic Explorer (MUSE) instrument on ESO's VLT, with ALMA images astronomers can examine the galactic regions where star