Galactic fireworks: stunning features of nearby galaxies revealed
Cosmic fireworks reveal new born stars.
Video by the European Southern Observatory
Breathtaking images of galaxies close to the Milky Way have been released by an international team of astronomers exploring the mystery of how stars are born.
The amazing images, observed using telescopes operated by the in Chile鈥檚 Atacama Desert, show different components of the galaxies in distinct colours, allowing astronomers to pinpoint the locations of young stars and the gas they warm up around them. These stellar nurseries hold the secrets of how clouds of cold gas ignite to become stars.
To non-astronomers, the galaxies look like captured images of a beautiful fireworks display.
Dr Rebecca McElroy from the at the University of Sydney is part of the international research team.
Dr Rebecca McElroy.
鈥淏y combining observations from some of the world鈥檚 most powerful telescopes, we can examine the galactic regions where star formation is happening, compared to where it is expected to happen,鈥� she said.
鈥淭his will give us a chance to better understand what triggers, boosts or holds back the birth of new stars,鈥� she said.
Astronomers know that stars are born in clouds of gas, but what sets off their formation 鈥� and what role galaxies play in this 鈥� remains a mystery. To better understand this process, more than 90 scientists from 30 institutions around the world are observing nearby galaxies using powerful ground and space-based telescopes.
The work is part of the聽聽(Physics at High Angular Resolution in Nearby GalaxieS) survey, which includes ESO鈥檚 Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA).
ALMA combines radio wavelength signals from 66 dish-shaped antennas, while the VLT consists of four large 8-metre telescopes and four smaller telescopes that can be used separately or combined into a single larger instrument.
Five observed galaxies within 80 million light years of Earth. Credit: ESO/PHANGS
A high-tech instrument attached to the Very Large Telescope called the聽, was used for the recent observations.
MUSE collects spectra 鈥� the 鈥渂ar codes鈥� of light that astronomers scan to unveil the properties and nature of cosmic objects 鈥� at every single location within its field of view, providing much richer information than traditional instruments. For the PHANGS project, MUSE observed 30,000 clouds of warm gas and collected about 15 million spectra of different galactic regions.
鈥淢USE has given us an unprecedented view of what鈥檚 going on inside galaxies,鈥� said聽, a PHANGS team member from the University of Western Australia node of the International Centre for Radio Astronomy Research ().
The ALMA observations allowed astronomers to map about 100,000 cold-gas regions across 90 nearby galaxies, producing an unprecedentedly sharp聽聽in the close Universe. They include galaxies such as Messier 100, about 55 million light years from Earth, considered nearby in galactic terms.
鈥淏y combining these observations with those from ALMA, we鈥檙e able to see newborn stars while they鈥檙e still surrounded by the blanket of gas they鈥檝e formed from,鈥� Dr Groves said.
鈥淭he resulting images are absolutely stunning 鈥� they allow us a spectacularly colourful insight into the stellar nurseries of our neighbouring galaxies.鈥�
In addition to ALMA and MUSE, the PHANGS project features observations from NASA鈥檚聽. The various observatories were selected to allow the team to scan our galactic neighbours at different wavelengths (visible, near-infrared and sub-millimetre), with each wavelength range unveiling the distinct processes that occur across the observed galaxies.
The work carried out by the PHANGS project will be further developed by upcoming telescopes and instruments, such as NASA鈥檚聽. The data obtained will lay further groundwork for observations with ESO鈥檚 future Extremely Large Telescope (ELT), which will start operating later this decade. This telescope will enable an even more detailed look at the structures of stellar nurseries.
Five galaxies observed by PHANGS
European Southern Observatory
The European Southern Observatory is an astronomy organisation with 16 member states, along with the host country of Chile and Australia as a strategic partner. It plays a leading role in promoting and organising international research cooperation and provides state-of-the-art research facilities to astronomers.
In 2017 the Australian Government entered into a 10-year strategic partnership with ESO, as a pathway to potential full membership at the end of this period.
This unique partnership is giving Australian astronomers access to the world鈥檚 most advanced聽, enabling research at the leading-edge of discovery.
Declaration
Dr Brent Groves is a researcher for the聽聽鈥� a joint venture between Curtin University and the University of Western Australia with support and funding from the State Government of Western Australia. Dr Rebecca McElroy works on projects with聽Professor Scott Croom聽at the University of Sydney funded by an Australian Research Council Discovery Project.