A stunning set of photographs of nearby galaxies and an accompanying video, has been released by the European Southern Observatory (ESO). They were obtained by ESO's Very Large Telescope (VLT).
By combining these observations with data from their partner, the Atacama Large Millimeter/submillimeter Array (ALMA), they are shedding new light on the what triggers gas clouds to condense to form these galaxies, the details of which remain a mystery.
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. 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.
From the accompanying news release:
Eric Emsellem
Astronomer at ESO in Germany
Lead astronomer of the VLT-based observations
Physics at High Angular resolution in Nearby GalaxieS (PHANGS) project.
Astronomer at ESO in Germany
Lead astronomer of the VLT-based observations
Physics at High Angular resolution in Nearby GalaxieS (PHANGS) project.
Emsellem, who is also affiliated with the University of Lyon, France, and his team have now released their latest set of galactic scans, taken with the Multi-Unit Spectroscopic Explorer (MUSE) instrument on ESO’s VLT in the Atacama Desert in Chile. They used MUSE to trace 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.
The new MUSE images are now being combined with observations of the same galaxies taken with ALMA and released earlier this year. ALMA, which is also located in Chile, is especially well suited to mapping cold gas clouds — the parts of galaxies that provide the raw material out of which stars form.
By combining MUSE and ALMA images astronomers can examine the galactic regions where star formation is happening, compared to where it is expected to happen, so as to better understand what triggers, boosts or holds back the birth of new stars. The resulting images are stunning, offering a spectacularly colourful insight into stellar nurseries in our neighbouring galaxies.
There are many mysteries we want to unravel. Are stars more
often born in specific regions of their host galaxies — and, if so, why? And
after stars are born how does their evolution influence the formation of new
generations of stars?
Kathryn Kreckel
PHANGS team member
University of Heidelberg, Germany.
PHANGS team member
University of Heidelberg, Germany.
The new release continues:
Astronomers will now be able to answer these questions thanks to the wealth of MUSE and ALMA data the PHANGS team have obtained. MUSE collects spectra — the “bar codes” astronomers scan to unveil the properties and nature of cosmic objects — at every single location within its field of view, thus providing much richer information than traditional instruments. For the PHANGS project, MUSE observed 30 000 nebulae of warm gas and collected about 15 million spectra of different galactic regions. The ALMA observations, on the other hand, allowed astronomers to map around 100 000 cold-gas regions across 90 nearby galaxies, producing an unprecedentedly sharp atlas of stellar nurseries in the close Universe.
In addition to ALMA and MUSE, the PHANGS project also features observations from the NASA/ESA Hubble Space Telescope. The various observatories were selected to allow the team to scan our galactic neighbours at different wavelengths (visible, near-infrared and radio), with each wavelength range unveiling distinct parts of the observed galaxies.
“Their [different wavelengths] combination allows us to probe the various stages of stellar birth — from the formation of the
stellar nurseries to the onset of star formation itself and the final
destruction of the nurseries by the newly born stars — in more detail than is
possible with individual observations. PHANGS is the first time we
have been able to assemble such a complete view, taking images sharp enough to
see the individual clouds, stars, and nebulae that signify forming stars.
The work is continuing:
Francesco Belfiore
PHANGS team member
INAF-Arcetri in Florence, Italy.
PHANGS team member
INAF-Arcetri in Florence, Italy.
The work carried out by the PHANGS project will be further honed by upcoming telescopes and instruments, such as NASA’s James Webb Space Telescope. The data obtained in this way will lay further groundwork for observations with ESO’s future Extremely Large Telescope (ELT), which will start operating later this decade and will enable an even more detailed look at the structures of stellar nurseries.
As amazing as PHANGS is, the resolution of the maps that we produce is just
sufficient to identify and separate individual star-forming clouds, but not
good enough to see what’s happening inside them in detail. New observational efforts by our team and
others are pushing the boundary in this direction, so we have decades of
exciting discoveries ahead of us.
These pictures put me in mind of something Carl Sagan once said (an I paraphrase from memory):Eva Schinnerer
Principal investigator of the PHANGS project Research group leader at the Max Planck Institute for Astronomy, Germany.
Principal investigator of the PHANGS project Research group leader at the Max Planck Institute for Astronomy, Germany.
No preacher ever looked up at the Universe and said, "Wow! The Universe is much greater, more grand and much more impressive than our prophets ever told us!", instead, they say, "No! No! Ours is a small god and we insist it stays that way!"
The primitive Bronze Age hill farmers and Mesopotamian agriculturalists whose campfire tales got melded together and written down as the opening book of the Bible, could have known nothing of this vastness, of course. To them in their small, flat world in the centre of a small Universe, the sky was a dome with small lights fixed to it. A galaxy with maybe a trillion suns was reduced to a point of light, made by magic, while countless trillions more were too distant even to be seen.Consequently, to those who still believe this was an accurate description of reality, they assume this vastness was specially created by a magic man, so, in the outer arm of a very ordinary spiral galaxy, specifically with them in mind, so he could make a planet orbittng an otherwise unremarkable sun, for somewhere for them to live out their very special lives, and in the midst of this vastness, nothing is more important to this magic creature than how they live their lives, when and with whom they have sex and in what position they do it in, and whether they gather together regularly to shout incantations and sing songs to let it know how much they appreciate it. To these unfortunate people who get their science taught to them from a pulpit by people who know nothing about it either, the real magnificence of the Universe remains unknown and unappreciated.
As I said in the penultimate chapter of my basic science book, What Makes You So Special? From the Big Bang to You:
Your journey through space and time has been an adventure of disasters, adaptation, survival and recovery, many, many times you will have been on the brink of extinction - the fate of 99% of all known ancient species - yet your ancestors survived and because they were good at surviving you are here and now.
You will live for a mere flash in the time-scale of the Universe but in the vast darkness of the cosmos there can surely be few flashes as bright as your bright spark of consciousness.
Be proud. Be very proud. But at the same time be humbled by the enormity of the events which produced you and the fragility of it all.
Stars died and because they died, you live. You are made by stars out of stardust and in a very real sense; because you are made of the same stuff the Universe is made of and are a part of it, there is something even more wonderful about you. Through you, though not just through you, and maybe not just here on this small planet, the Universe has gained self–awareness and can begin to understand itself.
Through you it can stand on the surface of this beautiful little jewel in the cosmos, can look up in awe at itself and think "Wow!"
You are special. You are unique and you were nearly 14 billion years in the making.
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