FADO—a ground-breaking tool to reconstruct the history of galaxies

May 17, 2017
Image of the Triangulum Galaxy (M33) taken by the VLT Survey Telescope (VST), at ESO's Paranal Observatory. Even in this normal spiral galaxy, nebular emission (shown in red) provides locally an important fraction of the optical luminosity, especially in HII regions and spiral arms. Credit: ESO

FADO is a new analysis tool developed by Instituto de Astrofísica e Ciências do Espaço (IA) astronomers Jean Michel Gomes and Polychronis Papaderos, which uses light emitted by both stars and ionized gas in a galaxy to reconstruct its formation history by means of genetic algorithms. This tool was presented in a recent article, accepted for publication in the journal Astronomy & Astrophysics.

"Fado" derives from the Latin "Fatum," which means fate or destiny, and it's a tribute to Portugal's immaterial cultural heritage type of music of the same name. Each galaxy has a fado—a narrative of its biography since the birth of its first . This fate is written in its electromagnetic spectrum, which contains the fossil records of multiple stellar populations that formed over several billion years, as well as the gas that those stars ionize with their radiation.

Deciphering the of a galaxy from its spectrum is one of the most challenging tasks in astronomy. An innovative and distinctive feature of FADO is the use of genetic algorithms, which simulates galaxy evolution like the evolution of a living organism. It works by "breeding" multiple genetic threads for a galaxy, each defined by a set of parameters (similar to the genetic code in DNA), which evolve through exchange of "chromosomes," mutations and selection effects, until a population that matches the observed stars and gas emission of the galaxy is reached.

Jean Michel Gomes (IA & University of Porto) says, "FADO is the first spectral modeling code employing genetic differential evolution optimization in combination with artificial intelligence algorithms. This results in key improvements in computational efficiency and accuracy to which the star formation history of galaxies can be reconstructed."

Previous computer models developed for this purpose suffer from severe uncertainties, partly because they take into account only the light from stars. However, the contribution from ionized gas can add up to 50 percent of all emitted light in a galaxy.

Researcher Polychronis Papaderos says, "FADO is the first code of its type that simultaneously models stellar and ionized gas emissions in galaxies. It also integrates physical prescriptions which ensure that the star formation history computed for a galaxy consistently reproduces its observed emission. This presently unique self-consistency concept, in conjunction with the innovative mathematical foundation of FADO will allow us to gain new sharp insights into the galaxy formation history."

FADO's unique physical and mathematical concept yields great gain in computational efficiency, making the exploration of the star formation history of millions of an affordable task.

FADO will be an essential analysis tool to use with new generation instruments like MOONS, to be installed in the VLT (ESO). "MOONS is being constructed under the co-coordination of IA, and includes a substantial scientific and technical contribution from the Portuguese team. FADO will enhance tremendously our capability of exploiting the state-of-the-art observations MOONS will do from 2019 onwards," states the coordinator of IA, José Afonso.

Explore further: A new tool to study galaxy evolution

More information: J.M. Gomes et al. Fitting Analysis using Differential evolution Optimization (FADO): Spectral population synthesis through genetic optimization under self-consistency boundary conditions, Astronomy & Astrophysics (2017). DOI: 10.1051/0004-6361/201628986

Related Stories

A new tool to study galaxy evolution

February 1, 2017

RemoveYoung is a new tool developed by Instituto de Astrofísica e Ciências do Espaço (IA) astronomers Jean Michel Gomes and Polychronis Papaderos. It is designed to suppress the luminosity contribution of young stars from ...

VISTA peeks through the Small Magellanic Cloud's dusty veil

May 3, 2017

VISTA's infrared capabilities have now allowed astronomers to see the myriad of stars in the Small Magellanic Cloud galaxy much more clearly than ever before. The result is this record-breaking image—the biggest infrared ...

Hubble sees starbursts in Virgo

April 14, 2017

Although galaxy formation and evolution are still far from being fully understood, the conditions we see within certain galaxies—such as so-called starburst galaxies—can tell us a lot about how they have evolved over ...

A massive galaxy long ago and far away

February 6, 2017

Galaxies today fall roughly into two categories: elliptically-shaped collections of reddish, old stars that formed predominantly during a period early in the history of the universe, and spiral shaped objects dominated by ...

Recommended for you

Supermassive black holes feed on cosmic jellyfish

August 16, 2017

An Italian-led team of astronomers used the MUSE (Multi-Unit Spectroscopic Explorer) instrument on the Very Large Telescope (VLT) at ESO's Paranal Observatory in Chile to study how gas can be stripped from galaxies. They ...

Radio relic discovered in a low-mass merging galaxy cluster

August 16, 2017

Astronomers have detected a new single radio relic in a low-mass merging galaxy cluster known as PLCK G200.9−28.2. The finding, presented Aug. 5 in a paper published on the arXiv pre-print server, could offer some hints ...

NASA studies CubeSat mission to solve Venusian mystery

August 15, 2017

Venus looks bland and featureless in visible light, but change the filter to ultraviolet, and Earth's twin suddenly looks like a different planet. Dark and light areas stripe the sphere, indicating that something is absorbing ...

Team redefines cosmic velocity web

August 15, 2017

The cosmic web—the distribution of matter on the largest scales in the universe—has usually been defined through the distribution of galaxies. Now, a new study by a team of astronomers from France, Israel and Hawaii demonstrates ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

RNP
5 / 5 (3) May 17, 2017
An open access copy of the paper can be found here: https://arxiv.org...3922.pdf
cantdrive85
1 / 5 (5) May 17, 2017
The terrible irony is most, such as DNP, believe this pseudoscientific mumbo jumbo of "fado" and algorithms is some kind of science. As Barnum said, "a fool born every minute..."

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.