Astronomers find galaxy as bright as a quasar

Hyperaxion September 30, 2020 12:19 am

Researchers have found that the rate of star formation in the BOSS-EUVLG1 galaxy is about a thousand times higher than in the Milky Way, although the galaxy is 30 times smaller.

Scientists at the Centre for Astrobiology and the Instituto de Astrofísica de Canarias (IAC) have discovered a new galaxy, called BOSS-EUVLG1, whose ultraviolet luminosity is comparable to that of a quasar, the brightest object in the Universe.

The finding will be published in the Monthly Notices of the Royal Astronomical Society Letters, but a preprint version is available on ArXiv.

BOSS-EUVLG1 has a redshift of 2.47, a rate that can be used to find its distance from Earth – the higher the value, the further away it is.

In the case of the new galaxy, astronomers found that it was observed when it was approximately 2 billion years old, about 20% of its current age.

The galaxy is so bright that researchers initially thought it was a quasar.

However, after carefully analyzing the data, the team realized that the high ultraviolet and Lyman-alpha luminosity is due to the high number of young and massive stars in BOSS-EUVLG1, in addition to little dust and very low metallicity.

The rate of star formation in this galaxy is very high, around a thousand solar masses per year, about a thousand times higher than in the Milky Way, although the galaxy is 30 times smaller in size.

“This rate of star formation is comparable only to the most luminous infrared galaxies known,” explained co-author Ismael Pérez Fournon, an IAC researcher.

“But the absence of dust in BOSS-EUVLG1 allows its ultraviolet and visible emission to reach us with hardly any attenuation.”

The results of the study suggest that BOSS-EUVLG1 is an example of the early stages of the formation of massive galaxies.

This is because, despite the high luminosity and rate of star formation, the low metallicity indicates that the galaxy did not have time to enrich its interstellar medium with dust and metals.

According to the scientists, the galaxy will evolve into a more dusty phase, similar to galaxies detectable by infrared radiation.

Also, its high luminosity in the ultraviolet spectrum will only last a few hundred million years, a very short period, cosmologically speaking.

“This would explain why other galaxies similar to BOSS-EUVLG1 have not been discovered,” said co-author Claudio Dalla Vecchia, who also works at the IAC.


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