Astronomers find the first galaxy whose ultraviolet brightness is compared to a quasar


Astronomers find the first galaxy whose ultraviolet brightness is compared to a quasar

Left and center: Image of the boss’ area containing the BOSS-EUVLG1, which stands out due to its blue color. Credit: Desi Legacy Imaging Survey. Right: Artist’s drawing of a burst of star formation in BOSS-EUVLG1, which includes a large number of young big stars, and hardly any dust. Credit: Gabriel Perez Deese, SMM (IAC).

Using observations made with the Gran Telescopio Canarias (GTC) at the Roque de los Muchachos Observatory (Garafía, La Palma, Canary Islands), and with the ATACAMA Large Perimeter / Submillimeter Array (ALMA), in Chile, astronomers first reported Have got. The galaxy whose ultraviolet brightness is compared to that of a quasar. This discovery was recently published in the journal Monthly notifications of Royal Astronomical Society letters.


This galaxy named BOSS-EUVLG1 has a red-shift of 2.47. It is a measure of the light coming from the galaxy to be red, and can be used to find its distance: the farther the galaxy is, the higher the value. For BOSS-EUVLG1, a value of 2.47 means that when the universe was about 2000 million years old, about 20% of its present age has been observed by the Milky Way.

The large redshift and luminosity values ​​of BOSS-EUVLG1 pre-classified it as a quasar in the BOSS (Berian Oscillation Spectroscopic Survey) project. However, from observations made on the GTC with OSIRIS and EMIR devices and the millimeter-wave telescope ALMA, researchers have shown that it is not a quasar, but is actually a galaxy with extreme, extraordinary properties.

The study showed that the high brightness of BOSS-EUVLG1 in ultraviolet and in Lyman-alpha emission is due to the large number of young, massive stars in the galaxy. Over the range of other galaxies, this high luminosity led to its initial recognition as a quasar. However, in quasars, the high luminosity is due to the activity around the supermassive black hole in their nucleus, not to form a star.

“Boss-EUVLG1 appears to dominate the bursting of young, very massive stars, with hardly any dust, and very little metal,” Rui Marks Chews, a researcher at CAB, formerly A doctoral student explains. Instituto de Astrofísica de Canarias and University of La Laguna (ULL), and the first author of the article.

This galaxy has a very high star formation rate, about 1000 solar masses per year, which is about 1000 times larger than the Milky Way, although the galaxy is 30 times smaller. “This rate of star formation is comparable only to the brightest infrared galaxies,” explains IAS researcher and Damel Perrys Foran, but the absence of dust in BOSS-EUVLG1 reaches us with hardly any attenuation of its ultraviolet and visible emission. She gives. “Co-author of the article.

The study results suggest that BOSS-EUVLG1 is an example of the early stages of the formation of large-scale galaxies. Despite its high luminosity and star-making rate, its low metallicity suggests that the galaxy does not have time to enrich its interstellar medium with dust and newly formed metals. Nevertheless, IAC doctoral student and co-author Camilo E. Jiménez, ngel states, “The galaxy will evolve toward a dustier phase similar to infrared galaxies. Furthermore, its high brightness in UV will be only a few hundred million years, a . Very short time in the evolution of the Milky Way. ”

“This will explain why other galaxies similar to BOSS-EUVLG1 have not been discovered,” says Claudio Dalla Vecchia, researcher at the IAC and co-author of the article.

BOSS-EUVLG1 was discovered in the Sloan Digital Sky Survey (SDSS) BOSS project through analysis of half a million spectra of galaxies and quasars and observations with large telescopes such as GTC and ALMA.


SDSS J2310 + 1855 interstellar medium discovered with ALMA


more information:
Discovery of the most UV-ly-alpha luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosity. Arxiv: arxiv.org/abs/2009.02177v1

Provided by Instituto de Astrofísica de Canarias

Quotes: Astronomers find the first galaxy whose ultraviolet luminosity is higher than that of a quasar (2020, 28 September) from https://phys.org/news/2020-09-astronomers-galaxy-ultraviolet-luminosity-quasar on 29 September 2020 Is obtained. .html

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