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Newly discovered most luminous galaxy

This artist's rendering shows a galaxy called W2246-0526, the most luminous galaxy known. New research suggests there is turbulent gas across its entirety, the first example of its kind. Image credit: NRAO/AUI/NSF; Dana Berry / SkyWorks; ALMA (ESO/NAOJ/NRAO)
Artist’s concept of galaxy W2246-0526, the most luminous galaxy known. New research suggests there’s turbulent gas across the whole galaxy, the first example of its kind. Image via NRAO/AUI/NSF; Dana Berry / SkyWorks; ALMA (ESO/NAOJ/NRAO)

Galaxy W2246-0526, 12.4 billion light-years from Earth, is now the most luminous galaxy known. It shines with the intensity of more than 300 trillion suns. A ravenous black hole at its center is devouring the galaxy and producing so much energy that it stirs up gas across the entire galaxy. That’s according to a new study published December 28, 2015 in The Astrophysical Journal Letters.

Tanio Diaz-Santos of the Universidad Diego Portales in Santiago, Chile, is lead author of the study. Diaz-Santos said in a statement:

It is like a pot of boiling water being heated up by a nuclear reactor in the center.

What does it mean to be the most luminous galaxy known? It means that, according to research published in 2015, galaxy W2246-0526 has the highest power output of any galaxy known so far in our universe.

If all galaxies were at the same distance from us, this galaxy would appear to shine most brightly.

The new study suggests that this galaxy is also expelling tremendously turbulent gas – a phenomenon never seen before in an object of this kind.

Roberto Assef, astronomer with the Universidad Diego Portales, is leader of the observing team at the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Assef said:

This galaxy is tearing itself apart. The momentum and energy of the particles of light deposited in the gas are so great that they are pushing the gas out in all directions.

According to the researchers, the growing supermassive black hole at the center of the galaxy is the likely engine of the turbulence. As the gravitational pull of the black hole attracts surrounding gas and other matter, the material forms a structure around it called an accretion disk.

The friction within this disk produces the intense brightness.

The black hole’s event horizon – the theoretical boundary beyond which no light or other radiation can escape – is thought to be one million times smaller than the W2246-0526 galaxy, yet the energy emitted by the black hole’s swallowing of material affects gas thousands of light-years away from it.

While turbulence has been detected in gas around supermassive black holes before – for example, around the centers of some nearby luminous galaxies that host active galactic nuclei – those winds are found to flow in specific directions.

This is the first time that highly turbulent gas has been found across the entire galaxy.

Researchers are unsure whether the gas is being pushed out strongly enough to leave the galaxy entirely, or if it will eventually fall back. Assef said:

A likely finale would be that the galaxy will blow out all of the gas and dust that is surrounding it, and we would see the accretion disk without its dust cover — what we call a quasar.

This galaxy is an example of a rare class of objects called Hot, Dust-Obscured Galaxies or Hot DOGs, which are powerful galaxies with supermassive black holes in their centers. Only 1 out of every 3,000 galaxies that WISE has observed is in this category.

Read more from NASA

Bottom line: New research published in late 2015 points to galaxy W2246-0526 as the current record-holder for most luminous galaxy known. It shines with the intensity of more than 300 trillion suns. Its central black hole produces so much energy that it stirs up gas across the entire galaxy. The galaxy is located in the early universe, 12.4 billion light-years from Earth.

January 18, 2016
Science Wire

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