Researchers of the Atacama Large Millimeter/submillimeter Array (ALMA) observatory captured this black hole in action, as this process is known as accretion, which is a method where black holes collect more mass, appearing to snack on some cold cosmic gas clouds.
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Illustration credit: NRAO/AUI/NSF; Dana Berry/SkyWorks; ALMA (ESO/NAOJ/NRAO).An worldwide team of astronomers using the Atacama Large Millimetre/submillimetre Array (ALMA) has witnessed a cosmic weather event that has never been seen before – a cluster of towering intergalactic gas clouds raining in on the supermassive black hole at the centre of a huge galaxy one billion light-years from Earth.
Using ALMA, the study team looked into a highly luminous cluster of around 50 galaxies, collectively referred to as Abell 2597.
McDonald says these three cold gas clouds will likely not stream straight into the black hole but instead be absorbed into its accretion disc – the massive disc of material that will eventually spiral into the black hole. Each cloud contains as much material as a million Suns and is tens of light-years across. They are now speeding toward the black hole at almost a million kilometers per hour. Tremblay et al./NASA/ESA Hubble/ALMA (ESO/NAOJ/NRAO).”This very, very hot gas can quickly cool, condense, and precipitate in much the same way that warm, humid air in Earth’s atmosphere can spawn rain clouds and precipitation”, Tremblay said.
The scientists directly observed a clumpy rain of cold molecular gas clouds moving toward the core of the Abell 2597 Brightest Cluster Galaxy at about 671,000 miles per hour (1 million km/h).
“The newly condensed clouds then rain in on the galaxy, fueling star formation and feeding its supermassive black hole”.
Astronomers used to think that supermassive black holes – especially in the largest galaxies – had diets that consisted primarily of ionized gas from the galaxy’s halo. Recently, however, theoreticians have started to believe that in addition to this gradual feeding, these objects can also devour whole clouds of cold gas in one sitting.
Scientists have directly observed a supermassive black hole feeding for the first time – and they learned it isn’t eating the kind of meal that they had assumed.
“I$3 f the clouds really are that close to the black hole, we should see them physically move on human timescales – that is, six months to a few years”, Tremblay told Charles Q. Choi at Space.com. “It’s sort of been there all along, and now we just now are realizing that it’s falling into the black hole and providing the energy for the activity that we see”. It turns out that something similar happens among clusters of galaxies characteristically found commingling with clouds of hot, ionized plasma-some regions of gas cool and fall inward as they condense.
The results have been described in Nature.
This causes sporadic rainstorms with droplets of cold gas, and for a short amount of time, the black hole “eats” quickly.
The carbon monoxide in the clouds cast characteristic “shadows” of certain colours in the presence of the bright light from the black hole, allowing the carbon monoxide to be detected, Tremblay said.
The global team of scientists looked at an unusually bright cluster of galaxies, the most massive of which is an elliptical galaxy called the Abell 2597 Brightest Cluster Galaxy.
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“We got very lucky”, claimed Michael McDonald, assistant professor of physics in MIT’s Kavli Institute for Astrophysics and Space Research, in a statement. We know from previous work that the black hole in this object is now devouring material, so it seemed like an excellent place to look if we wanted to find out what it had on the menu.
