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A new University of Leicester study shows how the uncontrolled growth of a distant supermassive black hole (SMBH) is revealed by the ejection of excess matter as a high velocity wind.

in Monthly Notices of the Royal Astronomical Society, it describes for the first time how the black hole's "overeating" of new matter led to the excess being ejected at nearly one-third of the speed of light.

Powerful outflows of ionized gas have been a major interest of ESA's XMM-Newton X-ray Observatory since first detected by Leicester X-ray astronomers in 2001, and subsequently recognized as a characteristic feature of luminous AGN.

A black hole is formed when a quantity of matter is confined in a sufficiently small region that its gravitational pull is so strong that nothing—not even light—can escape. The size of a black hole scales with its mass, being 3km in radius for a solar mass hole.

¸é±ð²¹±ô—a²õ³Ù°ù´Ç±è³ó²â²õ¾±³¦²¹±ô—black holes of stellar mass are common throughout the galaxy, often resulting from the violent collapse of a massive star, while a supermassive black hole (SMBH) may lurk in the nucleus of all but the smallest external galaxies.

University of Leicester scientists conducted a 5-week study of an SMBH in the distant Seyfert galaxy PG1211+143 in 2014, about 1.2 billion light years away, using the ESA's XMM-Newton Observatory, finding a counter-intuitive inflow that added at least 10 Earth masses to the black hole's vicinity (MN 2018), with a ring of matter accumulating around the black hole being subsequently identified by its gravitational redshift ().

The final part of this story now reports a powerful new outflow at 0.27 times the speed of light, launched a few days later, as gravitational energy released as the ring is drawn towards the hole heats the matter to several million degrees, with radiation pressure driving off any excess.

Professor Ken Pounds from the University of Leicester School of Â鶹ÒùÔºics and Astronomy, lead author of the three papers, commented, "Establishing the direct causal link between massive, transient inflow and the resulting outflow offers the fascinating prospect of watching an SMBH grow by regular monitoring of the hot, relativistic winds associated with the accretion of new matter."

PG1211+143 was a target of University of Leicester X-ray astronomers, using the ESA's XMM-Newton Observatory, from its launch in December 1999. An early surprise was detecting a fast-moving, counter-intuitive outflow, with a velocity 15% of light (0.15c), and the power to disrupt star formation (and hence growth) in the host galaxy. Later observations found such winds to be a common property of luminous AGN.

The availability of simultaneous ultraviolet fluxes from the Neil Gehrels Swift Observatory, a NASA mission which Leicester hosts the UK Swift Science Data Center for, was—and will remain—critical in understanding the accretion process in SMBH.