Today’s Picture of the Week gives us a closer look at how black holes
in the centre of galaxies feast. As some of you already know, the
common belief that black holes simply suck in anything that comes near
them, is wrong. Material can only fall into a black hole when it’s slowed down somehow — so what's pumping the brakes?
To answer this question, a team of astronomers led by Wout Goesaert, now a PhD candidate at Leiden University, the Netherlands, mapped how molecular gas is distributed in the Circinus galaxy, about 13 million light-years away. The galaxy is shown in the top left corner in visible light. The two insets are images taken with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner. Gas is streaming towards the black hole through two spiral arms that are embedded in the disc, seen in the innermost regions of the top-right picture. These arms feed the doughnut-shaped cloud around the black hole seen at the bottom.
The gravitational influence of the spiral arms perturbs the motion of the molecular gas, which falls right into the monster's mouth, the same way a satellite would fall onto Earth if its orbit was disturbed. The feeding process is very inefficient though: the team found that about 90% of the material does not end up in the black hole but is rather spat back out, like a massive toddler refusing to eat.
To answer this question, a team of astronomers led by Wout Goesaert, now a PhD candidate at Leiden University, the Netherlands, mapped how molecular gas is distributed in the Circinus galaxy, about 13 million light-years away. The galaxy is shown in the top left corner in visible light. The two insets are images taken with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner. Gas is streaming towards the black hole through two spiral arms that are embedded in the disc, seen in the innermost regions of the top-right picture. These arms feed the doughnut-shaped cloud around the black hole seen at the bottom.
The gravitational influence of the spiral arms perturbs the motion of the molecular gas, which falls right into the monster's mouth, the same way a satellite would fall onto Earth if its orbit was disturbed. The feeding process is very inefficient though: the team found that about 90% of the material does not end up in the black hole but is rather spat back out, like a massive toddler refusing to eat.
Links
- Research paper accepted for publication in Astronomy & Astrophysics
- Press release at the Netherlands Research School for Astronomy
Source: ESO/potw
