Andromeda's Bling: Tiny Greedy Quasar Found
When we talk of quasars, we think: early universe; angry black holes in the centers of galaxies; gobs of energy; the ancient light of which is used today by astronomers to understand the primordial cosmos and the expansion of space-time. But what if I told you that astronomers have not only discovered a quasar in our modern Universe, but they’ve also discovered it right in our intergalactic back yard?
That’s right, the nearby spiral galaxy Andromeda is strutting some quasar bling.
But don’t go thinking Andromeda is having some galactic-sized delusions of grandeur, this particular quasar is a pipsqueak compared to the quasars of old. That said, microquasar XMMU J004243.6+412519 is something of a celebrity — it’s the first microquasar to be discovered beyond our own galaxy.
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Microquasars are, basically, stellar-mass black holes feasting on matter. Typically, these objects can be found consuming an unfortunate stellar sibling. The immense gravitational force of the black hole drags the neighboring star’s plasma into a superheated disk, generating intense X-rays. In the process of this star cannibalization, particles are also ejected at relativistic speeds from the black hole’s poles, radiating radio emissions. The result? A microquasar.
It is thought a similar process occurred for the earliest supermassive black holes residing in the middle of primordial galaxies, generating the vast powerhouses that characterized our early Universe. Therefore, the study of microquasars is very important to understand their supermassive cousins. However, as they are smaller, these tiny quasars fluctuate in energy — suggestive of changes in black hole “feeding rate” — something of great fascination for astrophysicists.
“This is, we think, the same mechanism at work in quasars at the cores of galaxies, where the black holes are millions of times more massive. However, in the smaller systems, things happen much more rapidly, giving us more data to help understand the physics at work,” said Matthew Middleton, of the University of Durham in the UK and the Astronomical Institute Anton Pannekoek, in Amsterdam, Netherlands, leader of the research team.
“Understanding how these things work is important, because we think quasars played a big role in redistributing matter and energy when the Universe was very young,” he added.
The discovery of XMMU J004243.6+412519 was originally made by the European XMM-Newton X-ray space observatory in January. NASA’s Swift and Chandra space telescopes then zoomed in on the object, observing it at gamma-ray and X-ray wavelengths respectively. The National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and Very Long Baseline Array (VLBA), plus the Arcminute Microkelvin Imager Large Array, studied the object at radio wavelengths. This multi-instrument campaign is helping astronomers glean an insight to the characteristics of the violent environment surrounding the estimated 10-solar mass stellar black hole.
The radio observations indicate the emissions are generated by a small volume of space, approximately the width of the distance of Jupiter from the sun. It also appears to generate similar emissions to other microquasars that have previously been discovered a little closer to home, in the Milky Way.
So Andromeda’s bling isn’t just for show, it’s an incredible opportunity to observe some fascinating black hole physics in a galaxy not-so-far away.
Image: The Andromeda galaxy, 2.5 million light-years away — plus location of the microquasar. Credit: Robert Gendler/NROA