Some of the most luminous objects in the Universe are the jets produced by the supermassive black holes that reside at the center of nearly all galaxies. These jets use the energy from particles that have fallen into the black hole's accretion disk and rocket some of that matter out at nearly light speed. As these particles shed energy by emitting photons, they turn the jet into a fantastically bright object.

Studying these jets, however, is a real challenge, because most of them occur in galaxies far from our own. Since we've identified a supermassive black hole at the center of our own galaxy (Sgr A*), the obvious solution would be to study that. But that's been easier said than done. As the authors of a new study put it, "despite its virtue of proximity," the center of our own galaxy is a busy place, with lots of energetic objects. Unfortunately, the matter trapped by the black hole isn't one of them; the same authors describe the Milky Way's central black hole as "exceptionally underluminous."

As a result, astronomers have announced the discovery of jets from Sgr A* a total of seven times; most of these supposed jets don't point in the same direction, suggesting the majority of them are wrong. But an analysis of a huge trove of X-ray data from the Chandra Observatory, coupled with some observations in the infrared, have led a team of researchers to give the nod to one of the candidates: an X-ray feature with the catchy name G359.944-0.052.

G359.944-0.052 had been seen before and had even been suggested as a possible indication of a black hole jet. But the team behind the current research has gone back and gathered over 1.4 million seconds of observation time from the Chandra to get a clearer picture of the feature, shown below. The center of the galaxy is lit with X-ray sources (purple), but G359.944-0.052 stands out for a number of reasons. To begin with, it's linear. And, if you follow the line back toward the galaxy's center, it points pretty directly to Sgr A*. It also lines up nicely with the galaxy's axis of rotation.

(The accretion disk won't necessarily line up with the rotation of the galaxy, but there are a number of reasons why it might be likely for it to do so.)

The infrared activity at our galaxy's center (in blue above) is almost as complicated as the X-ray picture. But if you trace G359.944-0.052 back toward the galactic center, the point where it intercepts the infrared emitting material contains a very bright, chevron-shaped object. This, the paper concludes, can be interpreted as a shock front, where the particles of the jet slam into some dense gas.

A look back in time suggests that G359.944-0.052 has been a constant feature for at least a decade. It's also a rather large feature; the authors refer to it as "parsec scale" (a parsec is a bit over three light years).

The authors spend some time considering an alternative explanation, one that involves a supernova remnant lit up by a pulsar within it. But none of the examples of these objects that we've observed in the galactic core show the sort of properties that G359.944-0.052 has. So, the authors are pretty sure they've finally located the jet from our galaxy's black hole.

The arXiv. Abstract number: 1310.0146 (About the arXiv). To be published in The Astrophysical Journal.