A black hole of more than four million solar masses hides at the center of our Galaxy, but it is rather idle nowadays.

However, in 2010, the space observatory Fermi found two gigantic gas "bubbles" giving off very high-energy gamma rays centered on that area. These structures, high of 25.000 light years, are perpendicular to the galactic plane and arranged on both sides of it.

To learn more about this supermassive black hole, researchers made a large-scale map of the X emission of the heart of our galaxy. This map covers an 1800 x 1500 light years region and gathers observations made from 2016 to 2018 with XMN-Newton, as well as data previously recorded by this satellite.

This spectacular picture shows two "chimneys" full of gas heated to several millions degrees. These cylindrical structures grew on both sides of the galactic plane to almost 500 light years, precisely aligned with the Fermi Bubbles.

According to Andrea Goldwum, an Irfu researcher, "the most convincing hypothesis is that those chimneys carry energy from the most active region at the heart of the Galaxy to the outside, therefore fueling the Fermi Bubbles, as their morphology suggests"

However, there is no strictly established link between the chimneys and the supermassive black hole. Since the heart of the galaxy contains a large number of stars, it is not impossible that exploding stars (supernovae) or particles winds from massive stars are responsible for fueling the chimneys.

Nevertheless, the link between the chimneys and the Fermi Bubbles indicates a very intense activity at the center of our Galaxy, only a few million years old. The black hole is closely watched more than ever!

                                         Low-energy X-ray image of the galaxy's central region, achieved thanks to XMN-Newton's data (G. Ponti et al. 2019, Nature, issue of March 21, 2019). ©NASA/DOE/Fermi Gamma-Ray Space Telescope/LAT detector/D.Finkbeiner et al.

This research was conduct in collaboration with the laboratory "AstroParticule et Cosmologie" of Paris and the Astrophysics and Planetology Institute of Grenoble, with the support of the Centre National d'Etudes Spatiales.