Every galaxy is thought to contain a black hole at the centre – but why are some active and some not? What process has ‘switched-on’ these active galaxies? Theorists suggest that major galaxy mergers could play a part for the highly luminous active galaxies but we’re currently lacking conclusive observational evidence to support this theory.
Short gamma-ray bursts, extremely energetic explosions in the Universe, might be caused by the merger of two compact objects. In the two papers we discuss today, the authors test this scenario by looking for light emitted still a few days after the explosion.
Do all tidal disruption events produce jets? This paper tests the hypothesis that they do!
Does the existence of mysterious, ultra-luminous X-ray sources indicate that black holes may become more massive than previously thought?
What happens when a neutron star collapses into a black hole? What kind of signal could we expect to see? These theorists have some ideas…
Small daily flares are observed from the black hole in the center of our galaxy. The authors of this paper propose the flares are due to Sgr A* frequently snacking on asteroids!
Remember that tidal disruption event we talked about earlier this year, where a star got just a little too close to a quiescent black hole? Well, here’s our chance to witness something similar, happening in the center of our very own galaxy!
Messier 87 (M87) is a giant elliptical galaxy that is best known for its spectacular, 5000-ly-long jet. In this paper, the authors develop models of M87 based on general relativistic numerical simulations and make predictions for the future direct observations of the black hole event horizon that may be possible.