Sgr A* – the supermassive black hole sitting in the center of the Milky Way – is often referred to as a ‘starved’ black hole, meaning that it swallows very little of the nearby cosmic gas and dust. The authors of this paper observed Sgr A* with the Chandra X-ray telescope for 3 mega seconds, throughout which only 1% of the gas available to Sgr A* actually accreted onto the black hole. It swallows cold gas, while rejecting hot gas – ejecting the matter back into space.
The long discussed gas cloud, G2, has finally begun its descent into the supermassive black hole at the center of our galaxy. The cloud has been so stretched that the head has swung around the black hole entirely and is rapidly coming back towards us (at a speed of 3000 km/s – 1% the speed of light), while the tail is still falling inwards – an event that will last for a year.
The gas cloud G2 is rapidly approaching the galactic center. Can tidal disruption events with stellar remnants help constrain its orbit?
TITLE: Supernovae in the Central Parsec: A Mechanism for Producing Spatially Anisotropic Hypervelocity Stars AUTHORS: Kastytis Zubovas, Graham A. Wynn, Alessia Gualandris AUTHORS’ INSTITUTION: Theoretical Astrophysics Group, University of Leicester Hypervelocity Stars In 2005, Brown et al. discovered a star with a radial velocity of ~700 km/s, which is more than 3 times the Solar […]
In this paper, the authors use near-IR imaging and spectroscopy to determine if G2, a galactic center source about to approach our galaxy’s supermassive black hole, is a gas cloud or a star.
Paper Title: Disruption of a Proto-Planetary Disk by the Black Hole at the Milky Way Centre Authors: Murray-Clay, R. A. and Loeb, A. Institution: Harvard-Smithsonian Center for Astrophysics (CfA) If our solar system lives in suburbia, the center of our galaxy is a sprawling metropolis shining bright for all to see. The center of our […]
As Astrobites reported a couple of months ago, the Fermi-LAT gamma-ray telescope has reported an anomalous peak at 130 GeV, which could be the long-sought annihilation signature of dark matter. However, one of the strongest critiques of this potential discovery is that the signal is not coming from Sgr A*, the dynamical center of the Milky Way, but rather from about 200 parsecs away. Kuhlen et al. challenge the idea that the dark matter peak must be located at the dynamical center, and find that the combined dark matter-baryonic matter simulation Eris shows a well-defined, consistent offset between its dark matter peak and dynamical center.
Five new hypervelocity stars have been discovered in the outer regions of the Milky Way. In this paper, the authors discuss what these stars are, how they got so far away, and what their distribution implies about the center of our galaxy.
The Center of our Galaxy is one of the most extreme dynamical environments we can observe in detail because individual stars can actually be resolved using adaptive optics. Over time, monitoring individual stellar orbits has firmly established the presence of a supermassive black hole of about 4 x 106 M☉ (check out this video too). Further examination of these fast-moving stars’ properties (via infrared spectroscopy) revealed a surprising detail — many of these stars are young!
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!