The Infamous Galactic Center Source G2: Gas Cloud or Star?
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.
No jets in the Galactic center?
Carretti and collaborators have found new evidence that the gigantic bubbles of emission emanating from the center of our Milky Way are the result of winds from supernova explosions, not jets from our supermassive black hole.
Sgr A*: A flickering black hole
Witzel et. al examine the statistical properties of the photometric variability of our Galaxy’s central black hole.
An Unlikely Planetary Nursery
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 Milky Way Galaxy is a crowded, bustling and hectic place. Stars race around like cars on a freeway. Densely-packed hot stars and supernova explosions flood the region with deadly radiation. The supermassive black hole at the center destroys anything that dares to wander too close and test its strength. The galactic center is different than what we’re used to. It’s exciting. It’s dangerous. It’s the kind of place that’s fun to visit, but you wouldn’t want to raise your kids there. The traditional wisdom among astronomers is that stars feel the same way; There is just too much excitement going on in the galactic center for planets to form around stars…Or is there?Last year, a team of astronomers at the Very Large Telescope (VLT) in Chile discovered a cloud of gas falling towards the black hole at the center, Sagittarius-A* (SgrA*). The team hypothesized that the gas cloud was the result of a collision between two gas clouds streaming from nearby stars. New research from the CfA proposes the seemingly-unlikely explanation the gas cloud is a proto-planetary disk surrounding a star that is too faint to see. A proto-planetary disk is a cloud of gas and dust that orbits a star for millions of years while it slowly coalesces into planets and asteroids and comets; It is where...
Forever feeding Sgr A*
Recent studies have revealed a surprising amount of activity happening in the heart of our own Milky Way. In this paper, Liu et al. explore the kinematics of the gas outside the most central regions of our galaxy, and reveal that the Galactic center is being fed even more material from the main structure of the Milky Way.
Star formation in the Galactic Center
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!