The black hole at the center of our galaxy, Sgr A*, is a very picky eater. However, with the discovery of the G2 cloud, astronomers have had the opportunity to watch the infrequent feeding process in Sgr A* in action. While the origin of this cloud is still debated, research is beginning to suggest that G2 is a gas cloud that was ripped away from a giant star in orbit around our galaxy’s central black hole.
How do simulations of galaxy formation stack up against each other and against observations? Find out with the Aquila project, a comparo of many different codes in current use.
Has a multi-wavelength study of AGN across a large redshift range revealed that these energetic giants do not impact upon their host galaxy as significantly as previously thought?
The progenitors of a special type of cataclysmic variable, AM CVn, and possibly supernovae have been found.
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.
Maksym et al. investigate a possible tidal flare event in Abell 1795.
The formation of massive stars is still an intense topic of debate. Observations are difficult because massive star forming regions are heavily obscured by dust – invisible in the optical and near infrared. The trick is to look at much longer wavelengths. Today’s paper does just that, using the Atacama Large Millimeter Array (ALMA) in Chile to observe the birth of a massive star in submillimeter wavelengths. At 500 times the mass of the Sun and 1 million times brighter, it is the largest forming protostar ever seen in our galaxy.
The authors of today’s paper investigate the feeding habits of the elusive quiescent supermassive black hole, finding that in addition to swallowing some stars whole and constantly snacking on the winds of other stars, some black holes may also dine on giant stars slowly disrupted over tens to hundreds of orbits.
There’s a lot going on in the HD 142527 protoplanetary disk — accretion, gap opening, and a horseshoe-shaped dust ring. The authors of this paper used ALMA to take a closer look at the gas and dust in this busy disk.
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.