by Evan Schneider | Oct 3, 2012 | Daily Paper Summaries
We know most galaxies host supermassive black holes at their centers, but how do they get so big? In this study, the authors investigate one of the smallest known supermassive black holes (weighing in at only 100,000 solar masses), to shed some light on what a young, accreting black hole might look like.
by Nathan Goldbaum | Jun 16, 2012 | Daily Paper Summaries
One possible way to directly infer black hole properties is by observing the sort of event discussed in today’s paper: the tidal disruption of an individual star after a close approach to a supermassive black hole.
by Anna Rosen | Oct 9, 2012 | Daily Paper Summaries
In this article, the authors report their serendipitous discovery of two stellar mass-black holes in the globular cluster M22, however theoretical work predicts that there should only be one stellar-mass black hole!
by Evan Schneider | May 16, 2012 | Daily Paper Summaries
We know that supermassive black holes exist, but how did they get so big? In this paper, the authors seek to shed some light on their progenitors – rapidly accreting, intermediate-mass black holes.
by Lucia Morganti | Dec 16, 2011 | Daily Paper Summaries
Title: Two ten-billion-solar-mass black holes at the centres of giant elliptical galaxies Authors: Nicholas J. McConnell, Chung-Pei Ma, Karl Gebhardt, Shelley A. Wright, Jeremy D. Murphy, Tod R. Lauer, James R. Graham, Douglas O. Richstone First Author’s Institution: Department of Astronomy, University of California, BerkeleyThis Nature letter reports on a recent discovery that has also met with great interest in the popular press: astronomers have measured the biggest black holes ever! These two ten-billion-solar mass giants are significantly more massive than any other known black hole and more massive than predicted with the widely-used correlations relating the black hole mass to other properties of the host galaxy.First, a bit of context. Black holes are extremely compact concentrations of matter producing such strong gravitational pull that nothing, not even light, can escape. General relativity predicts such gravitational singularities of zero volume and thus infinite density. Studying stellar evolution, we learn that the explosions of heavy stars as supernovae can leave behind remnants of stellar mass-black holes. But super-sized black holes of million solar masses (called supermassive black holes) presumably originate from mergers of other black holes, or by accreting large amounts of stars and gas in an active galactic nuclei (AGN) phase.Nowadays astronomers believe that every galaxy harbours a supermassive black hole at its center, including our own Milky Way where a central mass concentration of four million solar masses has been deduced from 16-years monitoring of stellar proper motions (see also today’s astrobite on the amazing discovery of a huge gas cloud being swallowed by this black hole). As pointed out by Susanna’s astrobite, it is not possible to...
