Category: Uncategorized

DIRECT-COLLAPSE BACK HOLES. “Given that overdense regions make up only 0.01%–0.1% of the Universe, the global number density of DCBH formation is predicted to be 10(-7) –10(-6) Mpc(-3) (co-moving), 100–1,000 times higher than previous estimates.” (DCBH = direct-collapse black holes). https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

BLACK HOLE FORMATION. “The morphology of the LWH is completely different from that of the MMH because of a recent major merger. The collision causes a sheet-like overdensity that cools to 300 K, becoming gravitationally unstable to fragmentation. A single clump fragments from the sheet and undergoes catastrophic collapse. All clumps in both target haloes have masses of around 10(3) Mʘ.” (Mʘ = solar mass; MMH = most massive halo; LWH = Lyman–Werner radiation flux). https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

MASSIVE BLACK HOLE FORMATION. “The Renaissance simulations show that the target haloes remain metal-free and are not exposed to any ionizing radiation. Their thermodynamic evolution and collapse are therefore primarily controlled by the growth history of the halo and the impinging LW flux. With these priors, we can safely neglect star formation and feedback, focusing on the dynamics of collapse.” (LH = Lyman–Werner). https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

EXTREME ENERGY. “The turbulent and thermal components act together to support the gas against collapse and create an effective sound speed.” https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

BIRTH OF BLACK HOLE. “As the core regions of both haloes start to undergo gravitational collapse, as outlined above, thermal, turbulent and rotational support will act to counteract the gravitational collapse.” https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

MOMENTS BEFORE GRAVITATIONAL COLLAPSE. “After reaching the atomic-cooling threshold, the gas begins to cool rapidly and (dynamical) heating mechanisms are suppressed. Above a temperature of approximately 8,000 K, radiative cooling of neutral hydrogen sets an upper limit for the temperature of the halo inside the virial radius, inducing a rapid increase in density and ultimately gravitational collapse.” https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

BLACK HOLE FORMATION. “Any halo that grows faster than this rate will have its gravitational potential deepen faster than it can collapse, making it more likely to support strong radial inflows, conducive for SMS formation.” (SMSs = supermassive stars). https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

BLACK HOLE PREDICTIONS. “In general, for dynamical heating to suppress metal-free star formation, halo growth must be rapid from the H2-cooling limit to the atomic-cooling limit. More specifically, it must happen faster than a free-fall time (20 Myr).” https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn