Month: September 2022

SUPERMASSIVE STARS. “SMSs and therefore DCBHs that form in rapidly growing haloes, as proposed here, will be tens of kiloparsecs away from the large-scale overdensity. They will take hundreds of millions of years—a substantial fraction of the age of the Universe at z > 6—to fall into the nearby group of galaxies.” DCBH = direct-collapse black holes; SMSs = supermassive stars). https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

OBSERVATIONS. “We predict that these DCBHs will evolve to form the population of faint quasars observed at z ≈ 6. This population will be within the reach of the James Webb Space Telescope, which will be able to provide stringent constraints on their number densities that will be directly comparable to our results.” (DCBH = direct-collapse black holes). https://www.nature.com/articles/s41586-019-0873-4 View in LinkedIn

COMPLETED MODEL. “We are confident that our simulation follows the complete star-formation history of all collapsed structure, and thus the metal-enrichment history of pre-galactic gas that is vital to determining the conditions for DCBH formation.” (DCBH = direct-collapse black holes). 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

BLACK HOLE MODEL. “At these scales, the gas density dominates the matter density, and by smoothing the dark-matter density we remove any artefacts associated with the discrete representation of the dark-matter mass distribution.” 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

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

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