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HIERARCHICAL MODEL. “In this model, BHs evolve from light seeds (∼100 M⊙) and their growth is merger driven. The original Somerville et al. model (baseline model) reproduces the number density of AGN at intermediate redshifts and luminosities, but underproduces luminous AGN at very high redshift (z > 3) and overproduces them at low redshift (z < 1).” (BH = black hole; AGN = active galactic nuclei). https://lnkd.in/d9JV8md View in LinkedIn

GOALS. “We investigate whether this observed ‘downsizing’ in BH growth is reproduced in a semi-analytic model for the formation and evolution of galaxies and BHs, set within the hierarchical paradigm for structure formation.” (BH = black hole) https://lnkd.in/d9JV8md View in LinkedIn

COEVOLUTION OF LANGUAGE AND MATHS. “I will show in this essay that the origin of verbal language and mathematics depend on each other. We will explore the notion that mathematics is part of an evolutionary chain of six languages. One does not ordinarily think of computing and the Internet as languages but I will demonstrate that speech, writing, mathematics, science, computing and the Internet form an evolutionary chain of six languages.” https://lnkd.in/dq9dXxs View in LinkedIn

FRAGMENT FROM NATURE features for this and next weekend an excellent article by media ecologist and MIT-educated physicist Robert K. Logan, on the relationship between mathematics and language. His very original hypothesis runs counter to traditional thinking on the topic, and suggests that they are very intimately related in unexpected ways. https://lnkd.in/dKUCtJu View in LinkedIn

An extraordinarily flavorful and supremely ripe French cheese being prevented from galloping off the table. View in LinkedIn

CORRELATIONS. “All of these studies in the hard and soft X-ray range find that the cosmic evolution of AGN is strongly dependent on the AGN luminosity: the number density of successively less luminous AGN peaks at lower redshifts, with the lowest luminosity AGN showing a basically constant number density.” (AGN = active galactic nuclei). https://lnkd.in/d9JV8md View in LinkedIn

RARE BLACK HOLES. “More recently, it was discovered that very massive black holes (BH; 10(9) M⊙) appears to exist already at z ∼ 6 and higher, but they are extremely rare, in accordance with this trend.” (BH = black hole; z = redshift). https://lnkd.in/d9JV8md View in LinkedIn

THE CURVE. “It has been known since early optical quasar surveys that the comoving number density of luminous quasars has a pronounced peak at a redshift around z = 2–2.5, with a fairly steep decline at higher and lower redshift.” https://lnkd.in/d9JV8md View in LinkedIn

EXPLAINING THE HEAVENS. “Our best-fitting model suggests a scenario in which disc instabilities are the main driver for moderately luminous Seyfert galaxies at low redshift, while major mergers are the main trigger for luminous AGN.” (AGN = active galactic nuclei). https://lnkd.in/d9JV8md View in LinkedIn

EINSTEIN’S NEW WORLD ORDER. “The anti-intuitive properties of the special theory of relativity and its deep philosophical implications, the bizarre and dazzling predictions of the general theory of relativity: the curvature of spacetime, the exotic characteristics of black holes, the bewildering prospects of gravitational waves, the discovery of astronomical objects as quasers and pulsers, the expansion and the (possible) recontraction of the universe. . . are all breathtaking phenomena.” https://lnkd.in/dJ6fFGM View in LinkedIn