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The formation of the first low-mass stars from gas with low carbon and oxygen abundances
It is shown that as soon as the primordial gas—left over from the Big Bang—is enriched by elements ejected from supernovae to a carbon or oxygen abundance as small as ∼0.01–0.1 per cent of that found in the Sun, cooling by singly ionized carbon or neutral oxygen can lead to the formation of low-mass stars by allowing cloud fragmentation to smaller clumps.
Jet-Launching Structure Resolved Near the Supermassive Black Hole in M87
Radio interferometry observations of the elliptical galaxy M87 are reported that spatially resolve the base of the jet in this source, suggesting that the M87 jet is powered by an accretion disk in a prograde orbit around a spinning black hole.
Formation of the First Supermassive Black Holes
We consider the physical conditions under which supermassive black holes could have formed inside the first galaxies. Our smoothed particle hydrodynamics simulations indicate that metal-free galaxies
Element Diffusion in the Solar Interior
We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multi-component fluid, including the residual
Discovering Planetary Systems through Gravitational Microlenses
Planetary systems of Galactic disk stars can be detected as microlenses of stars in the Galactic bulge. Planets in a solar-like system positioned half-way to the Galactic center should leave a
Self-regulated Growth of Supermassive Black Holes in Galaxies as the Origin of the Optical and X-Ray Luminosity Functions of Quasars
We postulate that supermassive black holes grow in the centers of galaxies until they unbind the galactic gas that feeds them. We show that the corresponding self-regulation condition yields a
Generic Spectrum and Ionization Efficiency of a Heavy Initial Mass Function for the First Stars
We calculate the generic spectral signature of an early population of massive stars at high redshifts. For metal-free stars with mass above 300 M☉, we find that the combined spectral luminosity per
Generation of Magnetic Fields in the Relativistic Shock of Gamma-Ray Burst Sources
We show that the relativistic two-stream instability can naturally generate strong magnetic fields with 10-5-10-1 of the equipartition energy density, in the collisionless shocks of gamma-ray burst
Birth of a relativistic outflow in the unusual γ-ray transient Swift J164449.3+573451
It is concluded that the tidal disruption of a star naturally explains the observed high-energy properties and radio luminosity and the inferred rate of such events, and the weaker beaming in the radio-frequency spectrum relative to γ-rays or X-rays suggests that radio searches may uncover similar events out to redshifts of z ≈ 6.