Quasars tagged posts

This is an artist’s concept of the metric expansion of space, where space (including hypothetical non-observable portions of the universe) is represented at each time by the circular sections. Note on the left the dramatic expansion (not to scale) occurring in the inflationary epoch, and at the center the expansion acceleration. The scheme is decorated with WMAP images on the left and with the representation of stars at the appropriate level of development. Credit: NASA

Scientists have created computer simulations of events soon after the Big Bang to better understand how stars today are being formed. Researchers have formed the clearest picture yet of massive explosions that controlled the creation of galaxies, including our own, and continue to influence star formation today...

This schematic representation illustrates the technique used to probe the small-scale structure of the cosmic web using light from a rare quasar pair.
Credit: J. Onorbe / MPIA

A team of astronomers have made the first measurements of small-scale ripples in this primeval hydrogen gas using rare double quasars. Although the regions of cosmic web they studied lie nearly 11 billion light years away, they were able to measure variations in its structure on scales 100,000 times smaller, comparable to the size of a single galaxy.

Intergalactic gas is so tenuous that it emits no light of its own. Instead astronomers study it indirectly by observing how it selectively absorbs the light coming from faraway sources known as quasars...

In an artist’s conception, heated galactic wind shown in the hazy portion of the picture emanates from the bright quasar at the edge of a black hole, scattering dust and gas. If allowed to cool and condense, that dust and gas would instead begin to form stars. Credit: Johns Hopkins University

Quasars slowed star formation new research shows. It appears intense radiation and galaxy-scale winds emitted by the quasars – the most luminous objects in the universe – heats up clouds of dust and gas. The heat prevents that material from cooling and forming more dense clouds, and eventually stars.

They looked at information on 17,468 galaxies and found a tracer of energy called the Sunyaev-Zel’dovich Effect...