Starship Asterisk*

[img3="Credit: NASA, ESA, and E. Glikman (Middlebury College)"]http://imgsrc.hubblesite.org/hu/db/imag ... _print.jpg[/img3][hr][/hr]

Quasars are the light fantastic. They are the brightest beacons in the universe, blazing across space with the intrinsic brightness of one trillion suns. Yet the objects are not vast galaxies, but they appear as pinpoint sources in the biggest telescopes of today — hence the term "quasar" for quasi-stellar object. Discovered in the 1960s, it took more than two decades of research to come to the conclusion that quasars are produced by the gusher of energy coming from over-fed supermassive black holes inside the cores of very distant galaxies. And, most quasars bloomed into a brief existence 12 billion years ago.

The big question has been, why? What was happening in the universe 12 billion years ago? The universe was smaller and so crowded that galaxies collided with each other much more frequently than today. Astronomers using Hubble's near-infrared vision tested this hypothesis by looking at dusty quasars where their glow was suppressed by dust, allowing a view of the quasar's surroundings. Hubble's sharp vision revealed chaotic collisions between galaxies that gave birth to quasars by fueling a supermassive central black hole.

• Astrophysical Journal 806(2) 218 (2015 Jun 20) DOI: 10.1088/0004-637X/806/2/218
  arXiv.org > astro-ph > arXiv:1504.02111 > 08 Apr 2015