Pristine gas from nascent universe

THE cold gas is flow­ing, they said, in­to a gal­axy that is now seen as it looked about 11 bil­lion years ago, due to the time its light takes to get he­re.
Pro­fuse gas flows like this are thought to be key to ex­plain­ing that early era, when ga­lax­ies were co­pi­ously form­ing stars from the gas. A si­m­i­lar flow could have con­tri­but­ed to the crea­t­ion of our own gal­axy.
The as­tro­no­mers – led by Neil Crigh­ton of Swin­burne Uni­vers­ity in the U.K. – pub­lished the find­ings Oct. 2 in the re­search jour­nal As­t­ro­phys­i­cal Jour­nal Let­ters.
The dis­tant hy­dro­gen usu­ally can't be de­tected. But in this case it was, thanks to a co­in­ci­den­tal light­ing ar­range­ment pro­vid­ed by a dis­tant, ex­tremely bright ob­ject known as a qua­sar, ac­cord­ing to Crigh­ton's group.
The find­ings came from a sys­tem­at­ic sur­vey us­ing the Large Bin­oc­u­lar Tel­e­scope on Mount Gra­ham, Ar­i­zo­na and an in­stru­ment called a spec­tro­graph on the Keck I tel­e­scope on the sum­mit of Mauna Kea, Ha­waii.
Cos­mol­o­gists be­lieve early ga­lax­ies re­ceived their ma­te­ri­al from a vast res­er­voir of pris­tine hy­dro­gen float­ing be­tween ga­lax­ies. About 10 bil­lion years ago when the uni­verse was one-fifth its cur­rent age, stud­ies have found, fledg­ling ga­lax­ies were form­ing new stars at nearly 100 times their cur­rent rate. This ac­ti­vity would re­quire some fu­el in the form of gas, since that is what makes up stars.
In the past dec­ade, su­per­com­puter sim­ula­t­ions of gal­axy forma­t­ion have pre­dicted that this gas fun­nels in­to ga­lax­ies along thin "cold streams" which, like streams of snow melt feed­ing a moun­tain lake, chan­nel cool gas from the sur­round­ing area on­to ga­lax­ies.
Test­ing these pre­dic­tions is­n't easy, as such gas at the edges of ga­lax­ies is very dark. In­stead, the team of as­tro­no­mers searched for places where qua­sars could pro­vide help­ful light. Quasars are ga­lax­ies that briefly shine as the bright­est ob­jects in the uni­verse as their cen­tral ob­ject, a black hole, sucks up ma­te­ri­al in a vi­o­lent pro­cess.

Source: World Science