ALMA Detects First Traces of Carbon 'Smog' in Early Galaxies

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ALMA Detects First Traces of Carbon 'Smog' in Early Galaxies

Post by bystander » Wed Jun 24, 2015 9:08 pm

ALMA Detects First Traces of Carbon ‘Smog’ Permeating Interstellar Atmospheres of Early Galaxies
ESO | NRAO | NAOJ | ALMA | 2015 Jun 24
[img3="Using ALMA, astronomers survey an array of normal galaxies seen when the Universe
was only 1 billion years old. The detected the glow of ionized carbon fulling the space
between the stars, indicating these galaxies were fully formed but chemically
immature, when compared to similar galaxies a few billion years later. The ALMA
data for four of these galaxies is show in relation to objects in the COSMOS field.
Credit: ALMA (NRAO/ESO/NAOJ), P. Capak; B. Saxton (NRAO/AUI/NSF)
"]http://www.almaobservatory.org/images/n ... pak_01.jpg[/img3][hr][/hr]
Astronomers study the elements scattered between the stars to learn about the internal workings of galaxies, their motion and chemistry. To date, however, attempts to detect the telltale radio signature of carbon in the very early Universe have been thwarted, perhaps – as some have speculated – by the need to allow a few billion years more for stars to manufacture sufficient quantities to be observed across such vast cosmic distances.

New observations with the Atacama Large Millimeter/submillimeter Array (ALMA), however, readily detected the first faint traces of carbon atoms permeating the interstellar atmospheres of so-called normal galaxies, seen only one billion years after the Big Bang. This suggests that even though normal galaxies in the very early Universe were already brimming with carbon, they were not nearly as chemically evolved as similar galaxies observed just a few billion years later. In these later galaxies most of the ionized carbon has condensed into dust grains -- simple organic molecules like carbon monoxide (CO). ...

ALMA, with its unprecedented sensitivity, was able to detect the faint but ubiquitous millimeter "glow" of ionized carbon in the interstellar atmospheres of nine very distant, very young galaxies seen when the Universe was only seven percent of its current age. Atoms like carbon can become ionized by the powerful ultraviolet radiation emitted by bright, massive stars.

When galaxies first assembled, during a period often referred to as "Cosmic Dawn," most of the space between the stars was filled with a mixture of hydrogen and helium produced in the Big Bang. As subsequent generations of massive stars ended their brief but brilliant lives as supernovas, they seeded the interstellar medium with a fine dust of heavy elements, mostly carbon, silicon, and oxygen, which are forged in their nuclear furnaces. ...

Discovering a New Stage in the Galactic Lifecycle
California Institute of Technology | 2015 Jun 24

Galaxies at redshifts 5 to 6 with systematically low dust content and high
emission - P. L. Capak et al
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