Quasar Dust in the Early Universe

Mar 26, 2010
Quasar Dust in the Early Universe
A Hubble image of a nearby quasar. New Spitzer Space Telescope infrared observations of distant quasars, objects whose light traces an early epoch of the universe (about 12 billion years ago), have discovered that some apparently date from a time before dust had been made, or at least before it was readily available. Credit: NASA Hubble Space Telescope

(PhysOrg.com) -- Quasars are galaxies whose very bright cores are thought to contain massive black holes around which disks are actively accreting matter.

The accretion process releases vast amounts of energy, and as a result are among the most powerful energy sources known. No one knows for sure, however, how these objects form, how they develop in time, or how exactly their stupendous energies are produced. Because they are so bright, quasars can be seen even when they are very far away, and this combination of being both highly energetic and located at cosmological distances makes them appealing to astronomers trying to figure out the nature of galactic center black holes (our own has one) and the conditions in the that prompt these monsters to form.

There are about forty quasars known to be so far away that their light has been traveling toward us for over twelve billion years; in other words, their were already glowing brightly when the universe was very young - less than one billion years old. The question is: do they look like nearby quasars, or are they different somehow? CfA astronomer Yue Shen is a member of an international team of twelve astronomers that has concluded that some remote quasars are very different indeed.

Using the Spitzer Space Telescope's sensitive infrared cameras, the scientists observed twenty-one distant quasars to see whether or not they could detect evidence for hot dust; such dust would be expected if there really is a hot accreting disk of material around a black hole. Indeed, hot dust is a characteristic feature of quasars in the local universe.

Remarkably, as the team reports in this week's issue of Nature, two of the quasars in their study show no evidence for hot dust. The implication is that these galaxies are so primitive (in cosmic terms) that there has not been time for them to make dust, presumably either because there has not been time to form enough of the required constituent chemical elements, or because there has not been time to assemble them into dust grains. The results suggest that these objects date from an epoch in the universe when dust was first being made. Dust is a key catalyst in turning atomic gas into the molecules that facilitate stellar birth and evolution, and this new result is significant not only for quasar research, but also for helping understand how the first few generation of stars in the universe came to be.

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User comments : 5

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5 / 5 (1) Mar 27, 2010
The implication is that these galaxies are so primitive (in cosmic terms) that there has not been time for them to make dust
Now we need only to know how these "primitive" galaxies came into being ...
1.6 / 5 (5) Mar 27, 2010
Neutron repulsion is the energy source at the cores of galaxies.

Neutron-emission followed by neutron-decay generates the Hydrogen that fills interstellar space.

This story is summarized in a U-tube video of "Nellie the Neutron."

With kind regards,
Oliver K. Manuel
Emeritus Professor
Nuclear and Space Studies
Former NASA PI for Apollo
4.8 / 5 (4) Mar 27, 2010
This story is based on the same info that was reported here recently as "Astronomers observe fast growing primitive black holes" from 3-17-10. As I posted there:

"Dust-free quasars in the early universe" has been posted online: http://arxiv.org/...3432.pdf

There is extensive discussion of other distant QSOs studied containing varying amounts of dust, but these dustless specimens are indeed quite a find.
5 / 5 (4) Mar 27, 2010
Dr Manuel,

A sad day indeed to see a "scientist" with your credentials feel the need to promote your personal theory through "a U-tube video of "Nellie the Neutron"" that in no way explains (or even mentions) your theory of neutron repulsion. I see this video is to be one of a series, aimed at junior high to high school students (or those with equivalent educations). That you would even associate yourself with others using such tactics, similar to those used by "Electric Universe" and creationist proponents, speaks volumes about your personal integrity. What's next, Nellie the Neutron coloring books?
1 / 5 (2) Mar 30, 2010
Relax, yyz.

Methods of communication are evolving. Sometimes a picture is worth a thousand words.

For example, strongly attractive interactions between the Neutron (N) and the Proton (P) in the nucleus:


Are much like the strongly attractive interactions of the North and South ends of an ordinary pole magnet:


In that visualization, the nucleus of O-16 looks like eight pole magnets:


With kind regards,
Oliver K. Manuel
Emeritus Profesor
Nuclear & Space Studies
Former NASA PI for Apollo