Most Distant Quasar Opens Window Into Early Universe

by Vanessa D'Amico on July 1, 2011

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Quasar

Quasar

Astronomers have uncovered yet another clue in their quest to understand the Universe’s early life: the most distant quasar ever observed. At a redshift of 7.1, it is a relic from when the cosmos was just 770 million years old – just 5% of its age today.

Quasars are extremely old, outrageously luminous balls of radiation that were prevalent in the early Universe. Each is thought to have been fueled at its core by an incredibly powerful supermassive black hole. The most recent discovery (which carries the romantic name ULAS J1120+0641) is noteworthy for a couple of reasons. First of all, its supermassive black hole weighs approximately two billion solar masses – an impressive feat of gravity so soon after the Big Bang. It is also incredibly bright, given its great distance. “Objects that lie at such large distance are almost impossible to find in visible-light surveys because their light is stretched by the expansion of the universe,” said Dr. Simon Dye of the University of Nottingham, a member of the team that discovered the object. “This means that by the time their light gets to Earth, most of it ends up in the infrared part of the electromagnetic spectrum.” Due to these effects, only about 100 visible quasars exist in the sky at redshifts higher than 7.

Up until recently, the most distant quasar observed was at a redshift of 6.4; but thanks to this discovery, astronomers can probe 100 million years further into the history of the Universe than ever before. Careful study of ULAS J1120+0641 and its properties will enable scientists to learn more about galaxy formation and supermassive black hole growth in early epochs. The research was published in the June 30 issue of Nature.

For further reading, see related paper by Chris Willot, Monster in the Early Universe

Source: EurekAlert

Lord Haw-Haw. July 1, 2011 at 12:37 PM

Superb article Vanessa….. Quasars are out of this World!

Jon Hanford July 1, 2011 at 4:08 PM

The discovery of SMBHs at redshifts higher than z=6 is problematic for models of BH growth by means of Eddington-limited gas accretion only. It seems that formation of LMBH (below ~300 M_Sun) from remnants of Pop III stars cannot reasonably reproduce the observed population of early SMBHs.

Another route to early SMBHs being explored is the formation of massive ‘seed’ black holes (10E5 to 10E6 M_Sun) in the early universe.

These MBHs may have formed from the direct collapse of pre-galactic gas discs: http://arxiv.org/PS_cache/arxiv/pdf/0709/0709.0529v2.pdf (and refs therein)

Another scenario invokes the runaway collapse of early nuclear star clusters (and large quantities of surrounding gas) to form these seed MBHs: http://arxiv.org/PS_cache/arxiv/pdf/1106/1106.5943v1.pdf

In both of these scenarios, subsequent Eddington-limited accretion by these seed MBHs would lead to the observed SMBHs at z=6 and higher.

Anonymous July 1, 2011 at 9:38 PM

Once I attended a talk, where the speaker presented the possibility that a “self-gravitating” disk could feed a black hole much faster than a “normal” disk. In the standard scenarios the gravitational potential of the disk is neglected. But by introducing it into the equations it was possible to grow supermassive black holes quite quickly, even with the trend that a more massive hole grows faster.

Anonymous July 2, 2011 at 12:11 PM

A self gravitating disk would have to be pretty compact. The gravity field has potential energy which if large enough can become a significant percentage of the mass-energy. Hence the disk might then have a large ADM energy, or energy measure as determined by the deviation of the spacetime metric near the matter relative to an asymptotically flat region.

This still raises some questions about how such a distribution of matter occurred. I am not sufficiently knowledgeable on the formation of PopIII stars, but maybe their stellar nurseries of hydrogen gas continue to implode onto these stars long after their formation and explosive/implosive deaths into black holes. Since the matter is hydrogen it is less likely to be blown away by the ignition of these PopIII stars and so rather than dissipating away as dusty nebular clouds to now they might just continue to collapse inwards. This then might entail the early stellar phase of the universe had impressive and essentially opaque hydrogen nebulae.

LC

Anonymous July 2, 2011 at 11:52 AM

This is quite troubling. The “obvious” solution is that such large black holes emerged from the earliest universe. Yet this changes a troublesome astrophysics problem into a horrid cosmological one. This would mean the earliest universe had very large entropy that is physically untenable. At z = 6 object is within 1 billion years after the big bang, and with no BHs in the universe until the onset of star formation it means this SMBH grew at the average rate of several stellar masses per year. That is tough for a 100M_{sol} BH to sustain.

Some of these models seem to suggest the environment involved with seeding black holes was different from what we observe to today.

LC

Richard Mitnick July 1, 2011 at 4:10 PM

Interested to know if the graphic with this post is an artist’s rendering.

Jon Hanford July 1, 2011 at 5:17 PM

Yeah, Richard, the graphic is an artist’s rendering of a ‘generic’ quasar for illustration purposes. A photograph of this quasar can be found here: http://www.eso.org/public/images/eso1122b/

Vanessa, the “Source” link given leads to the paper by Chris Willot, instead of EurekAlert.

Jon Hanford July 1, 2011 at 5:17 PM

Yeah, Richard, the graphic is an artist’s rendering of a ‘generic’ quasar for illustration purposes. A photograph of this quasar can be found here: http://www.eso.org/public/images/eso1122b/

Vanessa, the “Source” link given leads to the paper by Chris Willot, instead of EurekAlert.

Anonymous July 2, 2011 at 12:56 AM

What is great about this one is that they actually have a high-quality spectrum for the object – it is not simply a photometric ‘redshift’. This means that they can actually do great science with this object, like determining the metallicity of the host galaxy and much more.

Lord Haw-Haw. July 2, 2011 at 6:55 AM

The findings were published in “Nature” last Thursday June 30th. Please see:

http://www.eso.org/public/archives/releases/sciencepapers/eso1122/eso1122.pdf

A redshift of Z=7.085 certainly generates an enigma with Quasar ULAS J1120+0641 analogized by one picturesque observer as being akin to rolling a snowball down a hill only to find it had grown to twenty feet across.

Anonymous July 2, 2011 at 11:44 PM

An idea that is being kicked around by myself an others is that gravity waves play a role. The UT article above this on a “big rip” shows the Sloane wall and filaments. This appears remarkably similar to the light ripples you may see on the bottom of a swimming pool. These are light caustics due to the rippling motion of the water surface. The rippling surface results in concavity and convexity in the lensing of light. Similarly gravitons produced in the big bang are expanded into long wavelength gravity waves which focus the motion of radiation and matter into early universe into similar caustics. These caustics are what produced the filamentary structures. This physics then accelerated the bunching of matter and the subsequent formation of black holes,

LC

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