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The Quasar Conundrum
A short article on a recent discovery of a new quasar
Date : 08/03/2016
Author Information
Uploaded by : Hannah
Uploaded on : 08/03/2016
Subject : Physics
A recent astronomical discovery has left scientists feeling baffled, but excited, for future investigation into the early Universe. A quasar has been observed that is much more luminous and massive than current theory would indicate possible for its age. So, what is the next step? How has a quasar managed to become so large in such a short amount of time? Most importantly, what actually is a quasar?
In 1963, an incredibly luminous and powerful object was discovered in the night sky. This was the first observation of a quasar . It took years for scientists to understand the nature of quasars, but most now believe that they can be explained with the idea of the black hole. The name black hole is somewhat deceiving as they re actually objects, not holes. These objects are so dense and massive that the gravitational pull stops light escaping, hence making it look and act like a hole sucking everything in.
It is thought that at the centre of nearly every galaxy sits a supermassive black hole - a black hole that s millions of times the mass of our Sun. Quasars are believed to surround and be driven by these supermassive black holes which pull in matter and superheat it. The super-heated matter then shines - like when you heat a metal rod until it glows white hot - and causes the high luminosity of the quasar. Most astronomers today believe that a quasar is part of a supermassive black hole but whether we see it as a quasar depends on what direction it is facing in. The light (and other types of radiation) of the quasar is beamed out in two polar directions, so if it is facing us then we observe the substantial amounts of light and radiation, if not we observe the same phenomenon from a different angle and class it as a black hole at the centre of an active galaxy[1].
Recently, however, cosmologists have discovered something that doesn t quite fit in with how we thought they formed. The recent discovery of one of the most massive quasars known, SDSS J0100+2802 , is causing scientists to reevaluate current theory. It is 40,000 times as bright as all of the stars of the Milky Way put together and is expelling energy at 4.13 trillion times the rate of our sun[2]. The redshift of this quasar was measured to be 6.30 using this value cosmologists have been able to calculate that this quasar is 12.8 billion light-years away from Earth - that is, about 3.84 million billion kilometres. From this, the estimated age of the quasar as we see it places it at about 900 million years after the Big Bang. This makes it the brightest quasar powered by the most supermassive black hole of the early Universe[3]. However, this is where evidence conflicts with theory.
According to current theory and models of how quasars form, it is not possible for a quasar to be as large as SDSS J0100+2802 at the age of 900 million years. The quasar gained more mass than is expected for such a short period of time. So, one may ask, what is next? In Nature, a prominent scientific journal, the leader of the study Professor Xue-Bing Wu, reported that they re excited (it) will help us to probe more about the early universe [4].
US co-author Dr Yuri Beletsky, from the Carnegie Institution in Washington DC[4] theorises that in the early Universe the black holes must have grown at a faster rate than their host galaxies. To confirm this, more research will need to be done to investigate the formation of astronomical objects. By reevaluating how black holes and quasars could have formed in the early Universe, scientists can hope to explain how SDSS J0100+2802 managed to grow so large in this timescale. In turn, this could lead to the improvement of current models and further our understanding of the nature of the early Universe.
References[1] Black holes, quasars and active galaxies , D.Macchetto, http://www.spacetelescope.org/science/black_holes/, 31 March 2015[2] SDSS J0100+2802 , http://en.wikipedia.org/wiki/SDSS_J0100%2B2802, 31 March 2015[3] Ancient quasar with massive black hole found at cosmic dawn , http://astronomynow.com/2015/02/25/ancient-quasar-at-cosmic-dawn-found-with-massive-black-hole/, 31 March 2015
In 1963, an incredibly luminous and powerful object was discovered in the night sky. This was the first observation of a quasar . It took years for scientists to understand the nature of quasars, but most now believe that they can be explained with the idea of the black hole. The name black hole is somewhat deceiving as they re actually objects, not holes. These objects are so dense and massive that the gravitational pull stops light escaping, hence making it look and act like a hole sucking everything in.
It is thought that at the centre of nearly every galaxy sits a supermassive black hole - a black hole that s millions of times the mass of our Sun. Quasars are believed to surround and be driven by these supermassive black holes which pull in matter and superheat it. The super-heated matter then shines - like when you heat a metal rod until it glows white hot - and causes the high luminosity of the quasar. Most astronomers today believe that a quasar is part of a supermassive black hole but whether we see it as a quasar depends on what direction it is facing in. The light (and other types of radiation) of the quasar is beamed out in two polar directions, so if it is facing us then we observe the substantial amounts of light and radiation, if not we observe the same phenomenon from a different angle and class it as a black hole at the centre of an active galaxy[1].
Recently, however, cosmologists have discovered something that doesn t quite fit in with how we thought they formed. The recent discovery of one of the most massive quasars known, SDSS J0100+2802 , is causing scientists to reevaluate current theory. It is 40,000 times as bright as all of the stars of the Milky Way put together and is expelling energy at 4.13 trillion times the rate of our sun[2]. The redshift of this quasar was measured to be 6.30 using this value cosmologists have been able to calculate that this quasar is 12.8 billion light-years away from Earth - that is, about 3.84 million billion kilometres. From this, the estimated age of the quasar as we see it places it at about 900 million years after the Big Bang. This makes it the brightest quasar powered by the most supermassive black hole of the early Universe[3]. However, this is where evidence conflicts with theory.
According to current theory and models of how quasars form, it is not possible for a quasar to be as large as SDSS J0100+2802 at the age of 900 million years. The quasar gained more mass than is expected for such a short period of time. So, one may ask, what is next? In Nature, a prominent scientific journal, the leader of the study Professor Xue-Bing Wu, reported that they re excited (it) will help us to probe more about the early universe [4].
US co-author Dr Yuri Beletsky, from the Carnegie Institution in Washington DC[4] theorises that in the early Universe the black holes must have grown at a faster rate than their host galaxies. To confirm this, more research will need to be done to investigate the formation of astronomical objects. By reevaluating how black holes and quasars could have formed in the early Universe, scientists can hope to explain how SDSS J0100+2802 managed to grow so large in this timescale. In turn, this could lead to the improvement of current models and further our understanding of the nature of the early Universe.
References[1] Black holes, quasars and active galaxies , D.Macchetto, http://www.spacetelescope.org/science/black_holes/, 31 March 2015[2] SDSS J0100+2802 , http://en.wikipedia.org/wiki/SDSS_J0100%2B2802, 31 March 2015[3] Ancient quasar with massive black hole found at cosmic dawn , http://astronomynow.com/2015/02/25/ancient-quasar-at-cosmic-dawn-found-with-massive-black-hole/, 31 March 2015
[4] Black hole that`s 12 billion times bigger than the sun discovered , J. von Radowitz, http://www.independent.ie/world-news/black-hole-thats-12-billion-times-bigger-than-the-sun-discovered-31022716.html, 31 March 2015
This resource was uploaded by: Hannah