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			The '''Sołtan argument''' is an [[astrophysics\|astrophysical]] theory outlined in 1982 by [[Poland\|Polish]] [[astronomer]] Andrzej Sołtan. It maintains that if [[quasar]]s were powered by [[Accretion (astrophysics)\|accretion]] onto a [[supermassive black hole]], then such supermassive black holes must exist in our local universe as "dead" quasars.

			==History==

	~~They are typically~~ a ~~free website~~ that ~~are pre~~-~~designed for enabling businesses~~ of ~~every size in marking~~ the ~~presence on~~ the ~~internet~~ and ~~allows them~~ in ~~showcasing~~ the ~~product services and range through images, contents and various other elements~~. ~~Good luck on continue learning how~~ to ~~make a wordpress website~~. ~~PSD files are incompatible to browsers~~ and are ~~suppose to be converted~~ into ~~wordpress compatible files so~~ that ~~it opens up~~ in ~~browser. Dead links are listed out simply because it will negatively have~~ an ~~influence on~~ the ~~website'~~s ~~search engine rating~~. ~~If you have any issues pertaining to exactly where and how to use [http:~~//~~8128.co/v23 backup plugin]~~, ~~you can get in touch with us at~~ the ~~webpage. The top 4 reasons~~ to ~~use Business Word - Press Themes for a business website are~~:. <br><br>~~Word - Press~~ is ~~known as~~ the ~~most popular blogging platform all over~~ the ~~web and~~ is ~~used by millions~~ of ~~blog enthusiasts worldwide~~. ~~Some of the Wordpress development services offered by us are~~:. ~~Our Daily Deal Software plugin brings~~ the ~~simplicity~~ of ~~setting up~~ a ~~Word - Press blog to~~ the ~~daily deal space~~. ~~So if you want to create blogs or have a website for your business or for personal reasons~~, ~~you can take advantage~~ of ~~free Word - Press installation to get started~~. ~~Aided by~~ the ~~completely foolproof j - Query color selector, you're able~~ to ~~change~~ the ~~colors~~ of ~~factors~~ of ~~your theme a the click on the screen, with very little previous web site design experience.~~ <br><br>~~The entrepreneurs can easily captivate their readers by using these versatile themes~~. ~~After sending these details~~, ~~your Word - Press blog will~~ be ~~setup~~ within a few ~~days~~. ~~You've got invested a great cope~~ of ~~time developing and producing up~~ the ~~topic substance~~. ~~Newer programs allow website owners and internet marketers to automatically and dynamically change words in their content to match the keywords entered by their web visitors in their search queries'~~a ~~feat~~ that ~~they cannot easily achieve with older software~~. ~~After that~~ the ~~developer adds the unordered list for navigations~~. <br><br>~~The disadvantage is it requires a considerable amount~~ of ~~time to set every thing up. * Robust CRM to control and connect with your subscribers. re creating a Word~~ - ~~Press design yourself~~, the ~~good news is there are tons~~ of ~~Word -~~ Press ~~themes to choose from~~. ~~IVF~~ ,~~fertility,infertility expert,surrogacy specialist~~ in ~~India at Rotundaivf. Look for experience: When you are searching for a Word~~ - ~~Press developer you should always look at their experience level.~~ <br><br>~~More it extends numerous opportunities where your firm~~ is ~~at comfort and rest assured~~ of ~~no risks & errors. An ease~~ of ~~use which pertains to both internet site back-end and front-end users alike~~. ~~As a result~~, ~~it is really crucial to just take aid of some experience when searching for superior quality totally free Word - Press themes~~, ~~Word - Press Premium Themes for your web site~~. ) ~~Remote Login~~: ~~With~~ the ~~process~~ of ~~PSD to Wordpress conversion comes~~ the ~~advantage of flexibility. For your information, it is an open source web content management system.~~		As early as 1969, [[Donald Lynden-Bell]] wrote a paper suggesting that "dead quasars" were found at the center of the [[Milky Way]] and nearby galaxies by arguing that given the quasar-number counts, luminosities, distances, and the efficiency of accretion into a "Schwarzschild throat" through the [[Photon sphere\|last stable circular orbit]] (note that the term ''[[black hole]]'' had been coined only two years earlier and was still gaining popular usage), roughly 10<sup>10</sup> quasars existed in the [[observable universe]]. This number density of "dead quasars" was attributed by Lynden-Bell to high [[mass-to-light ratio]] objects found at the center of galaxies. This is essentially the Sołtan argument, though the direct connection between black hole masses and quasar [[luminosity function (astronomy)\|luminosity function]]s is missing. In the paper, Lynden-Bell also suggests some radical ideas that are now fully integrated into modern understanding of astrophysics including the model that [[accretion disks]] are supported by [[magnetic field]]s, that [[extragalactic cosmic ray]]s are accelerated in them, and he estimates to within an order of magnitude the masses of several of the closest [[supermassive black hole]]s including the ones in the [[Milky Way]], [[Andromeda galaxy\|M31]], [[Messier 32\|M32]], [[Messier 81\|M81]], [[Messier 82\|M82]], [[Messier 87\|M87]], and [[NGC 4151]].<ref>{{cite journal
			\| author = Lynden-Bell, D.
			\| title = Galactic Nuclei as Collapsed Old Quasars
			\| journal = Nature
			\|date=August 1969
			\| volume = 223
			\| issue = 5207
			\| pages = 690–694
			\| bibcode = 1969Natur.223..690L
			\| doi = 10.1038/223690a0
			}}</ref>

			Thirteen years later, Sołtan explicitly showed that the [[luminosity]] (<math>L</math>) of quasars was due to the accretion rate of mass onto black holes given by:

			<math>L = \epsilon \dot{M} c^2</math>

			where

			*<math>\epsilon</math> is the efficiency factor
			*<math>\dot{M}</math> is the [[time rate]] of mass falling into the black hole
			*<math>c</math> is the [[speed of light]]<ref name=F&F>{{cite journal
			\| author = Ferrarese, L. and Ford, H.
			\| title = Supermassive Black Holes in Galactic Nuclei: Past, Present and Future Research
			\| journal = Space Science Reviews
			\|date=February 2005
			\| volume = 116
			\| issue = 3–4
			\| pages = 523–624
			\| doi = 10.1007/s11214-005-3947-6
			\| bibcode = 2005SSRv..116..523F
			\|arxiv = astro-ph/0411247 }}</ref>

			Given the number of observed quasars at various [[redshift]]s, he was able to derive an [[integral\|integrated]] [[energy density]] due to quasar output. Since observers on Earth are [[flux limit]]ed, there are always more quasars that exist than are observed and thus the energy density he derived is a [[lower bound]]. He obtained the value of approximately 10<sup>−10</sup> [[erg]]s per [[cubic meter]].<ref name=Soltan>{{cite journal
			\| author = Sołtan, A.
			\| title = Masses of quasars,
			\| journal = Monthly Notices of the Royal Astronomical Society
			\|date=July 1982
			\| volume = 200
			\| pages = 115–122
			\| bibcode = 1982MNRAS.200..115S
			}}</ref>

			Sołtan calculated the mass density of accreted material as it is directly related to the energy density of quasar light. He derived a value of approximately 10<sup>14</sup> [[solar mass]]es per cubic [[Gigaparsec]]. This mass would be [[discrete probability distribution\|discretely distributed]] (since quasars are single point sources); given an average mass of approximately ten million solar masses, it would be statistically likely for a "dead quasar" to be within a few [[megaparsec]]s of Earth.<ref name=Soltan />

			At this time, evidence was already accumulating that supermassive black holes were found at the center of large galaxies, which are distributed approximately on the order of a megaparsec apart from each other. This argument therefore made a reasonable case that supermassive black holes were at one time ultraluminous quasars.

			The first quantitative estimates of the mass density in supermassive black holes were 5-10 times higher than Soltan's estimate.<ref>Magorrian, J. et al. (1998), [http://adsabs.harvard.edu/abs/1998AJ....115.2285M The Demography of Massive Dark Objects in Galaxy Centers], ''The Astronomical Journal'', '''115''', 2285-2305</ref> This discrepancy was resolved in 2000 via the discovery of the [[M-sigma relation]], which showed that most of the previously-published black hole masses were in error.<ref name=DEGN>{{cite book\|last=Merritt\|first=David\|author-link=David Merritt\|title=Dynamics and Evolution of Galactic Nuclei\|year=2013\|publisher=Princeton University Press\|location=Princeton, NJ\|url=http://openlibrary.org/works/OL16802359W/Dynamics_and_Evolution_of_Galactic_Nuclei}}</ref>

			==Present constraints==

			As of 2008, the best constraints for the supermassive black hole mass per cubic megaparsec in the local universe derived from the Sołtan argument is between 2 - 5 x 10<sup>5</sup> solar masses. This value is consistent with observations of the mass of local supermassive black holes.<ref>[[David Merritt\|Merritt, D.]] and Ferrarese, L. (January 2001). [http://adsabs.harvard.edu/abs/2001MNRAS.320L..30M "Black Hole Demographics from the M-sigma Relation"]. ''Monthly Notices of the Royal Astronomical Society'' '''320''': L30-L34</ref>

			== See also ==

			# [[Supermassive black holes]]
			# [[M-sigma relation]]

			==References==
			{{reflist}}

			{{DEFAULTSORT:Soltan Argument}}
			[[Category:Quasars\|*]]
			[[Category:Supermassive black holes]]
			[[Category:Astrophysics]]
			[[Category:Extragalactic astronomy]]

en>Michael Hardy at 04:57, 2 September 2012

2012-09-02T04:57:44Z

New page

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en>Addbot: Bot: Migrating 4 interwiki links, now provided by Wikidata on d:q1062934

en>Michael Hardy at 04:57, 2 September 2012