<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0185-1101</journal-id>
<journal-title><![CDATA[Revista mexicana de astronomía y astrofísica]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. astron. astrofis]]></abbrev-journal-title>
<issn>0185-1101</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Instituto de Astronomía]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0185-11012018000100018</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Evolution of extragalactic radio sources and quasar/Galaxy unification]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Onah]]></surname>
<given-names><![CDATA[C. I.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Ubachukwu]]></surname>
<given-names><![CDATA[A. A.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Odo]]></surname>
<given-names><![CDATA[F. C.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Onuchukwu]]></surname>
<given-names><![CDATA[C. C.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Federal University of Technology Department of Physics ]]></institution>
<addr-line><![CDATA[Owerri ]]></addr-line>
<country>Nigeria</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,University of Nigeria Department of Physics &amp; Astronomy ]]></institution>
<addr-line><![CDATA[Nsukka ]]></addr-line>
<country>Nigeria</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Chukwuemeka Odumegwu Ojukwu University Department of Industrial Physics ]]></institution>
<addr-line><![CDATA[Uli Anambra State]]></addr-line>
<country>Nigeria</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2018</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2018</year>
</pub-date>
<volume>54</volume>
<numero>1</numero>
<fpage>0</fpage>
<lpage>0</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0185-11012018000100018&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0185-11012018000100018&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0185-11012018000100018&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract We use a large sample of radio sources to investigate the effects of evolution, luminosity selection and radio source orientation in explaining the apparent deviation of observed angular size redshift (&#952;&#8722;z) relation of extragalactic radio sources (EGRSs) from the standard model. We have fitted the observed &#952; &#8722; z data with standard cosmological models based on a flat universe (&#937;0 = 1). The size evolution of EGRSs has been described as luminosity, temporal and orientation-dependent in the form DP,z,&#966; &#8776; P±q(1 + z)&#8722;m sin&#966;, with q = 0.3, &#966; = 59&#9702;, m = &#8722;0.26 for radio galaxies and q = &#8722;0.5, &#966; = 33&#9702;, m = 3.1 for radio quasars respectively. Critical points of luminosity, log Pcrit = 26.33 WHz&#8722;1 and log Dc = 2.51 kpc (316.23 kpc) of the present sample of radio sources were also observed. All the results were found to be consistent with the popular quasar/galaxy unification scheme.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen Empleamos una muestra grande de radio-fuentes extra-galácticas (EGRS) para investigar los efectos evolutivos, de selección por luminosidad y de orientación sobre la aparente desviación respecto al modelo estándar observada para relación tamaño angular-corrimiento al rojo. Ajustamos los datos observados para &#952;&#8722;z con modelos cosmológicos estándar basados en un universo plano (&#937;0 = 1). Le evolución del tamaño de los EGRS se describe como dependiente de la luminosidad, del tiempo y de la orientación, en la forma DP,z,&#966; &#8776; P±q(1 + z)&#8722;m sin&#966; con q = 0.3, &#966; = 59º, m = &#8722;0.26 para radio-galaxias y q = &#8722;0.5, &#966; = 33º, m = 3.1 para radio cuasares. Se observaron también puntos críticos para la luminosidad, log Pcrit = 26.33 WHz&#8722;1 y log Dc = 2.51 kpc (316.23 kpc) en la muestra estudiada. Todos estos resultados concuerdan con el modelo unificado cuasar/galaxia.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[galaxies: active]]></kwd>
<kwd lng="en"><![CDATA[galaxies: evolution]]></kwd>
<kwd lng="en"><![CDATA[galaxies: general]]></kwd>
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