<?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>1870-3542</journal-id>
<journal-title><![CDATA[Revista mexicana de física E]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fís. E]]></abbrev-journal-title>
<issn>1870-3542</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1870-35422007000100002</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Fenómeno de lentes gravitacionales en el espacio-tiempo de Janis, Newman y Winicour]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Román-Hernández]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Santiago-Santiago]]></surname>
<given-names><![CDATA[J.G.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Silva-Ortigoza]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Suárez-Xique]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Zenteno-Mateo]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad Autónoma de Puebla Facultad de Ciencias Físico Matemáticas ]]></institution>
<addr-line><![CDATA[Puebla Pue.]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2007</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2007</year>
</pub-date>
<volume>53</volume>
<numero>1</numero>
<fpage>5</fpage>
<lpage>19</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1870-35422007000100002&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1870-35422007000100002&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1870-35422007000100002&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[En el presente trabajo integramos las ecuaciones que describen las geodésicas luxoides del cono de luz de un punto arbitrario en el espacio-tiempo de Janis, Newman y Winicour y construimos, en forma exacta, las ecuaciones que describen el fenómeno de lentes gravitacionales. Demostramos que bajo ciertas aproximaciones nuestros resultados exactos se reducen a la ecuación de lente delgada. Además, usamos nuestras ecuaciones exactas para reobtener los resultados obtenidos por Virbhadra y Ellis usando su ecuación, la cual, es aplicable en el límite de campo fuerte [18]. Es decir, mostramos que para, 0 < q/M < <img width=23 height=20 src="../../../../../img/revistas/rmfe/v53n1/a2s1.jpg">, el fenómeno de lentes gravitacionales en la solución de JNW es cualitativamente similar al que aparece en el agujero negro de Schwarzschild, y, para q/M > <img width=23 height=20 src="../../../../../img/revistas/rmfe/v53n1/a2s1.jpg">, el fenómeno de lentes gravitacionales, en estas dos soluciones, es totalmente diferente.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[In the present work we integrate the null geodesic equations of the light cone of an arbitrary point in the Janis, Newman and Winicour space-time and we construct, in an exact way, the equations that describe the gravitational lensing phenomenon. We show that under certain conditions our exact results reduce to the thin lens equation. Furthermore, we use our exact equations to reobtain the results obtained by Virbhadra and Ellis by using their strong field limit equation [18]. That is, we show that for, 0 < q/M < <img width=23 height=20 src="../../../../../img/revistas/rmfe/v53n1/a2s1.jpg">, the gravitational lensing phenomenon in the JNW solution is qualitatively similar to that due to a Schwarzschild black hole and that for, q/M > <img width=23 height=20 src="../../../../../img/revistas/rmfe/v53n1/a2s1.jpg">, the gravitational lensing phenomenon, in these two solutions, is totally different.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Lentes gravitacionales]]></kwd>
<kwd lng="en"><![CDATA[Gravitational lensing]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <p align="justify"><font face="verdana" size="4">Ense&ntilde;anza</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="4"><b>Fen&oacute;meno de lentes gravitacionales en el espacio&#150;tiempo de Janis, Newman y Winicour</b></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="2"><b>E. Rom&aacute;n&#150;Hern&aacute;ndez, J.G. Santiago&#150;Santiago, G. Silva&#150;Ortigoza, R. Su&aacute;rez&#150;Xique y B. Zenteno&#150;Mateo</b></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><i>Facultad de Ciencias F&iacute;sico Matem&aacute;ticas de la Universidad Aut&oacute;noma de Puebla, Apartado Postal 1152, 72001. Puebla, Pue., M&eacute;xico.</i></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">Recibido el 26 de agosto de 2005    <br>   Aceptado el 27 de marzo de 2006</font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>     <p align="justify"><font face="verdana" size="2">En el presente trabajo integramos las ecuaciones que describen las geod&eacute;sicas luxoides del cono de luz de un punto arbitrario en el espacio&#150;tiempo de Janis, Newman y Winicour y construimos, en forma exacta, las ecuaciones que describen el fen&oacute;meno de lentes gravitacionales. Demostramos que bajo ciertas aproximaciones nuestros resultados exactos se reducen a la ecuaci&oacute;n de lente delgada. Adem&aacute;s, usamos nuestras ecuaciones exactas para reobtener los resultados obtenidos por Virbhadra y Ellis usando su ecuaci&oacute;n, la cual, es aplicable en el l&iacute;mite de campo fuerte &#91;18&#93;. Es decir, mostramos que para, 0 &lt; <i>q/M &lt; <img src="/img/revistas/rmfe/v53n1/a2s1.jpg" alt="">, </i>el fen&oacute;meno de lentes gravitacionales en la soluci&oacute;n de JNW es cualitativamente similar al que aparece en el agujero negro de Schwarzschild, y, para <i>q/M &gt; <img src="/img/revistas/rmfe/v53n1/a2s1.jpg" alt="">, </i>el fen&oacute;meno de lentes gravitacionales, en estas dos soluciones, es totalmente diferente.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Descriptores: </b>Lentes gravitacionales.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>     <p align="justify"><font face="verdana" size="2">In the present work we integrate the null geodesic equations of the light cone of an arbitrary point in the Janis, Newman and Winicour space&#150;time and we construct, in an exact way, the equations that describe the gravitational lensing phenomenon. We show that under certain conditions our exact results reduce to the thin lens equation. Furthermore, we use our exact equations to reobtain the results obtained by Virbhadra and Ellis by using their strong field limit equation &#91;18&#93;. That is, we show that for, 0 &lt; <i>q/M &lt; <img src="/img/revistas/rmfe/v53n1/a2s1.jpg">, </i>the gravitational lensing phenomenon in the JNW solution is qualitatively similar to that due to a Schwarzschild black hole and that for, <i>q/M &gt; <img src="/img/revistas/rmfe/v53n1/a2s1.jpg" alt="">, </i>the gravitational lensing phenomenon, in these two solutions, is totally different.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Keywords: </b>Gravitational lensing.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">PACS: 04.20.Cv; 04.70.&#150;s; 95.30.Sf</font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmfe/v53n1/v53n1a2.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Agradecimientos</b></font></p>     <p align="justify"><font face="verdana" size="2">Los autores agradecen los comentarios de un &aacute;rbitro para mejorar la presentaci&oacute;n de los resultados. Los autores agradecen el apoyo econ&oacute;mico recibido de CONACyT a trav&eacute;s del proyecto 44515&#150;F. Adem&aacute;s G.S.O. agradece el apoyo econ&oacute;mico recibido del Sistema Nacional de Investigadores (M&eacute;xico). Este trabajo tambi&eacute;n fue apoyado parcialmente por la VIEP&#150;BUAP por medio del proyecto 17/I/EXC/05.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Referencias</b></font></p>     <!-- ref --><p align="justify"><font face="verdana" size="2">1. A. Einstein,<i> Annalen der Physik </i><b>35</b> (1911) 898.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8447100&pid=S1870-3542200700010000200001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">2. G.F. Torres del Castillo and C.I. P&eacute;rez S&aacute;nchez, <i>Rev. Mexi. 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