<?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>0035-001X</journal-id>
<journal-title><![CDATA[Revista mexicana de física]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fis.]]></abbrev-journal-title>
<issn>0035-001X</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0035-001X2007001000010</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Determinación del espín de agujeros negros]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Fernández-Hernández]]></surname>
<given-names><![CDATA[L. M]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Ureña-López]]></surname>
<given-names><![CDATA[L. A]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad de Guanajuato Instituto de Física ]]></institution>
<addr-line><![CDATA[León Guanajuato]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>08</month>
<year>2007</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>08</month>
<year>2007</year>
</pub-date>
<volume>53</volume>
<fpage>46</fpage>
<lpage>50</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2007001000010&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2007001000010&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2007001000010&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Presentamos un resumen de la teoría detrás de los modelos de discos de acreción alrededor de agujeros negros. Asumiendo perturbaciones lineales, se encuentran dos modos principales de vibración del disco de acreción, que producen modulación del flujo de rayos X emitidos por el mismo. Se muestra la determinación de la masa y el espín para un ejemplo concreto de un candidato a agujero negro.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[We present a summary of the theory of accretion disks around black holes. In the regime of linear perturbation, we find the normal modes of vibration of the accretion disk that modulate the emission of X-ray bursts. An example is shown for the determination of the mass and spin of a particular black hole candidate.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Agujeros negros]]></kwd>
<kwd lng="es"><![CDATA[discos de acreción]]></kwd>
<kwd lng="en"><![CDATA[Black holes]]></kwd>
<kwd lng="en"><![CDATA[accretion disks]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <p align="center"><font face="verdana" size="4"><b>Determinaci&oacute;n del esp&iacute;n de agujeros negros</b></font></p>     <p align="center"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="2"><b>L. M. Fern&aacute;ndez&#150;Hern&aacute;ndez y L. A. Ure&ntilde;a&#150;L&oacute;pez </b></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><i>Instituto de F&iacute;sica de la Universidad de Guanajuato,</i><i> 37150, Le&oacute;n, Guanajuato, M&eacute;xico,     <br> e&#150;mail: <a href="mailto:lizbeth@fisica.ugto.mx" target="_blank">lizbeth@fisica.ugto.mx</a>, <a href="mailto:lurena@fisica.ugto.mx" target="_blank">lurena@fisica.ugto.mx</a></i></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">Recibido el 1 de mayo de 2006    <br> Aceptado el 1 de noviembre de 2006</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>     <p align="justify"><font face="verdana" size="2">Presentamos un resumen de la teor&iacute;a detr&aacute;s de los modelos de discos de acreci&oacute;n alrededor de agujeros negros. Asumiendo perturbaciones lineales, se encuentran dos modos principales de vibraci&oacute;n del disco de acreci&oacute;n, que producen modulaci&oacute;n del flujo de rayos X emitidos por el mismo. Se muestra la determinaci&oacute;n de la masa y el esp&iacute;n para un ejemplo concreto de un candidato a agujero negro.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Descriptores: </b>Agujeros negros; discos de acreci&oacute;n.</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">We present a summary of the theory of accretion disks around black holes. In the regime of linear perturbation, we find the normal modes of vibration of the accretion disk that modulate the emission of X&#150;ray bursts. An example is shown for the determination of the mass and spin of a particular black hole candidate.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Keywords: </b>Black holes; accretion disks.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">PACS: 97.60.Lf; 04.70.&#150;s</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v53s4/v53s4a10.pdf">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>Acknowledgments</b></font></p>     <p align="justify"><font face="verdana" size="2">LMF&#150;H agradece las becas de maestr&iacute;a otorgadas por CONACYT y CONCYTEG. Otros apoyos parciales para este trabajo son: los proyectos CONACYT (42748, 46195 y 47641); CONCYTEG (05&#150;16&#150;K117&#150;032); PROMEP (UGTO&#150;CA&#150;3) y DINPO (000085).</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><i>i</i> Este es una versi&oacute;n muy simplificada del ciclo de vida de una estrella. Informaci&oacute;n m&aacute;s detallada puede consultarse en las Refs. 1 y 3.</font></p>     <p align="justify"><font face="verdana" size="2"><i>ii</i> Menci&oacute;n aparte merece la llamada Radiaci&oacute;n de Hawking, la cual puede llevar a la evaporaci&oacute;n de un agujero negro. Sin embargo, esto ser&iacute;a un fenomeno importante s&oacute;lo en agujeros negros de poca masa &#91;12&#93;.</font></p>     <p align="justify"><font face="verdana" size="2"><i>iii   </i>Notese que hemos elegido unidades tales que G=c=1. </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>     ]]></body>
<body><![CDATA[<!-- ref --><p align="justify"><font face="verdana" size="2">1.  S.L. Shapiro y S.A. Teukolsky, <i>Blackholes, whitedwarfs, and</i><i> neutronstars: The physics of compact objects </i>(New York, USA: Wiley, 1983) p. 645.</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=8340271&pid=S0035-001X200700100001000001&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.&nbsp; &nbsp;C.W. Misner, K.S. Thorne y J.A. 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