<?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>S0185-11012005000100005</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[A simple method to compensate softening effects in N-body simulations of spherical stellar systems]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Muzzio]]></surname>
<given-names><![CDATA[J. C.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Observatorio Astronómico  ]]></institution>
<addr-line><![CDATA[La Plata Buenos Aires]]></addr-line>
<country>Argentina</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2005</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2005</year>
</pub-date>
<volume>41</volume>
<numero>1</numero>
<fpage>41</fpage>
<lpage>44</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0185-11012005000100005&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0185-11012005000100005&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0185-11012005000100005&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[La simulación de sistemas estelares requiere, primero, crear un modelo y, luego, seguir su evolución mediante la integración numérica de las ecuaciones del movimiento. Los modelos pueden generarse a partir de distribuciones teóricas obtenidas del potencial Newtoniano, pero la integración requiere recurrir a potenciales ablandados para reducir los efectos de relajamiento. Habitualmente, la diferencia entre ambos potenciales solo causa alteraciones insignificantes en el modelo, pero en ciertos casos (por ejemplo, distribuciones muy concentradas) puede alterarlos en forma substancial. Aquí presentamos un método simple, independiente del modelo, que corrige este problema en simulaciones de sistemas estelares esféricos.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Simulations of stellar systems involve, first, creating a model and, subsequently, following its evolution through numerical integration of the equations of motion. The models can be generated from theoretical distributions obtained from the Newtonian potential, but the integration demands resorting to softened potentials in order to reduce relaxation effects. Usually, the difference between both potentials causes only negligible alterations in the model, but in some cases (e.g., cuspy distributions) it can substantially alter it. Here we present a model-independent simple method to correct this problem in simulations of spherical stellar systems.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Galaxies]]></kwd>
<kwd lng="en"><![CDATA[Globular clusters]]></kwd>
<kwd lng="en"><![CDATA[Methods]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[    	    <p align="center"><font face="verdana" size="4"><b>A simple method to compensate softening effects in  N&#45;body simulations of spherical  stellar systems</b></font></p>     <p align="center">&nbsp;</p> 	    <p align="center"><font face="verdana" size="2"><b>J. C. Muzzio</b></font></p>     <p align="center">&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2"><i>Observatorio Astron&oacute;mico, Paseo del Bosque s/n, 1900 La Plata, Argentina</i> (<a href="mailto:jcmuzzio@fcaglp.unlp.edu.ar">jcmuzzio@fcaglp.unlp.edu.ar</a>).</font></p>    <p align="justify">&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2">Received 2004 August 6    <br> Accepted 2004 November 9</font></p>  	    <p align="justify">&nbsp;</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">La simulaci&oacute;n de sistemas estelares requiere, primero, crear un modelo y, luego, seguir su evoluci&oacute;n mediante la integraci&oacute;n num&eacute;rica de las ecuaciones del movimiento. Los modelos pueden generarse a partir de distribuciones te&oacute;ricas obtenidas del potencial Newtoniano, pero la integraci&oacute;n requiere recurrir a potenciales ablandados para reducir los efectos de relajamiento. Habitualmente, la diferencia entre ambos potenciales solo causa alteraciones insignificantes en el modelo, pero en ciertos casos (por ejemplo, distribuciones muy concentradas) puede alterarlos en forma substancial. Aqu&iacute; presentamos un m&eacute;todo simple, independiente del modelo, que corrige este problema en simulaciones de sistemas estelares esf&eacute;ricos.</font></p>     <p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><b>ABSTRACT</b></font></p>     <p align="justify"><font face="verdana" size="2">Simulations of stellar systems involve, first, creating a model and, subsequently, following its evolution through numerical integration of the equations of motion. The models can be generated from theoretical distributions obtained from the Newtonian potential, but the integration demands resorting to softened potentials in order to reduce relaxation effects. Usually, the difference between both potentials causes only negligible alterations in the model, but in some cases (e.g., cuspy distributions) it can substantially alter it. Here we present a model&#45;independent simple method to correct this problem in simulations of spherical stellar systems.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Key Words:</b> Galaxies: Spherical &#151; Globular clusters &#151; Methods: N&#45;body.</font></p>     <p align="justify">&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmaa/v41n1/v41n1a5.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>        <p align="justify">&nbsp;</p>        <p align="justify"><font face="verdana" size="2"><b>REFERENCES</b></font></p>  	    ]]></body>
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