<?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>S0185-11012017000100113</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[An extension of the Miyamoto-Nagai potential formula]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Ninkovi&#263;]]></surname>
<given-names><![CDATA[Slobodan]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Astronomical Observatory  ]]></institution>
<addr-line><![CDATA[Belgrade ]]></addr-line>
<country>Serbia</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2017</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2017</year>
</pub-date>
<volume>53</volume>
<numero>1</numero>
<fpage>113</fpage>
<lpage>119</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0185-11012017000100113&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0185-11012017000100113&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0185-11012017000100113&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract A new formula for the gravitational potential for the case of steady state and axial symmetry is proposed. It is a generalization of the Miyamoto-Nagai formula, in that there is a fraction containing the terms of this formula in both the numerator and denominator. The number of independent parameters in the new formula is four. The formula can be applied to both weakly flattened and substantially flattened stellar systems (subsystems). However, in applying the new formula to an exponential disk, requiring the total mass to be equal, negative density values cannot be avoided completely. This concerns especially the positions off the midplane.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen Se propone una nueva fórmula para el potencial gravitatorio en el caso estacionario y con simetría cilíndrica. Es una generalización de la fórmula de Miyamoto y Nagai, con una fracción que contiene los términos de esta fórmula en el numerador y el denominador. El número de parámetros independientes en la fórmula nueva es cuatro. La fórmula se puede aplicar a sistemas (subsistemas) estelares tanto débilmente como sustancialmente achatados. Sin embargo, cuando la fórmula nueva se aplica a un disco exponencial, con iguales masas totales, no se pueden evitar completamente los valores negativos de la densidad. Esto se refiere especialmente a las posiciones fuera del plano de simetría.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Galaxy: disk]]></kwd>
<kwd lng="en"><![CDATA[galaxies: kinematics and dynamics]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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