<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>wCDM — Astropy v0.2.4</title> <link rel="stylesheet" href="../_static/bootstrap-astropy.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '0.2.4', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="shortcut icon" href="../_static/astropy_logo.ico"/> <link rel="top" title="Astropy v0.2.4" href="../index.html" /> <link rel="up" title="Cosmological Calculations (astropy.cosmology)" href="../cosmology/index.html" /> <link rel="next" title="wpwaCDM" href="astropy.cosmology.core.wpwaCDM.html" /> <link rel="prev" title="w0wzCDM" href="astropy.cosmology.core.w0wzCDM.html" /> </head> <body> <div class="topbar"> <a class="brand" title="Documentation Home" href="../index.html"></a> <ul> <li><a class="homelink" title="AstroPy Homepage" href="http://www.astropy.org"></a></li> <li><a title="General Index" href="../genindex.html">Index</a></li> <li><a title="Python Module Index" href="../py-modindex.html">Modules</a></li> <li> <form action="../search.html" method="get"> <input type="text" name="q" placeholder="Search" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </li> </ul> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right"> <a href="astropy.cosmology.core.wpwaCDM.html" title="wpwaCDM"> next » </a> </li> <li class="right"> <a href="astropy.cosmology.core.w0wzCDM.html" title="w0wzCDM"> « previous </a> | </li> <li> <a href="../index.html">Astropy v0.2.4</a> » </li> <li><a href="../cosmology/index.html" accesskey="U">Cosmological Calculations (<tt class="docutils literal"><span class="pre">astropy.cosmology</span></tt>)</a> »</li> <li>wCDM</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="wcdm"> <h1>wCDM<a class="headerlink" href="#wcdm" title="Permalink to this headline">¶</a></h1> <dl class="class"> <dt id="astropy.cosmology.core.wCDM"> <em class="property">class </em><tt class="descclassname">astropy.cosmology.core.</tt><tt class="descname">wCDM</tt><big>(</big><em>H0</em>, <em>Om0</em>, <em>Ode0</em>, <em>w0=-1.0</em>, <em>Tcmb0=2.725</em>, <em>Neff=3.04</em>, <em>name='wCDM'</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/cosmology/core.py#L1207" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/cosmology/core.html#wCDM"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.cosmology.core.wCDM" title="Permalink to this definition">¶</a></dt> <dd><p>Bases: <a class="reference internal" href="astropy.cosmology.core.FLRW.html#astropy.cosmology.core.FLRW" title="astropy.cosmology.core.FLRW"><tt class="xref py py-class docutils literal"><span class="pre">astropy.cosmology.core.FLRW</span></tt></a></p> <p>FLRW cosmology with a constant dark energy equation of state and curvature.</p> <p>This has one additional attribute beyond those of FLRW.</p> <p class="rubric">Examples</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">astro.cosmology</span> <span class="kn">import</span> <span class="n">wCDM</span> <span class="gp">>>> </span><span class="n">cosmo</span> <span class="o">=</span> <span class="n">wCDM</span><span class="p">(</span><span class="n">H0</span><span class="o">=</span><span class="mi">70</span><span class="p">,</span> <span class="n">Om0</span><span class="o">=</span><span class="mf">0.3</span><span class="p">,</span> <span class="n">Ode0</span><span class="o">=</span><span class="mf">0.7</span><span class="p">,</span> <span class="n">w0</span><span class="o">=-</span><span class="mf">0.9</span><span class="p">)</span> </pre></div> </div> <p>The comoving distance in Mpc at redshift z:</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">dc</span> <span class="o">=</span> <span class="n">cosmo</span><span class="o">.</span><span class="n">comoving_distance</span><span class="p">(</span><span class="n">z</span><span class="p">)</span> </pre></div> </div> <p class="rubric">Attributes Summary</p> <table border="1" class="longtable docutils"> <colgroup> <col width="10%" /> <col width="90%" /> </colgroup> <tbody valign="top"> <tr class="row-odd"><td><a class="reference internal" href="#astropy.cosmology.core.wCDM.w0" title="astropy.cosmology.core.wCDM.w0"><tt class="xref py py-obj docutils literal"><span class="pre">w0</span></tt></a></td> <td>Dark energy equation of state</td> </tr> </tbody> </table> <p class="rubric">Methods Summary</p> <table border="1" class="longtable docutils"> <colgroup> <col width="10%" /> <col width="90%" /> </colgroup> <tbody valign="top"> <tr class="row-odd"><td><a class="reference internal" href="#astropy.cosmology.core.wCDM.de_density_scale" title="astropy.cosmology.core.wCDM.de_density_scale"><tt class="xref py py-obj docutils literal"><span class="pre">de_density_scale</span></tt></a>(z)</td> <td>Evaluates the redshift dependence of the dark energy density.</td> </tr> <tr class="row-even"><td><a class="reference internal" href="#astropy.cosmology.core.wCDM.efunc" title="astropy.cosmology.core.wCDM.efunc"><tt class="xref py py-obj docutils literal"><span class="pre">efunc</span></tt></a>(z)</td> <td>Function used to calculate H(z), the Hubble parameter.</td> </tr> <tr class="row-odd"><td><a class="reference internal" href="#astropy.cosmology.core.wCDM.inv_efunc" title="astropy.cosmology.core.wCDM.inv_efunc"><tt class="xref py py-obj docutils literal"><span class="pre">inv_efunc</span></tt></a>(z)</td> <td>Function used to calculate <span class="math">\frac{1}{H_z}</span>.</td> </tr> <tr class="row-even"><td><a class="reference internal" href="#astropy.cosmology.core.wCDM.w" title="astropy.cosmology.core.wCDM.w"><tt class="xref py py-obj docutils literal"><span class="pre">w</span></tt></a>(z)</td> <td>Returns dark energy equation of state at redshift <tt class="xref py py-obj docutils literal"><span class="pre">z</span></tt>.</td> </tr> </tbody> </table> <p class="rubric">Attributes Documentation</p> <dl class="attribute"> <dt id="astropy.cosmology.core.wCDM.w0"> <tt class="descname">w0</tt><a class="reference internal" href="../_modules/astropy/cosmology/core.html#wCDM.w0"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.cosmology.core.wCDM.w0" title="Permalink to this definition">¶</a></dt> <dd><p>Dark energy equation of state</p> </dd></dl> <p class="rubric">Methods Documentation</p> <dl class="method"> <dt id="astropy.cosmology.core.wCDM.de_density_scale"> <tt class="descname">de_density_scale</tt><big>(</big><em>z</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/cosmology/core.py#L1291" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/cosmology/core.html#wCDM.de_density_scale"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.cosmology.core.wCDM.de_density_scale" title="Permalink to this definition">¶</a></dt> <dd><p>Evaluates the redshift dependence of the dark energy density.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>z</strong> : array_like</p> <blockquote> <div><p>Input redshifts.</p> </div></blockquote> </td> </tr> <tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first"><strong>I</strong> : ndarray, or float if input scalar</p> <blockquote class="last"> <div><p>The scaling of the energy density of dark energy with redshift.</p> </div></blockquote> </td> </tr> </tbody> </table> <p class="rubric">Notes</p> <p>The scaling factor, I, is defined by <span class="math">\rho(z) = \rho_0 I</span>, and in this case is given by <span class="math">I = \left(1 + z\right)^{3\left(1 + w_0\right)}</span></p> </dd></dl> <dl class="method"> <dt id="astropy.cosmology.core.wCDM.efunc"> <tt class="descname">efunc</tt><big>(</big><em>z</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/cosmology/core.py#L1315" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/cosmology/core.html#wCDM.efunc"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.cosmology.core.wCDM.efunc" title="Permalink to this definition">¶</a></dt> <dd><p>Function used to calculate H(z), the Hubble parameter.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>z</strong> : array_like</p> <blockquote> <div><p>Input redshifts.</p> </div></blockquote> </td> </tr> <tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first"><strong>E</strong> : ndarray, or float if input scalar</p> <blockquote class="last"> <div><p>The redshift scaling of the Hubble consant.</p> </div></blockquote> </td> </tr> </tbody> </table> <p class="rubric">Notes</p> <p>The return value, E, is defined such that <span class="math">H(z) = H_0 E</span>.</p> </dd></dl> <dl class="method"> <dt id="astropy.cosmology.core.wCDM.inv_efunc"> <tt class="descname">inv_efunc</tt><big>(</big><em>z</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/cosmology/core.py#L1342" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/cosmology/core.html#wCDM.inv_efunc"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.cosmology.core.wCDM.inv_efunc" title="Permalink to this definition">¶</a></dt> <dd><p>Function used to calculate <span class="math">\frac{1}{H_z}</span>.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>z</strong> : array_like</p> <blockquote> <div><p>Input redshifts.</p> </div></blockquote> </td> </tr> <tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first"><strong>E</strong> : ndarray, or float if input scalar</p> <blockquote class="last"> <div><p>The inverse redshift scaling of the Hubble constant.</p> </div></blockquote> </td> </tr> </tbody> </table> <p class="rubric">Notes</p> <p>The return value, E, is defined such that <span class="math">H_z = H_0 / E</span>.</p> </dd></dl> <dl class="method"> <dt id="astropy.cosmology.core.wCDM.w"> <tt class="descname">w</tt><big>(</big><em>z</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/cosmology/core.py#L1267" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/cosmology/core.html#wCDM.w"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.cosmology.core.wCDM.w" title="Permalink to this definition">¶</a></dt> <dd><p>Returns dark energy equation of state at redshift <tt class="xref py py-obj docutils literal"><span class="pre">z</span></tt>.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>z</strong> : array_like</p> <blockquote> <div><p>Input redshifts.</p> </div></blockquote> </td> </tr> <tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first"><strong>w</strong> : ndarray, or float if input scalar</p> <blockquote class="last"> <div><p>The dark energy equation of state</p> </div></blockquote> </td> </tr> </tbody> </table> <p class="rubric">Notes</p> <p>The dark energy equation of state is defined as <span class="math">w(z) = P(z)/\rho(z)</span>, where <span class="math">P(z)</span> is the pressure at redshift z and <span class="math">\rho(z)</span> is the density at redshift z, both in units where c=1. Here this is <span class="math">w(z) = w_0</span>.</p> </dd></dl> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"><h3>Page Contents</h3> <ul> <li><a class="reference internal" href="#">wCDM</a></li> </ul> </div> </div> <div class="clearer"></div> </div> <footer class="footer"> <p class="pull-right"> <a href="../_sources/_generated/astropy.cosmology.core.wCDM.txt" rel="nofollow">Page Source</a> <a href="#">Back to Top</a></p> <p> © Copyright 2011-2013, The Astropy Developers.<br/> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3. Last built 22 Oct 2013. <br/> </p> </footer> </body> </html>