# # Compare to fig 5, of Hogg, D. W., "Distance measures in cosmology", # astro-ph/9905116 # use strict; use PDL; use PDL::Graphics::PGPLOT::Window; use Astro::Cosmology; # cosmologies - h0 is irrelevant here my $a = Astro::Cosmology->new( matter => 1.0, lambda => 0.0, h0 => 0.0 ); my $b = Astro::Cosmology->new( matter => 0.05, lambda => 0.0, h0 => 0.0 ); my $c = Astro::Cosmology->new( matter => 0.2, lambda => 0.8, h0 => 0.0 ); # z range my $z = 0.1 * sequence(51); # calculate the normalised comoving volume element # - ie the differential comoving volume element my $d_a = $a->dcomov_vol( $z ); my $d_b = $b->dcomov_vol( $z ); my $d_c = $c->dcomov_vol( $z ); # plot the graph my $win = PDL::Graphics::PGPLOT::Window->new(); $win->env( 0, 5, 0, 1.1 ); $win->label_axes( "redshift z", "comoving volume element [1/D\\dH\\u]\\u3\\d dV\\dc\\u/dz/d\\gW", "Fig 5 of Hogg, D.W. astro-ph/9905116 " . "[Astro::Cosmology v" . Astro::Cosmology->version . "]" ); $win->hold; $win->line( $z, $d_a, { LINESTYLE => 'solid' } ); $win->line( $z, $d_b, { LINESTYLE => 'dotted' } ); $win->line( $z, $d_c, { LINESTYLE => 'dashed' } ); $win->release; $win->close; ## End of the test exit;