Документ взят из кэша поисковой машины. Адрес оригинального документа : http://hea-www.harvard.edu/~dburke/PDL/hogg/lookback_time Дата изменения: Thu Aug 9 02:34:53 2001 Дата индексирования: Tue Oct 2 07:09:39 2012 Кодировка: Поисковые слова: universe

#
# Compare to fig 6, of Hogg, D. W., "Distance measures in cosmology",
# astro-ph/9905116
#
# Note:
# currently only do the lookback time, not the age of the universe
# curves
#

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 lookback times
my $d_a = $a->lookback_time( $z );
my $d_b = $b->lookback_time( $z );
my $d_c = $c->lookback_time( $z );

print "Note: only calculates the lookback times, not the age of the Universe curves\n";

# plot the graph
my $win = PDL::Graphics::PGPLOT::Window->new();

$win->env( 0, 5, 0, 1.2 );
$win->label_axes( "redshift z",
"lookback time t\\dL\\u/t\\dH\\u",
"Fig 6 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;