---
name: "astcosmiccal"
section: "1"
platform: "linux"
package: "gnuastro"
version: "0.23-2+b3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/astcosmiccal"
---

# astcosmiccal(1)

estimate cosmological values

## NAME

CosmicCalculator - estimate cosmological values

## SYNOPSIS

**astcosmiccal** \[*OPTION*...\]

## DESCRIPTION

CosmicCalculator is part of GNU Astronomy Utilities 0.23. CosmicCalculator will do cosmological calculations. If no redshfit is specified, it will only print the main input parameters. If only a redshift is given, it will print a table of all calculations. If any of the single row calculations are requested, only their values will be printed with a single space between each.

For more information, please run any of the following commands. In particular the second contains a very comprehensive explanation of CosmicCalculator's invocation: expected input(s), output(s), and a full description of all the options.

- All options and their values:

  $ astcosmiccal **-P**

- Inputs/Outputs and options:

  $ info astcosmiccal

- Full section in manual/book:

  $ info CosmicCalculator

- Full Gnuastro manual/book:

  $ info gnuastro

If you couldn't find your answer in the manual, you can get direct help from experienced Gnuastro users and developers. For more information, please run:

-

  `$ info help-gnuastro`

CosmicCalculator options:

-

  Input:

- **-H**, **--H0**=*FLT*

  Current expansion rate (Hubble constant).

- **-l**, **--olambda**=*FLT*

  Current cosmological cst. dens. per crit. dens.

- **-m**, **--omatter**=*FLT*

  Current matter density per critical density.

- **-O**, **--obsline**=*STR*,FLT

  Redshift from line and observed wavelength.

- **-r**, **--oradiation**=*FLT*

  Current radiation density per critical density.

- **-y**, **--velocity**=*FLT*

  Velocity of interest in km/s.

- **-z**, **--redshift**=*FLT*

  Redshift of interest.

-

  Basic cosmology calculations

- **-a**, **--absmagconv**

  Conversion to absolute magnitude (no unit).

- **-A**, **--angulardiamdist**

  Angular diameter distance (Mpc).

- **-b**, **--lookbacktime**

  Look back time to z (Ga: Giga Annum).

- **-c**, **--criticaldensity**

  Critical density at z (g/cm^3).

- **-C**, **--criticaldensitynow**

  Critical density now (g/cm^3).

- **-d**, **--properdistance**

  Proper distance to z (Mpc).

- **-e**, **--usedredshift**

  Used redshift in this run.

- **-g**, **--age**

  Age of universe at z (Ga: Giga Annum).

- **-G**, **--agenow**

  Age of universe now (Ga: Giga Annum).

- **-L**, **--luminositydist**

  Luminosity distance to z (Mpc).

- **-s**, **--arcsectandist**

  Tangential dist. for 1arcsec at z (physical kpc).

- **-u**, **--distancemodulus**

  Distance modulus at z (no units).

- **-v**, **--volume**

  Comoving volume (4pi str) to z (Mpc^3).

- **-Y**, **--usedvelocity**

  Used velocity (in km/s) for this run.

-

  Spectral lines

- **-i**, **--lineatz**=*STR*/FLT

  Wavelength of line (name or wavelength) at z.

- **--lineunit**=*STR*

  Unit ('angstrom', 'nm', 'microm' or 'm').

- **--listlines**

  List pre-defined lines at rest frame.

- **--listlinesatz**

  List pre-defined lines at the given redshift.

-

  Operating modes:

- \-?, **--help**

  give this help list

- **--checkconfig**

  List all config files and variables read.

- **--cite**

  BibTeX citation for this program.

- **--config**=*STR*

  Read configuration file STR immediately.

- **--config-prefix**=*STR*

  Custom prefix of option names config files.

- **--lastconfig**

  Do not parse any more configuration files.

- **--minmapsize**=*INT*

  Min. bytes to avoid RAM automatically.

- **--onlyversion**=*STR*

  Only run if the program version is STR.

- **-P**, **--printparams**

  Print parameter values to be used and abort.

- **--quietmmap**

  Don't print mmap'd file's name and size.

- **-S**, **--setdirconf**

  Set default values for this directory and abort.

- **--usage**

  give a short usage message

- **-U**, **--setusrconf**

  Set default values for this user and abort.

- **-V**, **--version**

  print program version

Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.

GNU Astronomy Utilities home page: http://www.gnu.org/software/gnuastro/

## REPORTING BUGS

Report bugs to bug-gnuastro@gnu.org.

## COPYRIGHT

Copyright © 2015-2024 Free Software Foundation, Inc. License GPLv3+: GNU General public license version 3 or later.\
 This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

Written/developed by Mohammad Akhlaghi

## SEE ALSO

The full documentation for **CosmicCalculator** is maintained as a Texinfo manual.  If the **info** and **CosmicCalculator** programs are properly installed at your site, the command

-

  **info CosmicCalculator**

should give you access to the complete manual.