## GNU Astronomy Utilities

#### 9.1.3.1 CosmicCalculator input options

The inputs to CosmicCalculator can be specified with the following options:

-z FLT
--redshift=FLT

The redshift of interest. There are two other ways that you can specify the target redshift: 1) Spectral lines and their observed wavelengths, see --obsline. 2) Velocity, see --velocity. Hence this option cannot be called with --obsline or --velocity.

-y FLT
--velocity=FLT

Input velocity in km/s. The given value will be converted to redshift internally, and used in any subsequent calculation. This option is thus an alternative to --redshift or --obsline, it cannot be used with them. The conversion will be done with the more general and accurate relativistic equation of $$1+z=\sqrt{(c+v)/(c-v)}$$, not the simplified $$z\approx v/c$$.

-H FLT
--H0=FLT

Current expansion rate (in km sec$$^{-1}$$ Mpc$$^{-1}$$).

-l FLT
--olambda=FLT

Cosmological constant density divided by the critical density in the current Universe ($$\Omega_{\Lambda,0}$$).

-m FLT
--omatter=FLT

Matter (including massive neutrinos) density divided by the critical density in the current Universe ($$\Omega_{m,0}$$).

-r FLT
--oradiation=FLT

Radiation density divided by the critical density in the current Universe ($$\Omega_{r,0}$$).

-O STR/FLT,FLT
--obsline=STR/FLT,FLT

Find the redshift to use in next steps based on the rest-frame and observed wavelengths of a line. This option is thus an alternative to --redshift or --velocity, it cannot be used with them. Wavelengths are assumed to be in Angstroms. The first argument identifies the line. It can be one of the standard names below, or any rest-frame wavelength in Angstroms. The second argument is the observed wavelength of that line. for example, --obsline=lyalpha,6000 is the same as --obsline=1215.64,6000.

The pre-defined names are listed below, sorted from red (longer wavelength) to blue (shorter wavelength). You can get this list on the command-line with the --listlines.

siired

[6731Å] SII doublet’s redder line.

sii

[6724Å] SII doublet’s mean center at .

siiblue

[6717Å] SII doublet’s bluer line.

niired

[6584Å] NII doublet’s redder line.

nii

[6566Å] NII doublet’s mean center.

halpha

[6562.8Å] H-$$\alpha$$ line.

niiblue

[6548Å] NII doublet’s bluer line.

oiiired-vis

[5007Å] OIII doublet’s redder line in the visible.

oiii-vis

[4983Å] OIII doublet’s mean center in the visible.

oiiiblue-vis

[4959Å] OIII doublet’s bluer line in the visible.

hbeta

[4861.36Å] H-$$\beta$$ line.

heii-vis

[4686Å] HeII doublet’s redder line in the visible.

hgamma

[4340.46Å] H-$$\gamma$$ line.

hdelta

[4101.74Å] H-$$\delta$$ line.

hepsilon

[3970.07Å] H-$$\epsilon$$ line.

neiii

[3869Å] NEIII line.

oiired

[3729Å] OII doublet’s redder line.

oii

[3727.5Å] OII doublet’s mean center.

oiiblue

[3726Å] OII doublet’s bluer line.

blimit

[3646Å] Balmer limit.

mgiired

[2803Å] MgII doublet’s redder line.

mgii

[2799.5Å] MgII doublet’s mean center.

mgiiblue

[2796Å] MgII doublet’s bluer line.

ciiired

[1909Å] CIII doublet’s redder line.

ciii

[1908Å] CIII doublet’s mean center.

ciiiblue

[1907Å] CIII doublet’s bluer line.

si_iiired

[1892Å] SiIII doublet’s redder line.

si_iii

[1887.5Å] SiIII doublet’s mean center.

si_iiiblue

[1883Å] SiIII doublet’s bluer line.

oiiired-uv

[1666Å] OIII doublet’s redder line in the ultra-violet.

oiii-uv

[1663.5Å] OIII doublet’s mean center in the ultra-violet.

oiiiblue-uv

[1661Å] OIII doublet’s bluer line in the ultra-violet.

heii-uv

[1640Å] HeII doublet’s bluer line in the ultra-violet.

civred

[1551Å] CIV doublet’s redder line.

civ

[1549Å] CIV doublet’s mean center.

civblue

[1548Å] CIV doublet’s bluer line.

nv

[1240Å] NV (four times ionized Sodium).

lyalpha

[1215.67Å] Lyman-$$\alpha$$ line.

lybeta

[1025.7Å] Lyman-$$\beta$$ line.

lygamma

[972.54Å] Lyman-$$\gamma$$ line.

lydelta

[949.74Å] Lyman-$$\delta$$ line.

lyepsilon

[937.80Å] Lyman-$$\epsilon$$ line.

lylimit

[912Å] Lyman limit.