NED is providing these links to outside sites at the specific request of users and as an additional service to extragalactic researchers in general. The NED Team has not fully validated any of these calculators, and questions concerning the algorithms used, their range of application and the precision of the returned results should be directed to the original Web site creators.

Cosmology Calculator I

Ned Wright, UCLA

This calculator allows one to input user-selected values of the Hubble constant, Omega(matter), Omega(vacuum) and the redshift z, and returns the current age of the Universe, the age, the co-moving radial distance (and volume) and the angular-size distance at the specified redshift, as well as the scale (kpc/arcsec) and the luminosity distance.

Curator's email address:

Cosmology Calculator II

Nick Gnedin, University of Colorado

This calculator accepts Omega(total), a value of the Hubble constant, plus either a redshift or a scale factor, and it computes: (1) the age and lookback time, (2) the past and future horizon distances, (3) the angular size for a given physical size (and vice versa), (4) the angular distance, (5) the Hubble parameter at the given redshift, and (5) the distance between two input redshifts. Physical scale units can be in either parsecs or lightyears.

Curator's email address:

Cosmology Calculator III

Chip Kobulnicky, University of Wyoming

This calculator allows one to input a redshift (or a list of up to 20 redshifts), the Hubble constant, Omega(matter), Omega(Lambda) and a luminosity, returning the age of the Universe at redshift z, the look-back time to redshift z, the angular scale, the surface brightness factor, the observed flux, the effective distance modulus and the K-correction (band-pass term only).

Curator's email address:

Cosmology Calculator IV: CosmoTools

Alberto Cappi, Bologna

This simple program calculates luminosity and co-moving distances from a user-specified redshift, deceleration parameter and Hubble constant. Presently the calculator uses only the standard Friedmann-Lemaitre (i.e., Lambda = 0) cosmological models.

Curator's email address:

K-Correction Calculators

Ultraviolet to Near-Infrared K-corrections calculator

This service provides analytical approximations of K-corrections applicable to quiescent ("red and dead"), star-forming, and starburst galaxies (non-AGNs) with z < 0.5. The photometric bands covered include GALEX FUV/NUV, SDSS ugriz, Johnson/Cousins UBVRI, UKIRT YJHK, and 2MASS JHKs.

See Chilingarian & Zolotukhin 2012, MNRAS, 419, 1727.

K-corrections at X-ray energies using Sherpa

The calc_kcorr function in the Sherpa data analysis package can be used to calculate K-corrections for various spectral models at X-ray energies.