Analytical approximations of K-corrections in optical and near-infrared bands

Understand

To compare photometric properties of galaxies at different redshifts, the fluxes need to be corrected for the changes of effective rest-frame wavelengths of filter bandpasses, called K-corrections.

• Usual approaches to compute them are based on the template fitting of observed spectral energy distributions (SED) and, thus, require multi-colour photometry.
• Here, we demonstrate that, in cases of widely used optical and near-infrared filters, K-corrections can be precisely approximated as two-dimensional low-order polynomials of only two parameters: redshift and one observed colour.
• With this minimalist approach, we present the polynomial fitting functions for K-corrections in SDSS ugriz, UKIRT WFCAM YJHK, Johnson-Cousins UBVR_cI_c, and 2MASS JHK_s bands for galaxies at redshifts Z<0.5 based on empirically-computed values obtained by fitting combined optical-NIR SEDs of a set of 10^5 galaxies constructed from SDSS DR7 and UKIDSS DR5 photometry using the Virtual Observatory.