We present a revised effective wavelength and photometric calibration for the Wide-field Infrared Survey Explorer ( WISE ) W 4 band , including tests of empirically motivated modifications to its pre-launch laboratory-measured relative system response curve .
We derived these by comparing measured W 4 photometry with photometry synthesised from spectra of galaxies and planetary nebulae .
The difference between measured and synthesised photometry using the pre-launch laboratory-measured W 4 relative system response can be as large as 0.3 ~ { } { mag } for galaxies and 1 ~ { } { mag } for planetary nebulae .
We find the W 4 effective wavelength should be revised upward by 3.3 % , from 22.1 ~ { } { \mu m } to 22.8 ~ { } { \mu m } , and the W 4 AB magnitude of Vega should be revised from m _ { W 4 } = 6.59 to m _ { W 4 } = 6.66 .
In an attempt to reproduce the observed W 4 photometry , we tested three modifications to the pre-launch laboratory-measured W 4 relative system response curve , all of which have an effective wavelength of 22.8 ~ { } { \mu m } .
Of the three relative system response curve models tested , a model that matches the laboratory-measured relative system response curve , but has the wavelengths increased by 3.3 % ( or \simeq 0.73 ~ { } { \mu m } ) achieves reasonable agreement between the measured and synthesised photometry .