Recalibrating the Wide-field Infrared Survey Explorer (WISE) W4 Filter. (22nd December 2014)

• Record Type: Journal Article
• Authors: Brown, M. J. I.; Jarrett, T. H.; Cluver, M. E.
• Is Part Of: Publications of the Astronomical Society of Australia. Volume 31(2014)
• Page Start: 18
• Publication Date: 2014-12-22
• Subjects: Astronomy -- Periodicals; Southern sky (Astronomy) -- Periodicals; Astrophysics -- Periodicals; Periodicals; 520.5
• DOI: 10.1017/pasa.2014.44
• Languages: English
• ISSNs: 1323-3580

Abstract

<abstract abstract-type="normal"> <title>Abstract</title> <p>We present a revised effective wavelength and photometric calibration for the <italic>Wide-field Infrared Survey Explorer W</italic>4 band, including tests of empirically motivated modifications to its pre-launch laboratory-measured relative system response curve. We derived these by comparing measured <italic>W</italic>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 <italic>W</italic>4 relative system response can be as large as 0.3 mag for galaxies and 1 mag for planetary nebulae. We find the <italic>W</italic>4 effective wavelength should be revised upward by 3.3%, from 22.1 to 22.8 μm, and the <italic>W</italic>4 AB magnitude of Vega should be revised from <italic>m</italic><sub><italic>W</italic>4</sub> = 6.59 to <italic>m</italic><sub><italic>W</italic>4</sub> = 6.66. In an attempt to reproduce the observed <italic>W</italic>4 photometry, we tested three modifications to the pre-launch laboratory-measured <italic>W</italic>4 relative system response curve, all of which have an effective wavelength of 22.8 μm. 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 ≃ 0.73 μm) achieves reasonable agreement between the measured and synthesised photometry.</p> </abstract>