Division B Commission 25 WG Infrared Astronomy


Kevin Volk

Space Telescope Science Institute
3700 San Martin Drive
Baltimore 21218
United States

Phone: +1 (410) 338-4409
Fax: +1 (410) 338-5090
Email 1: volkstsciedu
Email 2: kevinmichaelvolkgmailcom
Organization website: http://www.stsci.edu/~volk/

Last updated:
December 21, 2012

Group Web Page


The purpose of this working group is to promote better practices in infrared photometry. The ground-based photometry in the 1 to 2.5 micron range currently has a general precision limit of about 2.5% for stars of a wide range of brightness. The reasons why near-infrared photometry is not achieving the same sort of accuracy as optical photometry (0.5% to 0.1%) are known: the much greater effects of atmospheric extinction both at a given site and from one site to another compared to the case at optical wavelengths, a lack of standardization of the photometric passbands, lack of transformations to a standard system, and the adoption of somewhat different definitions of zero magnitude from site to site. Surprisingly, space-based photometry from WISE and Spitzer in the 3 to 5 micron wavelength range also appears to have a precision limitation around 2%. In the next decade many of the new leading astronomical facilities such as the James Webb Space Telescope and the Thirty-Metre Telescope will emphasize near-infrared observations. To obtain the best science from these facilities, the foundations of near-infrared photometry need to be improved to provide the same level of accuracy as is presently possible from ground-based optical photometry. Studies of supernovae at high redshift, of Cephied variables and other standard candles at near-infrared wavelengths, and of eclipsing binary stars for direct distance determination (to give three examples) all require better much than 2% accuracy and precision in the photometry to provide the leading-edge science that is expected from these facilities.

Group Members (13)


Division B Commission 25 Astronomical Photometry and Polarimetry

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