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Photometric zero points

 

Photometric zero points

 

Imaging throughput for NIRI is tabulated in the form of photometric zero points for JHK bands. Zero points are given by

mstd = mzero - 2.5 log (N/t) - k (μ -1)

where N is the background-subtracted number of ADU within the aperture, t is the exposure time, μ is the airmass. Extinction coefficients were taken from Leggett et al. (2006). Magnitudes were measured within an aperture that is equal to 4 times the FWHM of the images, so they are insensitive to seeing variations. Non-linearity effects are not taken into account, and they may introduce zero point errors at the 10% level.  Zero points are currently only provided for F6 and F32 cameras. Further calibrations will be performed for the F14 camera, and will be made available soon.  For more details, please consult Gemini's NIR photometric standard stars page.  For the data, follow the links in the table below:

 

 Camera  Band

  Individual

 Measurements 

Monthly

Averages 

Plot 
 F/32  J Table  Table   Click  
 F/32  H Table  Table   Click  
 F/32  K Table Table   Click  
 F/32  all - -  Click  
 F/6 Y Table  Table   Click  
 F/6 J Table  Table   Click  
 F/6 H Table  Table   Click  
 F/6 Table  Table   Click  
 F/6 all  Click