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James Webb Space Telescope
NIRCAM Filters

The short-wavelength channel contains 1 extra wide, 5 wide-band (R~4), 4 medium (R~10), and 3 narrow-band (R~100) filters, while the long-wavelength channel contains 1 extra wide, 3 wide, 8 medium, 4 narrow-band filters as shown in the table below. Most filters are in the filter wheels; they are typically used in combination with the CLEAR pupil wheel element. The few filters in the pupil wheels include their individual pupil stops and are paired with an appropriate blocking filter in the filter wheel.

Illustration of the NIRCam pupil wheels (left) and filter wheels (right).

NIRCam Filters:

The figure and table below show the total system throughput, henceforth referred to as Photon-to-Electron Conversion Efficiency (PCE), for all NIRCam filters. The PCE includes the effects of the JWST Optical Telescope Element (OTE), NIRCam optical train, filters, and detector QE. The Lyot stops, used for coronagraphy, cut the PCE values to 18.9% of the values shown here. For filters in the pupil wheels, the PCE also includes the effects of the appropriate blocking filter in the filter wheel. Note that throughputs of individual components, most notably the OTE, are not finalized and subject to small changes.

For all filters, these values are the mean of the module A and module B PCE. Note that there is a non-negligible difference in the detector QE between modules A and B at the longest wavelengths in the Longwave (LW) Channel. In addition, several filters, most notably F480M, show differences in throughput between the module A and module B versions. In the future, separate module A and module B calculations will be possible using synphot/pysynphot. Alternatively, the separate module A/module B curves (as well as the module-average curves) are present in the tarball and zip files which can be downloaded below.

Plot showing the NIRCam filters bandpasses. The vertical bar indicates the beamsplitter dead band; 'P' indicates the filters mounted in the pupil wheels. Values are (filter x detector QE x NIRCam optics x OTE).

Click filter name in the table below to download a copy of the PCE table (W2=Extra Wide, W=Wide, M=Medium, N=Narrow). Values below represent version 4.0 of the PCE curves, and are current as of 22 April 2016. Module-specific and module-averaged PCE values can be obtained by downloading the tar file or zipped folder of all filters from the top row of the table below. These files contain all PCE files, as well as additional plots, and a copy of the table below in a text file.

Filter
(module-average)
Use
Pivot1
Wavelength
(microns)
Bandwidth2
(microns)
BW/Pivot
%
Effective3
Response
Blue Side
Half-Power4
Wavelength (microns)
Red Side
Half-Power4
Wavelength (microns)
Download all filters: (tar.gz) (zip)
SW Channel
F150W2F162M, F164N, and DHS Blocking Filter1.6591.17570.80.4151.0082.334
F070WGeneral Purpose 0.7040.13218.80.2000.6210.781
F090WGeneral Purpose 0.9020.19421.50.2920.7951.005
F115WGeneral Purpose 1.1540.22519.50.3251.0131.282
F150WGeneral Purpose 1.5010.31821.20.4221.3311.668
F200WGeneral Purpose 1.9890.45723.00.4721.7552.226
F140MCool Stars, H2O, CH4 1.4050.14210.10.3971.3311.479
F162MCool Stars, Off-band for H2O 1.6270.16810.30.4161.5421.713
F182MCool Stars, H2O, CH4 1.8450.23712.90.4541.7221.968
F210MH2O, CH4 2.0950.2069.80.4611.9922.201
F164N[FeII] 1.6450.0201.20.3551.6351.653
F187NPa-alpha 1.8740.0241.30.3741.8631.884
F212NH2 2.1210.0271.30.3942.1092.134
Filter
(module-average)
Use
Pivot1
Wavelength
(microns)
Bandwidth2
(microns)
BW/Pivot
%
Effective3
Response
Blue Side
Half-Power4
Wavelength (microns)
Red Side
Half-Power4
Wavelength (microns)
LW Channel
F322W2 Background Min. Primarily used with grisms. Blocking filter for F323N. 3.2321.35642.00.4432.4304.013
F277W General Purpose 2.7620.68324.70.3892.4163.127
F356W General Purpose 3.5680.78121.90.4803.1403.980
F444W General Purpose. Blocking filter for F405N, F466N, F470N. 4.4081.02923.30.4743.8804.986
F250M CH4, Continuum 2.5030.1807.20.3832.4122.595
F300M Water Ice 2.9890.31510.50.3632.8293.155
F335M PAH, CH4 3.3620.35210.50.4173.1773.538
F360M Brown Dwarfs, Planets, Continuum 3.6240.37010.20.4583.4273.814
F410M Brown Dwarfs, Planets, H2O, CH4 4.0820.43810.70.4693.8644.301
F430M CO2, N2 4.2810.2285.30.4694.1674.398
F460M CO 4.6300.2294.90.3924.5154.747
F480M Brown Dwarfs, Planets, Continuum 4.8740.3006.10.3174.6624.977
F323N H2 3.2370.0381.20.2853.2173.255
F405N Br-alpha 4.0520.0451.10.3724.0284.074
F466N CO 4.6540.0541.20.2934.6294.681
F470N H2 4.7080.0511.10.2744.6834.733

1 - The pivot wavelength satisfies the equation below, relating the flux measured in wavelength versus frequency units.
F_{\nu} = F_{\lambda} \lambda_{pivot}^2 / c
where
F_{\nu}d\nu = F_{\lambda}d\lambda
To calculate the pivot wavelength, we perform the following integration:
\lambda_{pivot} = \sqrt[]{\frac{\int \lambda PCE(\lambda) \,d\lambda}{\int (PCE(\lambda)/\lambda) d\lambda}}
     See Tokunaga, A. T., & Vacca, W. D., 2005 PASP 117, 421.

2 - Bandwidth is the integral of the normalized PCE curve. See equation 1 in appendix E of Rieke, G. H., Blaylock, M., Decin, L., et al. 2008, AJ, 135, 2245.
BW = \frac{1}{PCE_{max}}\int PCE(\lambda) \,d\lambda

3 - Effective Response is the mean PCE value over the wavelength range of λpivot +/- (0.5 * BW)

4 - The half power wavelengths of a passband are the wavelengths at which the PCE falls to 50% of its peak value.