The James Webb Space Telescope Absolute Flux Calibration. VI. Near-infrared Camera Imaging and Coronagraphy
- 1Space Telescope Science Institute
Abstract
We present an updated flux calibration for all imaging modes of the Near Infrared Camera (NIRCam) on JWST that converts instrumental units to physical surface brightness units of MJy sr ⁻¹ . This calibration includes observations of 19 flux standard stars spanning 3.5 yr, with a mix of A dwarfs, solar analogs, and hot stars. All five coronagraphic setups, all 29 filters, and both weak lenses are calibrated. This is the first on-sky calibration for the weak lenses used in time-series observations and for secondary coronagraphic configurations (long-wavelength masks paired with short-wavelength filters, and vice versa). We also assess count-rate differences between subarrays and the full frame, finding differences of up to ∼1%. These differences are incorporated into the calibration factors. We find that the scatter in the calibration factor is typically <2%, with about half of the filter+detector[+mask] combinations reaching <1% scatter. There are no trends with detector effects such as the count rate and well depth. Images in a handful of filters of the Large Magellanic Cloud and globular cluster 47 Tuc show that residual detector-to-detector offsets are typically small (<1%), but can be as high as 4%–5%. The NIRCam detectors are found to be quite stable, with possible count-rate decreases of <0.4% per year, which is within the calibration uncertainties. These new calibration factors were incorporated into the JWST pipeline in 2026 March.
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BibTeX
@article{boyer2026james,
title = {{The James Webb Space Telescope Absolute Flux Calibration. VI. Near-infrared Camera Imaging and Coronagraphy}},
author = {Martha L. Boyer and Benjamin Sunnquist and Bryan Hilbert and Dan Coe and Varun Bajaj and Paul Bennet and Julien H. Girard},
journal = {The Astronomical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-3881/aea6b4},
url = {https://iopscience.iop.org/article/10.3847/1538-3881/aea6b4},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The James Webb Space Telescope Absolute Flux Calibration. VI. Near-infrared Camera Imaging and Coronagraphy
AU - Martha L. Boyer
AU - Benjamin Sunnquist
AU - Bryan Hilbert
AU - Dan Coe
AU - Varun Bajaj
AU - Paul Bennet
AU - Julien H. Girard
PY - 2026
DA - 2026/10/08
JO - The Astronomical Journal
DO - 10.3847/1538-3881/aea6b4
UR - https://iopscience.iop.org/article/10.3847/1538-3881/aea6b4
AB - We present an updated flux calibration for all imaging modes of the Near Infrared Camera (NIRCam) on JWST that converts instrumental units to physical surface brightness units of MJy sr ⁻¹ . This calibration includes observations of 19 flux standard stars spanning 3.5 yr, with a mix of A dwarfs, solar analogs, and hot stars. All five coronagraphic setups, all 29 filters, and both weak lenses are calibrated. This is the first on-sky calibration for the weak lenses used in time-series observations and for secondary coronagraphic configurations (long-wavelength masks paired with short-wavelength filters, and vice versa). We also assess count-rate differences between subarrays and the full frame, finding differences of up to ∼1%. These differences are incorporated into the calibration factors. We find that the scatter in the calibration factor is typically <2%, with about half of the filter+detector[+mask] combinations reaching <1% scatter. There are no trends with detector effects such as the count rate and well depth. Images in a handful of filters of the Large Magellanic Cloud and globular cluster 47 Tuc show that residual detector-to-detector offsets are typically small (<1%), but can be as high as 4%–5%. The NIRCam detectors are found to be quite stable, with possible count-rate decreases of <0.4% per year, which is within the calibration uncertainties. These new calibration factors were incorporated into the JWST pipeline in 2026 March.
SN - 0004-6256
SN - 1538-3881
ER -