Pixel-Based Non-Linearity Correction for the WFC3 IR Detector
Fuente:
arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866915647228739584 |
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| author | Shenoy, Sachindev S. Huynh, Ky Bajaj, Varun Mack, Jennifer |
| author_facet | Shenoy, Sachindev S. Huynh, Ky Bajaj, Varun Mack, Jennifer |
| contents | The current non-linearity correction for the Wide Field Camera 3 Infrared (WFC3/IR) channel is based on ground-based data acquired during WFC3's Thermal Vacuum 3 (TV3) testing campaign. In the current reference file, the correction coefficients derived for each pixel are averaged over each of the four detector quadrants. In this work, we compute a new pixel-based non-linearity correction using in-flight calibration observations with the internal tungsten lamp flats acquired between 2011 and 2013. We derive the new correction coefficients by fitting a third-order polynomial to the accumulated signal ``up-the-ramp" for each pixel. Approximately 2\% of IR detector pixels are flagged as bad, and a solution cannot be computed. For these, we use the quadrant averages of the new correction coefficients. An accompanying report (\cite{huynh2025}) provides detailed testing results using both internal flats and external science targets acquired in a variety of observing modes. The report highlights improvements in photometry derived from ``\_flt.fits" data products calibrated using the new reference file, with the largest improvement for pixels with fluence levels approaching the full well limit of $\sim$80,000 $e^- $. A new NLINFILE reference file was delivered in October 2025 and will be used to reprocess all WFC3/IR imaging and grism observations in the MAST archive. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_01951 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Pixel-Based Non-Linearity Correction for the WFC3 IR Detector Shenoy, Sachindev S. Huynh, Ky Bajaj, Varun Mack, Jennifer Instrumentation and Methods for Astrophysics The current non-linearity correction for the Wide Field Camera 3 Infrared (WFC3/IR) channel is based on ground-based data acquired during WFC3's Thermal Vacuum 3 (TV3) testing campaign. In the current reference file, the correction coefficients derived for each pixel are averaged over each of the four detector quadrants. In this work, we compute a new pixel-based non-linearity correction using in-flight calibration observations with the internal tungsten lamp flats acquired between 2011 and 2013. We derive the new correction coefficients by fitting a third-order polynomial to the accumulated signal ``up-the-ramp" for each pixel. Approximately 2\% of IR detector pixels are flagged as bad, and a solution cannot be computed. For these, we use the quadrant averages of the new correction coefficients. An accompanying report (\cite{huynh2025}) provides detailed testing results using both internal flats and external science targets acquired in a variety of observing modes. The report highlights improvements in photometry derived from ``\_flt.fits" data products calibrated using the new reference file, with the largest improvement for pixels with fluence levels approaching the full well limit of $\sim$80,000 $e^- $. A new NLINFILE reference file was delivered in October 2025 and will be used to reprocess all WFC3/IR imaging and grism observations in the MAST archive. |
| title | Pixel-Based Non-Linearity Correction for the WFC3 IR Detector |
| topic | Instrumentation and Methods for Astrophysics |
| url | https://arxiv.org/abs/2512.01951 |