PHANGS-JWST: Data Processing Pipeline and First Full Public Data Release (2401.15142v3)

Abstract: The exquisite angular resolution and sensitivity of JWST is opening a new window for our understanding of the Universe. In nearby galaxies, JWST observations are revolutionizing our understanding of the first phases of star formation and the dusty interstellar medium. Nineteen local galaxies spanning a range of properties and morphologies across the star-forming main sequence have been observed as part of the PHANGS-JWST Cycle 1 Treasury program at spatial scales of $\sim$5-50pc. Here, we describe pjpipe, an image processing pipeline developed for the PHANGS-JWST program that wraps around and extends the official JWST pipeline. We release this pipeline to the community as it contains a number of tools generally useful for JWST NIRCam and MIRI observations. Particularly for extended sources, pjpipe products provide significant improvements over mosaics from the MAST archive in terms of removing instrumental noise in NIRCam data, background flux matching, and calibration of relative and absolute astrometry. We show that slightly smoothing F2100W MIRI data to 0.9" (degrading the resolution by about 30 percent) reduces the noise by a factor of $\approx$3. We also present the first public release (DR1.1.0) of the pjpipe processed eight-band 2-21 $\mu$m imaging for all nineteen galaxies in the PHANGS-JWST Cycle 1 Treasury program. An additional 55 galaxies will soon follow from a new PHANGS-JWST Cycle 2 Treasury program.

• The paper details a tailored image processing pipeline for PHANGS-JWST, improving noise reduction and astrometric calibration for multi-band galaxy imaging.
• The methodology incorporates bespoke tools to handle 1/f noise, robust background matching, and enhanced mosaicking of JWST data across varied galactic fields.
• The public release of eight-band imaging data for 19 local galaxies accelerates research into star formation and the properties of the dusty interstellar medium.

PHANGS-JWST: Data Processing Pipeline and First Full Public Data Release

The paper "PHANGS-JWST: Data Processing Pipeline and First Full Public Data Release" presents a comprehensive overview of the data processing methodologies employed for imaging data from the Physics at High Angular resolution in Nearby GalaxieS using the James Webb Space Telescope (PHANGS-JWST) Cycle 1 Treasury program. The focus of this program is on observing nineteen local galaxies with diverse properties across the star-forming main sequence, achieving spatial scales of approximately 5–50 parsecs. The data is crucial for probing early star formation stages and the dusty interstellar medium (ISM) within these galaxies.

Key Elements of the Data Processing Pipeline

1. Pipeline Development: The paper describes the development and architecture of an image processing pipeline specifically designed for PHANGS-JWST. This pipeline augments the existing JWST pipeline by incorporating specialized tools for Near Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) observations. A significant aim is to achieve better handling of instrumental noise, background flux matching, and calibration of astrometry compared to standard pipeline products available through the Mikulski Archive for Space Telescopes (MAST).
2. Bespoke Processing Techniques: Notable modifications include handling $1/f$ noise in NIRCam data, implementing robust background matching to suppress instrumental artifacts, and optimizing astrometric alignment to ensure coherent mosaicking of large galaxy fields observed in multiple tiles and bands. These improvements facilitate better handling of data where emission fills the field and background reference frames might otherwise be inadequate.
3. Noise Reduction and Calibration: The pipeline includes methods for reducing noise through Gaussian smoothing, notably in the MIRI data where the pixel size significantly oversamples the point spread function (PSF), thereby enhancing the signal-to-noise ratio without severely degrading spatial resolution.
4. First Data Release and Results: The pipeline's products improve upon MAST's mosaics regarding instrumental noise and background matching. The release (DR1.1.0) provides eight-band imaging for the observed galaxies, adhering to the pipeline’s improved processing standards. The pipeline and its configurations are accessible for broader community use, promoting transparency and reproducibility.
5. Science Implications and Pipeline Utility: The presented pipeline facilitates studies into galaxy-wide processes governing star formation and feedback mechanisms in these systems. Its robustness and generalized implementations allow applicability beyond the immediate science goals of PHANGS-JWST, extending potential usage across varied astrophysical datasets acquired with JWST.

Potential Future Developments

Future endeavors will likely focus on further refining the pipeline processes, incorporating advancements in JWST’s post-commissioning calibration data, and enhancing the accuracy of astrometric alignment. Additionally, there's potential for adapting algorithms optimized by this pipeline for other high-resolution astrophysical surveys, particularly those concerning galactic structure and formation processes.

In conclusion, the PHANGS-JWST pipeline represents a significant advancement in processing JWST imaging data for detailed studies of nearby galaxies. The paper underscores the substantial gains achievable in data fidelity through tailored algorithmic developments while setting a standard for future releases and community collaborations in galactic astrophysical research.