JADES Data Release 3 -- NIRSpec/MSA spectroscopy for 4,000 galaxies in the GOODS fields (2404.06531v1)

Abstract: We present the third data release of JADES, the JWST Advanced Deep Extragalactic Survey, providing both imaging and spectroscopy in the two GOODS fields. Spectroscopy consists of medium-depth and deep NIRSpec/MSA spectra of 4,000 targets, covering the spectral range 0.6-5.3 $\mu$m and observed with both the low-dispersion prism (R=30-300) and all three medium-resolution gratings (R=500-1,500). We describe the observations, data reduction, sample selection, and target allocation. We measured 2,375 redshifts (2,053 from multiple emission lines); our targets span the range from z=0.5 up to z=13, including 404 at z>5. The data release includes 2-d and 1-d fully reduced spectra, with slit-loss corrections and background subtraction optimized for point sources. We also provide redshifts and S/N>5 emission-line flux catalogs for the prism and grating spectra, and concise guidelines on how to use these data products. Alongside spectroscopy, we are also publishing fully calibrated NIRCam imaging, which enables studying the JADES sample with the combined power of imaging and spectroscopy. Together, these data provide the largest statistical sample to date to characterize the properties of galaxy populations in the first billion years after the Big Bang.

• The paper presents the third JADES data release, featuring NIRSpec/MSA spectroscopy for approximately 4,000 galaxies in the GOODS fields, providing the largest statistical sample for studying early universe galaxies.
• The release includes high-quality spectral data across redshifts 0.5-13 with a high spectroscopic redshift success rate (2,375 confirmed), enabling detailed analysis of galaxy properties.
• While offering unprecedented data for understanding galaxy evolution and cosmic dawn, the release also highlights calibration challenges like wavelength discrepancies and flux mismatches between different instrument dispersers.

An Essay on "JADES Data Release 3 -- NIRSpec/MSA Spectroscopy for 4,000 Galaxies in the GOODS Fields"

The JADES Data Release 3 presents a substantial advancement in our understanding of the early universe through the comprehensive dataset acquired from the James Webb Space Telescope (JWST). This release is a product of the JWST Advanced Deep Extragalactic Survey (JADES) and includes both imaging and spectroscopy of approximately 4,000 galaxies in the GOODS fields, specifically utilizing the Near Infrared Spectrograph (NIRSpec) instrument with its Multi Shutter Assembly (MSA).

Highlights of the Data Release

The dataset is noteworthy for several reasons. First, it covers an extensive range of redshifts, from 0.5 to as high as 13, providing insights into galaxies' formation and evolution across most of the observable universe's history. The data span the spectral range from 0.6 to 5.3 microns and were collected using both the low-dispersion prism and all three medium-resolution gratings, which allows for a detailed analysis of the physical conditions in these galaxies.

Particularly remarkable is the high success rate in determining spectroscopic redshifts, with 2,375 confirmed redshifts, of which 2,053 are based on multiple emission lines, reaffirming the reliability and precision of the selected methodologies. The dataset includes fully reduced two-dimensional and one-dimensional spectra, optimized for point sources with necessary slit-loss corrections and background subtraction.

Methodological and Instrumental Achievements

The sheer volume of data processed in this release illustrates the successful deployment of JWST’s NIRSpec/MSA, showcasing its efficacy as a high-multiplicity, slit-based near-infrared spectrograph. The spectra’s high signal-to-noise ratios and the ability to measure redshifts in galaxies that are extremely distant or faint exemplify the instrumental strengths.

JADES leverages the synergy between photometry from JWST's Near Infrared Camera (NIRCam) and NIRSpec spectroscopy. In releasing these data, the survey has provided the largest statistical sample to date for studying galaxy populations in the early universe, particularly those within the first billion years following the Big Bang.

Challenges and Calibration Insights

While the dataset offers numerous opportunities, it also highlights calibration challenges. Despite efforts at comprehensive data reduction, there remain issues relating to wavelength calibration discrepancies among different dispersers – an average offset in redshifts derived from the prism relative to the medium-resolution gratings has been observed. Furthermore, the analysis revealed flux calibration mismatches contingent on wavelength, necessitating user awareness when utilizing emission line ratios from different dispersers.

Another significant challenge involves accounting for extended galaxy structures, as the current reduction methods optimize point-source correction, potentially biasing flux measurements for extended sources.

Implications and Future Prospects

Practically, the release propels us toward a more nuanced understanding of galaxy evolution, composition, and behavior throughout cosmic time, offering invaluable data for the community engaged in high-redshift space studies. The proven methodologies and strategies adopted here offer a template for future surveys, ensuring a continuous increase in data precision and accuracy.

In a theoretical context, the insights gathered here could significantly refine models of galaxy formation and evolution, challenging existing paradigms and inspiring new hypotheses. The detected broad redshift range and the accompanying spectral data present opportunities to dissect the chemical composition, star-formation rates, and other intrinsic properties of early galaxies, enhancing our comprehension of cosmic dawn.

Conclusion

In conclusion, the third JADES data release stands as a testament to the continuing power of astronomical instrumentation and data analysis in unveiling the mysteries of the universe. Beyond its immediate contributions, it sets the stage for further developments in spectroscopic techniques and JWST’s continuing exploration and lends crucial empirical support for theoretical models of early galaxy evolution. This release not only advances our understanding of the early universe but also scaffolds future explorations and discoveries in the field of exoplanetary and galactic astrophysics.