HETDEX-LOFAR Spectroscopic Redshift Catalog

Debski, Maya H.; Zeimann, Gregory R.; Hill, Gary J.; Schneider, Donald P.; Morabito, Leah; Dalton, Gavin; Jarvis, Matt J.; Mentuch Cooper, Erin; Ciardullo, Robin; Gawiser, Eric; Jurlin, Nika

Abstract

We combine the power of blind integral field spectroscopy from the Hobby–Eberly Telescope (HET) Dark Energy Experiment (HETDEX) with sources detected by the Low Frequency Array (LOFAR) to construct the HETDEX-LOFAR Spectroscopic Redshift Catalog. Starting from the first data release of the LOFAR Two-metre Sky Survey, including a value-added catalog with photometric redshifts, we extracted 28,705 HETDEX spectra. Using an automatic classifying algorithm, we assigned each object a star, galaxy, or quasar label along with a velocity/redshift, with supplemental classifications coming from the continuum and emission-line catalogs of the internal, fourth data release from HETDEX (HDR4). We measured 9087 new redshifts; in combination with the value-added catalog, our final spectroscopic redshift sample is 9710 sources. This new catalog contains the highest substantial fraction of LOFAR galaxies with spectroscopic redshift information; it improves archival spectroscopic redshifts and facilitates research to determine the [O ii] emission properties of radio galaxies from 0.0 < z < 0.5, and the Lyα emission characteristics of both radio galaxies and quasars from 1.9 < z < 3.5. Additionally, by combining the unique properties of LOFAR and HETDEX, we are able to measure star formation rates (SFRs) and stellar masses. Using the Visible Integral-field Replicable Unit Spectrograph, we measure the emission lines of [O iii], [Ne iii], and [O ii] and evaluate line-ratio diagnostics to determine whether the emission from these galaxies is dominated by active galactic nuclei or star formation and fit a new SFR–L 150MHz relationship.

Citation

Debski, M. H., Zeimann, G. R., Hill, G. J., Schneider, D. P., Morabito, L., Dalton, G., Jarvis, M. J., Mentuch Cooper, E., Ciardullo, R., Gawiser, E., & Jurlin, N. (2025). HETDEX-LOFAR Spectroscopic Redshift Catalog. The Astrophysical Journal, 978(1), Article 101. https://doi.org/10.3847/1538-4357/ad957b

• Journal Article Type: Article
• Acceptance Date: Nov 18, 2024
• Online Publication Date: Dec 27, 2024
• Publication Date: Jan 1, 2025
• Deposit Date: Jan 17, 2025
• Publicly Available Date: Jan 17, 2025
• Journal: The Astrophysical Journal
• Electronic ISSN: 1538-4357
• Peer Reviewed: Peer Reviewed
• Volume: 978
• Issue: 1
• Article Number: 101
• DOI: https://doi.org/10.3847/1538-4357/ad957b
• Keywords: Redshift surveys, Radio continuum emission, Radio active galactic nuclei, Galaxy evolution
• Public URL: https://durham-repository.worktribe.com/output/3230119