Abstract
We present the Local Group L-Band Survey, a Karl G. Jansky Very Large Array (VLA) survey producing the highest-quality 21 cm and 1-2 GHz radio continuum images to date, for the six VLA-accessible, star-forming, Local Group galaxies. Leveraging the VLA’s spectral multiplexing power, we simultaneously survey the 21 cm line at high 0.4 km s−1 velocity resolution, the 1-2 GHz polarized continuum, and four OH lines. For the massive spiral M31, the dwarf spiral M33, and the dwarf irregular galaxies NGC 6822, IC 10, IC 1613, and the Wolf-Lundmark-Melotte Galaxy, we use all four VLA configurations and the Green Bank Telescope to reach angular resolutions of <5″ (10-20 pc) for the 21 cm line with <1020 cm−2 column density sensitivity, and even sharper views (<2″; 5-10 pc) of the continuum. Targeting these nearby galaxies (D ≲ 1 Mpc) reveals a sharp, resolved view of the atomic gas, including 21 cm absorption, and continuum emission from supernova remnants and H ii regions. These data sets can be used to test theories of the abundance and formation of cold clouds, the driving and dissipation of interstellar turbulence, and the impact of feedback from massive stars and supernovae. Here, we describe the survey design and execution, scientific motivation, data processing, and quality assurance. We provide a first look at and publicly release the wide-field 21 cm H i data products for M31, M33, and four dwarf irregular targets in the survey, which represent some of the highest-physical-resolution 21 cm observations of any external galaxies beyond the LMC and SMC.
| Original language | English |
|---|---|
| Article number | 35 |
| Journal | Astrophysical Journal, Supplement Series |
| Volume | 279 |
| Issue number | 2 |
| DOIs | |
| State | Published - Aug 1 2025 |
Bibliographical note
Publisher Copyright:© 2025. The Author(s). Published by the American Astronomical Society.
Funding
We gratefully acknowledge the anonymous reviewer for providing comments that improved the clarity of this paper. We are grateful for the support of the staff at the National Radio Astronomy Observatory who facilitated this “Extra Large” program. Our survey design benefited from an extensive technical review led by Claire Chandler, and we are grateful for the work of the VLA scheduling team, especially Amy Mioduszewski, for helping facilitate our observational requirements. We thank Filippo Maccagni for sharing his compilation of archival H i surveys that we reproduce in Figure . The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research was enabled in part by support provided by the Digital Research Alliance of Canada ( alliancecan.ca ). This research used the Canadian Advanced Network For Astronomy Research (CANFAR) operated in partnership by the Canadian Astronomy Data Centre and The Digital Research Alliance of Canada with support from the National Research Council of Canada the Canadian Space Agency, CANARIE, and the Canadian Foundation for Innovation. Some of the computations in this paper were conducted on the Smithsonian High Performance Cluster (SI/HPC), Smithsonian Institution ( https://doi.org/10.25572/SIHPC ). The LGLBS collaboration is grateful for support from the National Science Foundation, AST-2205628 and AST-205630. E.W.K. acknowledges support from the Smithsonian Institution as a Submillimeter Array (SMA) Fellow and the Natural Sciences and Engineering Research Council of Canada. L.C. also acknowledges support from NSF grant AST-2107070. E.R. and H.C. acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference No. RGPIN-2022-03499. T.W. gratefully acknowledges support from the Chu Family Foundation for the Vermilion River Fund for Astronomical Research at the University of Illinois. S.S. gratefully acknowledges support provided by the University of Wisconsin - Madison Office of the Vice Chancellor for Research and Graduate Education with funding from the Wisconsin Alumni Research Foundation. D.J.P. is supported through the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation (grant No. 77825). J.S. acknowledges support by the National Aeronautics and Space Administration (NASA) through the NASA Hubble Fellowship grant HST-HF2-51544 awarded by the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS 5-26555.
| Funders | Funder number |
|---|---|
| Wisconsin Alumni Research Foundation | |
| Department of Science and Technology, Republic of South Africa | |
| Smithsonian Institution | |
| Canada Foundation for Innovation | |
| Canarie | |
| Canadian Advanced Network for Astronomy Research | |
| Office of the Vice Chancellor for Research and Graduate Education, University of Wisconsin-Madison | |
| Canadian Space Agency | |
| Natural Sciences and Engineering Research Council of Canada | |
| Chu Family Foundation | |
| National Research Council Canada (NRCC) | |
| Alliance de recherche numérique du Canada | |
| National Science Foundation Arctic Social Science Program | AST-2107070, AST-205630, RGPIN-2022-03499, AST-2205628 |
| National Research Foundation South African Research Chair | 77825 |
| Space Telescope Science Institute | NAS 5-26555 |
| National Aeronautics and Space Administration | HST-HF2-51544 |
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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