LOFAR follow-up of sources in the First LHAASO Catalogue
Abstract
The First LHAASO Catalogue lists 90 sources of very-high-energy gamma-ray emission, many without an established counterpart at other frequencies, reopening the question of which Galactic accelerators produce the highest-energy cosmic rays. We search for low-frequency radio counterparts to the 55 1LHAASO sources that fall within the Galactic fields of the LOFAR Two-metre Sky Survey Data Release Three (LoTSS-DR3), using 144~MHz continuum maps at 6'' and 20'' resolution, complemented with archival data from other radio surveys where available. We present an overview of the radio emission towards all 55 sources, and identify the structures potentially associated with the gamma-ray emission. We report 24 new supernova remnant (SNR) candidates, nine flat-spectrum radio shells with faint or no infrared counterpart, and six sources with no clear Galactic radio emission present in the LOFAR maps. A bootstrap analysis shows that 23 of the 50 sources in the Galactic plane footprint (46\%, for |b| ≤ 5) overlap a catalogued SNR, whereas random placement yields only 10.0±2.8 matches even if the underlying Galactic SNR population is ten times larger than currently catalogued; in the outer Galaxy, where chance alignment is rarest, 4 of 12 sources coincide with an SNR against a null expectation of ≲2. We estimate that at least a quarter, and up to half, of the 1LHAASO Galactic-plane sources genuinely reside in SNR environments, consistent with a population dominated by pulsar wind nebulae, SNR--PWN composites, and cosmic-ray-illuminated clouds. Individual results include a new SNR candidate inside the TeV shell HESS~J1912+101, a radio candidate for the SNR hypothesised to explain the GeV emission of 1LHAASO~J1945+2424, and the first proposed counterparts of 1LHAASO~JJ0056+6343u and 1LHAASO~J2200+5643u.
Related
- Catalogue of Solar Radio Bursts Detected by the LOFAR LV614 Station at the Irbene Observatory during Solar Cycle 25
- ApPolLO: Apertif counterparts of Polarised LOFAR sources
- Correlation of galactic very-high-energy gamma-ray sources detected by LHAASO with high-energy neutrinos
- ApPolLO: Apertif counterparts of Polarised LOFAR sources
- ECOGAL. I. Project design and the first catalogue
BibTeX
@misc{arias2026lofar,
title = {{LOFAR follow-up of sources in the First LHAASO Catalogue}},
author = {Maria Arias and Timothy Shimwell and Martin Hardcastle and Roland Timmerman},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07119},
eprint = {2609.07119},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07119},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - LOFAR follow-up of sources in the First LHAASO Catalogue
AU - Maria Arias
AU - Timothy Shimwell
AU - Martin Hardcastle
AU - Roland Timmerman
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07119
UR - https://arxiv.org/abs/2609.07119
AB - The First LHAASO Catalogue lists 90 sources of very-high-energy gamma-ray emission, many without an established counterpart at other frequencies, reopening the question of which Galactic accelerators produce the highest-energy cosmic rays. We search for low-frequency radio counterparts to the 55 1LHAASO sources that fall within the Galactic fields of the LOFAR Two-metre Sky Survey Data Release Three (LoTSS-DR3), using 144~MHz continuum maps at 6'' and 20'' resolution, complemented with archival data from other radio surveys where available. We present an overview of the radio emission towards all 55 sources, and identify the structures potentially associated with the gamma-ray emission. We report 24 new supernova remnant (SNR) candidates, nine flat-spectrum radio shells with faint or no infrared counterpart, and six sources with no clear Galactic radio emission present in the LOFAR maps. A bootstrap analysis shows that 23 of the 50 sources in the Galactic plane footprint (46\%, for |b| ≤ 5) overlap a catalogued SNR, whereas random placement yields only 10.0±2.8 matches even if the underlying Galactic SNR population is ten times larger than currently catalogued; in the outer Galaxy, where chance alignment is rarest, 4 of 12 sources coincide with an SNR against a null expectation of ≲2. We estimate that at least a quarter, and up to half, of the 1LHAASO Galactic-plane sources genuinely reside in SNR environments, consistent with a population dominated by pulsar wind nebulae, SNR--PWN composites, and cosmic-ray-illuminated clouds. Individual results include a new SNR candidate inside the TeV shell HESS~J1912+101, a radio candidate for the SNR hypothesised to explain the GeV emission of 1LHAASO~J1945+2424, and the first proposed counterparts of 1LHAASO~JJ0056+6343u and 1LHAASO~J2200+5643u.
ER -