Data · dataset · 2022
The LOFAR Two-metre Sky Survey (LoTSS) V. Second data release (P348+33)
Listed in SURF Data Repository
In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS) we present 120-168 MHz images covering 27% of the northern sky.
Description
Our coverage is split into two regions centred at approximately 12h45m +44◦30′ and 1h00m +28◦ 00′ and spanning 4178 and 1457 square degrees respectively. The images were derived from 3,451 hrs (7.6 PB) of LOFAR High Band Antenna data which were corrected for the direction-independent instrumental properties as well as direction-dependent ionospheric distortions during extensive, but fully automated, data processing.
A catalogue of 4,396,228 radio sources is derived from our total intensity (Stokes I) maps, where the majority of these have never been detected at radio wavelengths before. At 6′′ resolution, our full bandwidth Stokes I continuum maps with a central frequency of 144 MHz have: a median rms sensitivity of 83 μ Jy/beam; a flux density scale accuracy of approximately 10%; an astrometric accuracy of 0.2′′; and we estimate the point-source completeness to be 90% at a peak brightness of 0.8 mJy/beam.
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By creating three 16 MHz bandwidth images across the band we are able to measure the in-band spectral index of many sources, albeit with an error on the derived spectral index of > ±0.2 which is a consequence of our flux-density scale accuracy and small fractional bandwidth. Our circular polarisation (Stokes V) 20′′ resolution 120-168 MHz continuum images have a median rms sensitivity of 95 μ Jy/beam, and we estimate a Stokes I to Stokes V leakage of 0.056%.
Our linear polarisation (Stokes Q and Stokes U) image cubes consist of 480 97.6 kHz wide planes and have a median rms sensitivity per plane of 10.8mJy/beam at 4′ and 2.2mJy/beam at 20′′; we estimate the Stokes I to Stokes Q/U leakage to be approximately 0.2%. Here we characterise and publicly release our Stokes I, Q, U and V images in addition to the calibrated uv-data to facilitate the thorough scientific exploitation of this unique dataset.
This is field P348+33.
Links
Where it is published
- SURF Data Repository record repository.surf.nl/records/abbat-ja342 ↗
landing page · from repository surf nl
Catalogue records · 1
- InvenioRDM API repository.surf.nl/api/records/abbat-ja342 ↗
metadata API · from repository surf nl
Topics
- Stated by source
- catalogues · radio continuum: general · surveys · techniques: image processing
- From keywords
- Engineering · Humanities · Life Sciences · Social Science
- Inferred from text
- Geomatic engineering 69% · Image 75%
Provenance · 1 source records, 15 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| SURF Data Repository | abbat-ja342 | 7 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[field].anzsrc:group:4013 | enrichment · repository surf nl | taxonomy-embedding@1.0.0 | title+keywords+description (69%) |
| concepts[field].local:field:engineering | mapping · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[field].local:field:humanities | mapping · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[field].local:field:life-sciences | mapping · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[field].local:field:social-science | mapping · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[modality].local:modality:image | enrichment · repository surf nl | keyword-concept-rules@1.0.0 | title+description (75%) |
| concepts[topic].invenio_subject:repository_surf_nl:catalogues | source · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[topic].invenio_subject:repository_surf_nl:radio-continuum-general | source · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[topic].invenio_subject:repository_surf_nl:surveys | source · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| concepts[topic].invenio_subject:repository_surf_nl:techniques-image-processing | source · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| description | source · repository surf nl | connector:repository_surf_nl@1.0.0 | /metadata/description |
| publication_date | source · repository surf nl | connector:repository_surf_nl@1.0.0 | |
| title | source · repository surf nl | connector:repository_surf_nl@1.0.0 | /metadata/title |
| updated_date | source · repository surf nl | connector:repository_surf_nl@1.0.0 |