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The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release

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The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release. / Hardcastle, M. J.; Horton, M. A.; Williams, W. L. et al.
Arxiv, 2023.

Research output: Working paper › Preprint

Harvard

Hardcastle, MJ, Horton, MA, Williams, WL, Duncan, KJ, Alegre, L, Barkus, B, Croston, JH, Dickinson, H, Osinga, E, Röttgering, HJA, Sabater, J, Shimwell, TW, Best, PN, Botteon, A, Brüggen, M, Drabent, A, Gasperin, FD, Gürkan, G, Hajduk, M, Hale, CL, Hoeft, M, Jamrozy, M, Kunert-Bajraszewska, M, Kondapally, R, Magliocchetti, M, Mahatma, VH, Mostert, RIJ, Pajdosz-Śmierciak, U, Petley, J, Pierce, JCS, Prandoni, I, Schwarz, DJ, Shulewski, A, Siewert, TM, Stott, JP, Tang, H, Vaccari, M, Desbled, S, Goyal, A, Gonano, V, Hanset, M, Kurtz, W, Mielle, L, Molloy, CS, Roth, R, Terentev, IA & Torres, M 2023 'The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release' Arxiv.

APA

Hardcastle, M. J., Horton, M. A., Williams, W. L., Duncan, K. J., Alegre, L., Barkus, B., Croston, J. H., Dickinson, H., Osinga, E., Röttgering, H. J. A., Sabater, J., Shimwell, T. W., Best, P. N., Botteon, A., Brüggen, M., Drabent, A., Gasperin, F. D., Gürkan, G., Hajduk, M., ... Torres, M. (in press). The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release. Arxiv.

Vancouver

Hardcastle MJ, Horton MA, Williams WL, Duncan KJ, Alegre L, Barkus B et al. The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release. Arxiv. 2023 Aug 30.

Author

Hardcastle, M. J. ; Horton, M. A. ; Williams, W. L. et al. / The LOFAR Two-Metre Sky Survey (LoTSS) : VI. Optical identifications for the second data release. Arxiv, 2023.

Bibtex

@techreport{fee065685f064ae2ac948d2cd50ff07e,
title = "The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release",
abstract = "The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% of the northern sky, with a total area of $\sim 5,700$ deg$^2$. The high angular resolution of LOFAR with Dutch baselines (6 arcsec) allows us to carry out optical identifications of a large fraction of the detected radio sources without further radio followup; however, the process is made more challenging by the many extended radio sources found in LOFAR images as a result of its excellent sensitivity to extended structure. In this paper we present source associations and identifications for sources in the second data release based on optical and near-infrared data, using a combination of a likelihood-ratio cross-match method developed for our first data release, our citizen science project Radio Galaxy Zoo: LOFAR, and new approaches to algorithmic optical identification, together with extensive visual inspection by astronomers. We also present spectroscopic or photometric redshifts for a large fraction of the optical identifications. In total 4,116,934 radio sources lie in the area with good optical data, of which 85% have an optical or infrared identification and 58% have a good redshift estimate. We demonstrate the quality of the dataset by comparing it with earlier optically identified radio surveys. This is by far the largest ever optically identified radio catalogue, and will permit robust statistical studies of star-forming and radio-loud active galaxies. ",
keywords = "astro-ph.GA",
author = "Hardcastle, {M. J.} and Horton, {M. A.} and Williams, {W. L.} and Duncan, {K. J.} and L. Alegre and B. Barkus and Croston, {J. H.} and H. Dickinson and E. Osinga and R{\"o}ttgering, {H. J. A.} and J. Sabater and Shimwell, {T. W.} and Best, {P. N.} and A. Botteon and M. Br{\"u}ggen and A. Drabent and Gasperin, {F. de} and G. G{\"u}rkan and M. Hajduk and Hale, {C. L.} and M. Hoeft and M. Jamrozy and M. Kunert-Bajraszewska and R. Kondapally and M. Magliocchetti and Mahatma, {V. H.} and Mostert, {R. I. J.} and U. Pajdosz-{\'S}mierciak and J. Petley and Pierce, {J. C. S.} and I. Prandoni and Schwarz, {D. J.} and A. Shulewski and Siewert, {T. M.} and Stott, {J. P.} and H. Tang and M. Vaccari and S. Desbled and A. Goyal and V. Gonano and M. Hanset and W. Kurtz and L. Mielle and Molloy, {C. S.} and R. Roth and Terentev, {I. A.} and M. Torres",
note = "29 pages. Accepted by A&A; data products available at https://lofar-surveys.org/dr2_release.html",
year = "2023",
month = aug,
day = "30",
language = "English",
publisher = "Arxiv",
type = "WorkingPaper",
institution = "Arxiv",

}

RIS

TY - UNPB

T1 - The LOFAR Two-Metre Sky Survey (LoTSS)

T2 - VI. Optical identifications for the second data release

AU - Hardcastle, M. J.

AU - Horton, M. A.

AU - Williams, W. L.

AU - Duncan, K. J.

AU - Alegre, L.

AU - Barkus, B.

AU - Croston, J. H.

AU - Dickinson, H.

AU - Osinga, E.

AU - Röttgering, H. J. A.

AU - Sabater, J.

AU - Shimwell, T. W.

AU - Best, P. N.

AU - Botteon, A.

AU - Brüggen, M.

AU - Drabent, A.

AU - Gasperin, F. de

AU - Gürkan, G.

AU - Hajduk, M.

AU - Hale, C. L.

AU - Hoeft, M.

AU - Jamrozy, M.

AU - Kunert-Bajraszewska, M.

AU - Kondapally, R.

AU - Magliocchetti, M.

AU - Mahatma, V. H.

AU - Mostert, R. I. J.

AU - Pajdosz-Śmierciak, U.

AU - Petley, J.

AU - Pierce, J. C. S.

AU - Prandoni, I.

AU - Schwarz, D. J.

AU - Shulewski, A.

AU - Siewert, T. M.

AU - Stott, J. P.

AU - Tang, H.

AU - Vaccari, M.

AU - Desbled, S.

AU - Goyal, A.

AU - Gonano, V.

AU - Hanset, M.

AU - Kurtz, W.

AU - Mielle, L.

AU - Molloy, C. S.

AU - Roth, R.

AU - Terentev, I. A.

AU - Torres, M.

N1 - 29 pages. Accepted by A&A; data products available at https://lofar-surveys.org/dr2_release.html

PY - 2023/8/30

Y1 - 2023/8/30

N2 - The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% of the northern sky, with a total area of $\sim 5,700$ deg$^2$. The high angular resolution of LOFAR with Dutch baselines (6 arcsec) allows us to carry out optical identifications of a large fraction of the detected radio sources without further radio followup; however, the process is made more challenging by the many extended radio sources found in LOFAR images as a result of its excellent sensitivity to extended structure. In this paper we present source associations and identifications for sources in the second data release based on optical and near-infrared data, using a combination of a likelihood-ratio cross-match method developed for our first data release, our citizen science project Radio Galaxy Zoo: LOFAR, and new approaches to algorithmic optical identification, together with extensive visual inspection by astronomers. We also present spectroscopic or photometric redshifts for a large fraction of the optical identifications. In total 4,116,934 radio sources lie in the area with good optical data, of which 85% have an optical or infrared identification and 58% have a good redshift estimate. We demonstrate the quality of the dataset by comparing it with earlier optically identified radio surveys. This is by far the largest ever optically identified radio catalogue, and will permit robust statistical studies of star-forming and radio-loud active galaxies.

AB - The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% of the northern sky, with a total area of $\sim 5,700$ deg$^2$. The high angular resolution of LOFAR with Dutch baselines (6 arcsec) allows us to carry out optical identifications of a large fraction of the detected radio sources without further radio followup; however, the process is made more challenging by the many extended radio sources found in LOFAR images as a result of its excellent sensitivity to extended structure. In this paper we present source associations and identifications for sources in the second data release based on optical and near-infrared data, using a combination of a likelihood-ratio cross-match method developed for our first data release, our citizen science project Radio Galaxy Zoo: LOFAR, and new approaches to algorithmic optical identification, together with extensive visual inspection by astronomers. We also present spectroscopic or photometric redshifts for a large fraction of the optical identifications. In total 4,116,934 radio sources lie in the area with good optical data, of which 85% have an optical or infrared identification and 58% have a good redshift estimate. We demonstrate the quality of the dataset by comparing it with earlier optically identified radio surveys. This is by far the largest ever optically identified radio catalogue, and will permit robust statistical studies of star-forming and radio-loud active galaxies.

KW - astro-ph.GA

M3 - Preprint

BT - The LOFAR Two-Metre Sky Survey (LoTSS)

PB - Arxiv

ER -