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arXiv · 2301.10801

The SCUBA-2 Large eXtragalactic Survey: 850um map, catalogue and the bright-end number counts of the XMM-LSS field

T. K. Garratt·J. E. Geach·Y. Tamura·K. E. K. Coppin·M. Franco·Y. Ao·C. -C. Chen·C. Cheng·D. L. Clements·Y. S. Dai·H. Dannerbauer·T. R. Greve·B. Hatsukade·H. S. Hwang·L. Jiang·K. Kohno·M. P. Koprowski·M. J. Michalowski·M. Sawicki·D. Scott·H. Shim·T. T. Takeuchi·W. -H. Wang·Y. Q. Xue·C. Yang
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Abstract

We present 850um imaging of the XMM-LSS field observed for 170 hours as part of the James Clerk Maxwell Telescope SCUBA-2 Large eXtragalactic Survey (S2LXS). S2LXS XMM-LSS maps an area of 9 square degrees, reaching a moderate depth of 1-sigma ~ 4 mJy/beam. This is the largest contiguous area of extragalactic sky mapped by JCMT at 850um to date. The wide area of the S2LXS XMM-LSS survey allows us to probe the ultra-bright (S_850um > 15 mJy), yet rare submillimetre population. We present the S2LXS XMM-LSS catalogue, which comprises 40 sources detected at >5-sigma significance, with deboosted flux densities in the range of 7 mJy to 48 mJy. We robustly measure the bright-end of the 850um number counts at flux densities >7 mJy, reducing the Poisson errors compared to existing measurements. The S2LXS XMM-LSS observed number counts show the characteristic upturn at bright fluxes, expected to be motivated by local sources of submillimetre emission and high-redshift strongly lensed galaxies. We find that the observed 850um number counts are best reproduced by model predictions that include either strong lensing or source blending from a 15 arcsec beam, indicating that both may make an important contribution to the observed over-abundance of bright single dish 850um selected sources. We make the S2LXS XMM-LSS 850um map and >5-sigma catalogue presented here publicly available.

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T. K. Garratt, J. E. Geach, Y. Tamura, K. E. K. Coppin, M. Franco, Y. Ao, C. -C. Chen, C. Cheng, D. L. Clements, Y. S. Dai, H. Dannerbauer, T. R. Greve, B. Hatsukade, H. S. Hwang, L. Jiang, K. Kohno, M. P. Koprowski, M. J. Michalowski, M. Sawicki, D. Scott, H. Shim, T. T. Takeuchi, W. -H. Wang, Y. Q. Xue, C. Yang. 2023-01-25. The SCUBA-2 Large eXtragalactic Survey: 850um map, catalogue and the bright-end number counts of the XMM-LSS field. https://doi.org/10.1093/mnras/stad307

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