Euclid: The Early Release Observations Lens Search Experiment

Collaboration
Aug 12, 2024
21 pages
e-Print:
Experiments:

Citations per year

202320242025043
Abstract: (arXiv)
We investigate the ability of the Euclid telescope to detect galaxy-scale gravitational lenses. To do so, we perform a systematic visual inspection of the 0.7deg20.7\,\rm{deg}^2 Euclid ERO data towards the Perseus cluster using both the high-resolution VIS IEI_{\scriptscriptstyle\rm E} band, and the lower resolution NISP bands. We inspect every extended source brighter than magnitude 2323 in IEI_{\scriptscriptstyle\rm E} with 4141 expert human classifiers. This amounts to 1208612\,086 stamps of 10×1010^{\prime\prime}\,\times\,10^{\prime\prime}. We find 33 grade A and 1313 grade B candidates. We assess the validity of these 1616 candidates by modelling them and checking that they are consistent with a single source lensed by a plausible mass distribution. Five of the candidates pass this check, five others are rejected by the modelling and six are inconclusive. Extrapolating from the five successfully modelled candidates, we infer that the full 14000deg214\,000\,{\rm deg}^2 of the Euclid Wide Survey should contain 10000030000+70000100\,000^{+70\,000}_{-30\,000} galaxy-galaxy lenses that are both discoverable through visual inspection and have valid lens models. This is consistent with theoretical forecasts of 170000170\,000 discoverable galaxy-galaxy lenses in Euclid. Our five modelled lenses have Einstein radii in the range 0. ⁣ ⁣68<θE<1. ⁣ ⁣240.\!\!^{\prime\prime}68\,<\,\theta_\mathrm{E}\,<1.\!\!^{\prime\prime}24, but their Einstein radius distribution is on the higher side when compared to theoretical forecasts. This suggests that our methodology is likely missing small Einstein radius systems. Whilst it is implausible to visually inspect the full Euclid data set, our results corroborate the promise that Euclid will ultimately deliver a sample of around 10510^5 galaxy-scale lenses.
Note:
  • 21 pages, 20 figures, submitted to A&A