Fakultät für Physik und Astronomie
STEPHEN PHILLIPS hostreviews.co.uk / UNSPLASH

EasyCritics: Arc-free detection of strong cluster lenses

Sebastian Stapelberg , ZAH/ITA

Strong gravitational lensing by galaxy clusters offers important insights into cosmology, dark matter and the high-redshift Universe. The blind search for giant arcs and multiple images in optical surveys has so far posed a considerable challenge due to the poor visibility of arcs and the presence of many false friends. This usually requires large visual inspection efforts to validate the results, which introduces a considerable bottleneck. In this talk I introduce the EasyCritics detection method, which identifies group- and cluster-scale lenses based on the optical properties of these lenses themselves instead of searching for arcs. Based on the well-tested assumption that optical light traces mass on cluster scales, EasyCritics models the mass and its lensing effect over the entire line of sight and throughout the search area to find the most likely strongly-lensing structures for a given, typical source redshift. In a first test application to the well-studied wide-field survey CFHTLenS, we find that EasyCritics recovers 70-80 % of the known lenses and identifies several new lens candidates missed due to poorly resolved arcs - while reducing the time spent on manual inspection by several orders of magnitude. Thus EasyCritics promises an important gain in efficiency and completeness for future lens searches.

ITA "blackboard" Colloquium
22 Oct 2018, 11:15
Philosophenweg, 12, 106

Add to calendar Add to calendar
Today:
There are no scheduled talks today.
Upcoming:
How clumpy was the intergalactic medium during reionization?
Frederick Davies
Thu, 4 Apr 2024, 11:00
TBD
TBD
Thu, 4 Apr 2024, 11:00
Recent research results from the HKU Late State stellar evolution team - Strange Galactic alignments and solving the sulphur anomaly in Planetary Nebulae
Quentin Parker
Fri, 5 Apr 2024, 11:00
TBD
TBD
Thu, 11 Apr 2024, 11:00
Explaining the simplicity of the cosmos
Prof. Neil Turok
Thu, 11 Apr 2024, 18:30