A new strong-lensing galaxy at a redshift of 0.066

Low redshift strong gravitational lenses are sought after for their uniquely precise stellar mass measurement. This well constrained value can be used to infer the stellar population at the time of formation, through the mass-to-light ratio.

William Collier, a CEA PhD student, along with supervisors Russell Smith and John Lucey, recently reported the discovery of a strong-lensing elliptical galaxy at a redshift of 0.066. This lensing system, shown below, was discovered during a systematic search for strong lenses within archival MUSE data. It has extremely bright lensed arcs (marked A and B, in panel b), which are visible prior to removal of the foregound (lens) galaxy light. With the foreground light removed, in panel c, two bright and extended arcs can be seen. This is only the fourth strong lensing, z<0.1, confirmed massive elliptical galaxy strong lens. All four have been inferred to have formed with a stellar population alike to those observed forming in the Milky-Way.
Images of the newly-discovered, low-redshift, gravitational lens system

Link to the original research paper: arxiv.org/abs/1803.07082

Contacts from CEA, Durham:

William Collier

Russell Smith

John Lucey