A strong-lensing elliptical galaxy in the MaNGA survey

Abstract

I report discovery of a new galaxy-scale gravitational lens system, identified using public data from the MaNGA survey, as part of a systematic search for lensed background line-emitters. The lens is SDSS J170124.01+372258.0, a giant elliptical galaxy with velocity dispersion $\sigma =256$ km/s, at a redshift of $z_l=0.122$. After modelling and subtracting the target galaxy light, the integral-field data-cube reveals [OII], [OIII] and H$\beta$ emission lines corresponding to a source at $z_s=0.791$, forming an identifiable ring around the galaxy center. The Einstein radius is $R_{Ein}\approx 2.3$ arcsec, projecting to ~5 kpc at the distance of the lens. The total projected lensing mass is $(3.6\pm 0.6)\times 10^{11}{M}_{\odot }$, and the total J-band mass-to-light ratio is $3.0\pm 0.7$ solar units. Plausible estimates of the likely dark matter content could reconcile this with a Milky-Way-like initial mass function (for which M/L~1.5 is expected), but heavier IMFs are by no means excluded with the present data. An alternative interpretation of the system, with a more complex source plane, is also discussed. The discovery of this system bodes well for future lens searches based on MaNGA and other integral-field spectroscopic surveys.

MNRAS accepted 5th August 2016

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Cited by in corpus (3)

• Subaru FOCAS IFU observations of two z=0.12 strong-lensing elliptical galaxies from SDSS MaNGA
• Deep Extragalactic VIsible Legacy Survey (DEVILS): DR1 Blended Spectra Search for Candidate Strong Gravitational Lenses
• SDSS-IV MaNGA: A Catalogue of Spectroscopically Detected Strong Galaxy-Galaxy Lens Candidates