A New Einstein Cross Gravitational Lens of a Lyman-break Galaxy
Abstract
We report the study of an “Einstein Cross” configuration first identified in a set of HST images by Cerny et al. Deep spectroscopic observations obtained at the Spanish 10.4 m Gran Telescopio Canarias telescope, allowed us to demonstrate the lens nature of the system, that consists of a Lyman-break galaxy (LBG), not a quasi-stellar object as is usually the case, at z = 3.03 lensed by a galaxy at z = 0.556. Combining the new spectroscopy with the archival HST data, it turns out that the lens is an elliptical galaxy with M V = -21.0, effective radius 2.8 kpc, and stellar velocity dispersion σ = 208 ± 39 km s-1. The source is an LBG with Lyα luminosity ∼L* at that redshift. From the modeling of the system, performed by assuming a singular isothermal ellipsoid (SIE) with external shear, we estimate that the flux source is magnified about 4.5 times, and the velocity dispersion of the lens is {σ }SIE}={197.9}-1.3+2.6 km s-1, in good agreement with the value derived spectroscopically. This is the second case known of an Einstein cross of an LBG.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2019
- DOI:
- 10.3847/2041-8213/ab0aeb
- arXiv:
- arXiv:1902.10964
- Bibcode:
- 2019ApJ...873L..14B
- Keywords:
-
- galaxies: elliptical and lenticular;
- cD;
- galaxies: high-redshift;
- gravitational lensing: strong;
- techniques: spectroscopic;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 7 pages, 6 figures, 1 Table