The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant Luminous Red Galaxy

Abstract

We report the discovery of an almost complete Einstein ring of diameter 10" in Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5). Spectroscopic data from the 6m telescope of the Special Astrophysical Observatory reveals that the deflecting galaxy has a line-of-sight velocity dispersion in excess of 400 km/s and a redshift of 0.444, whilst the source is a star-forming galaxy with a redshift of 2.379. From its color and luminosity, we conclude that the lens is an exceptionally massive Luminous Red Galaxy (LRG) with a mass within the Einstein radius of 5 x 10^12 solar masses. This remarkable system provides a laboratory for probing the dark matter distribution in LRGs at distances out to 3 effective radii, and studying the properties of high redshift star-forming galaxies.

ApJ (Letters), in press

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Cited by in corpus (30)

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• Two New Large Separation Gravitational Lenses from SDSS
• Gravitational lenses and lens candidates identified from the COSMOS field
• Unexpected Circular Radio Objects at High Galactic Latitude
• Discovery of A Very Bright, Strongly-Lensed z=2 Galaxy in the SDSS DR5
• The Sloan Bright Arcs Survey : Six Strongly Lensed Galaxies at z=0.4-1.4
• HOLISMOKES -- IV. Efficient mass modeling of strong lenses through deep learning
• Kinematics of the Circumgalactic Medium of a $z=0.77$ Galaxy from MgII Tomography
• COOL-LAMPS I. An Extraordinarily Bright Lensed Galaxy at Redshift 5.04
• Dark Matter in Cosmology
• Streamlined Lensed Quasar Identification in Multiband Images via Ensemble Networks
• The evolution of late-type galaxies from CASSOWARY lensing systems
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• Zooming into the Cosmic Horseshoe: new insights on the lens profile and the source shape
• Strong Lensing by Binary Galaxies Modelled as Isothermal Spheres
• X-shooter Observations of the Gravitational Lens System CASSOWARY 5
• Spectroscopy of CASSOWARY gravitationally-lensed galaxies in SDSS: characterisation of an extremely bright reionization-era analog at $z=1.42$
• The SDSS Discovery of a Strongly Lensed Post-Starburst Galaxy at z=0.766
• Discovery of four gravitational lensing systems by clusters in the SDSS DR6
• Pixelated Reconstruction of Foreground Density and Background Surface Brightness in Gravitational Lensing Systems using Recurrent Inference Machines
• Efficient Mass Estimate at the Core of Strong Lensing Galaxy Clusters Using the Einstein Radius
• Unveiling a 36 Billion Solar Mass Black Hole at the Centre of the Cosmic Horseshoe Gravitational Lens
• Relativistic effects cannot explain galactic dynamics
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• Accelerating lensed quasar discovery and modeling with physics-informed variational autoencoders
• The AGEL Survey: Spectroscopic Confirmation of Strong Gravitational Lenses in the DES and DECaLS Fields Selected Using Convolutional Neural Networks
• Lensed stars in galaxy-galaxy strong lensing -- a JWST prediction for the Cosmic Horseshoe