# Discovery of the Lensed Quasar System DES J0408-5354

## TL;DR

This paper reports the discovery and spectroscopic confirmation of a rare quadruply lensed quasar system in the Dark Energy Survey, demonstrating DES's potential to find more such systems and expand the known sample.

## Contribution

First discovery of a quad lensed quasar in DES, showcasing an effective search method and confirming the system with spectroscopic data.

## Key findings

- Confirmed the system as a quadruply lensed quasar at z=2.375
- Identified the lensing galaxy at z=0.597
- Demonstrated DES's capability to discover rare lensing systems

## Abstract

We report the discovery and spectroscopic confirmation of the quad-like lensed quasar system DES J0408-5354 found in the Dark Energy Survey (DES) Year 1 (Y1) data. This system was discovered during a search for DES Y1 strong lensing systems using a method that identified candidates as red galaxies with multiple blue neighbors. DES J0408-5354 consists of a central red galaxy surrounded by three bright (i < 20) blue objects and a fourth red object. Subsequent spectroscopic observations using the Gemini South telescope confirmed that the three blue objects are indeed the lensed images of a quasar with redshift z = 2.375, and that the central red object is an early-type lensing galaxy with redshift z = 0.597. DES J0408-5354 is the first quad lensed quasar system to be found in DES and begins to demonstrate the potential of DES to discover and dramatically increase the sample size of these very rare objects.