Deep Extragalactic VIsible Legacy Survey (DEVILS): DR1 Blended Spectra Search for Candidate Strong Gravitational Lenses

TL;DR

This paper presents a catalog of blended spectra from the DEVILS survey, identifying nine strong gravitational lens candidates, including the highest redshift lenses found via spectroscopic blends, with potential for future detailed studies.

Contribution

It introduces a new catalog of blended spectra from DEVILS and identifies the first high-redshift strong lens candidates through spectroscopic blending analysis.

Findings

Nine strong lensing candidates identified in the COSMOS field.

High-redshift lenses found, surpassing previous spectroscopic surveys.

Success rate of candidate identification is approximately 0.1%.

Abstract

Here, we present a catalog of blended spectra in Data Release 1 of the Deep Extragalactic VIsible Legacy Survey (DEVILS) on the Anglo-Australian Telescope (AAT). Of the 23197 spectra, 181 showed signs of a blend of redshifts and spectral templates. We examine these blends in detail for signs of either a candidate strong lensing galaxy or a useful overlapping galaxy pair. One of the three DEVILS target fields, COSMOS (D10) is close to complete and it is fully imaged with Hubble Space Telescope Advanced Camera for Surveys (HST/ACS) and we visually examine the 57 blended spectra in this field in the F814W postage stamps. Nine are classical strong lensing candidates with an elliptical as the lens, out to higher redshifts than any previous search with spectroscopic surveys such as SDSS or GAMA. The gravitational lens candidate success rate similar to earlier such searches (0.1%). Strong gravitational lenses identified with blended spectroscopy have typically shown a high success rate (>70%) which make these interesting targets for future higher resolution lensing studies, monitoring for supernovae cosmography, or searches for magnified atomic hydrogen signal.