Galaxy And Mass Assembly: A Comparison between Galaxy-Galaxy Lens Searches in KiDS/GAMA

Abstract

Strong gravitational lenses are a rare and instructive type of astronomical object. Identification has long relied on serendipity, but different strategies -- such as mixed spectroscopy of multiple galaxies along the line of sight, machine learning algorithms, and citizen science -- have been employed to identify these objects as new imaging surveys become available. We report on the comparison between spectroscopic, machine learning, and citizen science identification of galaxy-galaxy lens candidates from independently constructed lens catalogs in the common survey area of the equatorial fields of the GAMA survey. In these, we have the opportunity to compare high-completeness spectroscopic identifications against high-fidelity imaging from the Kilo Degree Survey (KiDS) used for both machine learning and citizen science lens searches. We find that the three methods -- spectroscopy, machine learning, and citizen science -- identify 47, 47, and 13 candidates respectively in the 180 square degrees surveyed. These identifications barely overlap, with only two identified by both citizen science and machine learning. We have traced this discrepancy to inherent differences in the selection functions of each of the three methods, either within their parent samples (i.e. citizen science focuses on low-redshift) or inherent to the method (i.e. machine learning is limited by its training sample and prefers well-separated features, while spectroscopy requires sufficient flux from lensed features to lie within the fiber). These differences manifest as separate samples in estimated Einstein radius, lens stellar mass, and lens redshift. The combined sample implies a lens candidate sky-density $\sim 0.59$ deg${}^{-2}$ and can inform the construction of a training set spanning a wider mass-redshift space.

arXiv comment22 figures, 6 tables, accepted for publication in The Astronomical Journal

References in corpus (77)

• Stellar population synthesis at the resolution of 2003
• The Seventh Data Release of the Sloan Digital Sky Survey
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• A 3% Solution: Determination of the Hubble Constant with the Hubble Space Telescope and Wide Field Camera 3
• Galaxy Zoo : Morphologies derived from visual inspection of galaxies from the Sloan Digital Sky Survey
• Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release
• Spectroscopic Target Selection for the Sloan Digital Sky Survey: The Luminous Red Galaxy Sample
• The formation history of elliptical galaxies
• Galaxy And Mass Assembly: Stellar Mass Estimates
• Spectral Classification and Redshift Measurement for the SDSS-III Baryon Oscillation Spectroscopic Survey
• Galaxy And Mass Assembly (GAMA): end of survey report and data release 2
• The Sloan Lens ACS Survey. X. Stellar, Dynamical, and Total Mass Correlations of Massive Early-type Galaxies
• Emergent Gravity and the Dark Universe
• The Sloan Lens ACS Survey. III - The Structure and Formation of Early-type Galaxies and their Evolution since z~1
• The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies
• The Sloan Lens ACS Survey. IV: the mass density profile of early-type galaxies out to 100 effective radii
• The Sloan Lens ACS Survey. V. The Full ACS Strong-Lens Sample
• The Kilo-Degree Survey
• GAMA: towards a physical understanding of galaxy formation
• Gravitational detection of a low-mass dark satellite at cosmological distance
• Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function at z < 0.06
• H0LiCOW I. $H_0$ Lenses in COSMOGRAIL's Wellspring: Program Overview
• Galaxy And Mass Assembly (GAMA): Structural Investigation of Galaxies via Model Analysis (SIGMA)
• The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees
• The Sloan Lens ACS Survey. IX. Colors, Lensing and Stellar Masses of Early-type Galaxies
• The first and second data releases of the Kilo-Degree Survey
• Galaxy And Mass Assembly (GAMA): the G02 field, Herschel-ATLAS target selection and Data Release 3
• The Sloan-Lens ACS Survey II: stellar populations and internal structure of early-type lens galaxies
• A SHARP view of H0LiCOW: $H_0$ from three time-delay gravitational lens systems with adaptive optics imaging
• Two-dimensional kinematics of SLACS lenses: III. Mass structure and dynamics of early-type lens galaxies beyond z ~ 0.1
• Galaxy And Mass Assembly (GAMA): Mid-Infrared Properties and Empirical Relations from $WISE$
• The third data release of the Kilo-Degree Survey and associated data products
• The Sloan Lens ACS Survey. VII. Elliptical Galaxy Scaling Laws from Direct Observational Mass Measurements
• The Sloan Lens ACS Survey. VI: Discovery and analysis of a double Einstein ring
• The BOSS Emission-Line Lens Survey (BELLS). I. A large spectroscopically selected sample of Lens Galaxies at redshift ~ 0.5
• Finding Strong Gravitational Lenses in the Kilo Degree Survey with Convolutional Neural Networks
• Galaxy And Mass Assembly (GAMA): Accurate Panchromatic Photometry from Optical Priors using LAMBDAR
• A precise extragalactic test of General Relativity
• The SL2S Galaxy-scale Lens Sample. V. Dark Matter Halos and Stellar IMF of Massive Early-type Galaxies out to Redshift 0.8
• Galaxy And Mass Assembly (GAMA): autoz spectral redshift measurements, confidence and errors
• Galaxy and Mass Assembly (GAMA): Optimal Tiling of Dense Surveys with a Multi-Object Spectrograph
• The Dawes Review 8: Measuring the Stellar Initial Mass Function
• RingFinder: automated detection of galaxy-scale gravitational lenses in ground-based multi-filter imaging data
• The Sloan Lens ACS Survey. VIII. The relation between environment and internal structure of early-type galaxies
• Space Warps: I. Crowd-sourcing the Discovery of Gravitational Lenses
• LinKS: Discovering galaxy-scale strong lenses in the Kilo-Degree Survey using Convolutional Neural Networks
• The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-Scale Strong Lenses
• The Sloan Lens ACS Survey. XII. Extending Strong Lensing to Lower Masses
• Finding Strong Gravitational Lenses in the DESI DECam Legacy Survey
• Strong lensing optical depths in a LCDM universe II: the influence of the stellar mass in galaxies
• Sloan Digital Sky Survey Spectroscopic Lens Search. I. Discovery of Intermediate-Redshift Star-Forming Galaxies Behind Foreground Luminous Red Galaxies
• The Evolution of Dust Opacity in Galaxies
• The Scaling of Stellar Mass and Central Stellar Velocity Dispersion for Quiescent galaxies at z < 0.7
• Version 1 of the Hubble Source Catalog
• New high-quality strong lens candidates with deep learning in the Kilo Degree Survey
• The BOSS Emission-Line Lens Survey. III. : Strong Lensing of Ly$\alpha$ Emitters by Individual Galaxies
• GAMA/G10-COSMOS/3D-HST: Evolution of the galaxy stellar mass function over 12.5Gyrs
• Integrating human and machine intelligence in galaxy morphology classification tasks
• Resolving Quiescent Galaxies at $z\gtrsim 2$: I. Search for Gravitationally Lensed Sources and Characterization of their Structure, Stellar Populations, and Line Emission
• SHELS: A Complete Galaxy Redshift Survey with R$\le$20.6
• Molecular gas properties of a lensed star-forming galaxy at z~3.6: a case study
• Testing Convolutional Neural Networks for finding strong gravitational lenses in KiDS
• Infrared Properties of Close Pairs of Galaxies
• Beyond subhalos: Probing the collective effect of the Universe's small-scale structure with gravitational lensing
• SHELS: Complete Redshift Surveys of Two Widely Separated Fields
• Galaxy And Mass Assembly (GAMA): The Consistency of GAMA and WISE Derived Mass-to-Light Ratios
• A new strong-lensing galaxy at z=0.066: Another elliptical galaxy with a lightweight IMF
• Galaxy-Galaxy Lensing in HSC: Validation Tests and the Impact of Heterogeneous Spectroscopic Training Sets
• Quantifying the Biases of Spectroscopically Selected Gravitational Lenses
• Testing Verlinde's emergent gravity in early-type galaxies
• The frequency of dust lanes in edge-on spiral galaxies identified by Galaxy Zoo in KiDS imaging of GAMA targets
• Galaxy And Mass Assembly (GAMA) Blended Spectra Catalog: Strong Galaxy-Galaxy Lens and Occulting Galaxy Pair Candidates
• Two-dimensional kinematics of SLACS lenses - IV. The complete VLT-VIMOS data set
• Improved mass constraints for two nearby strong-lensing elliptical galaxies from Hubble Space Telescope Imaging
• Galaxy-scale gravitational lens candidates from the Hyper Suprime-Cam imaging survey and the Galaxy And Mass Assembly spectroscopic survey
• Strong Lensing Analysis of the Powerful Lensing Cluster MACS J2135.2-0102 ($z$=0.33)
• Strong Lensing Analysis of the Galaxy Cluster MACS J1319.9+7003 and the Discovery of a Shell Galaxy