Quasar Lenses and Galactic Streams: Outlier Selection and GAIA Multiplet Detection

Abstract

I describe two novel techniques originally devised to select strongly lensed quasar candidates in wide-field surveys. The first relies on outlier selection in optical and mid-infrared magnitude space; the second combines mid-infrared colour selection with GAIA spatial resolution, to identify multiplets of objects with quasar-like colours. Both methods have already been applied successfully to the SDSS, ATLAS and DES footprints: besides recovering known lenses from previous searches, they have led to new discoveries, including quadruply lensed quasars, which are rare within the rare-object class of quasar lenses. As a serendipitous by-product, at least four candidate Galactic streams in the South have been identified among foreground contaminants. There is considerable scope for tailoring the WISE-GAIA multiplet search to stellar-like objects, instead of quasar-like, and to automatically detect Galactic streams.

MNRAS subm. 21/04, revised version after referee report. 10 pages, 5 figures

References in corpus (17)

• The Gaia mission
• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog
• The Sloan Digital Sky Survey Quasar Lens Search. I. Candidate Selection Algorithm
• The weirdest SDSS galaxies: results from an outlier detection algorithm
• A Synoptic Map of Halo Substructures from the Pan-STARRS1 3π Survey
• ATLAS lifts the Cup: Discovery of a New Milky Way satellite in Crater
• A calibration of the stellar mass fundamental plane at z ~ 0.5 using the micro-lensing induced flux ratio anomalies of macro-lensed quasars
• VDES J2325-5229 a z=2.7 gravitationally lensed quasar discovered using morphology independent supervised machine learning
• Data Mining for Gravitationally Lensed Quasars
• Gaia data release 1, the photometric data
• CHITAH: Strong-gravitational-lens hunter in imaging surveys
• H0LiCOW VI. Testing the fidelity of lensed quasar host galaxy reconstruction
• A Study of Quasar Selection in the Dark Energy Survey Supernova fields
• Population mixtures and searches of lensed and extended quasars across photometric surveys

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• Fourteen candidate RR Lyrae star streams in the inner Galaxy
• Data mining techniques on astronomical spectra data. II : Classification Analysis
• A Survey for High-redshift Gravitationally Lensed Quasars and Close Quasars Pairs. I. the Discoveries of an Intermediately-lensed Quasar and a Kpc-scale Quasar Pair at $z\sim 5$