Identification and Characterization of Gravitationally-lensed Distant Star-forming Galaxies

Abstract

We use the far-infrared observations at 250, 350, 500 μm from the Herschel Space Observatory to identify strongly gravitationallylensed distant star-forming galaxies serendipitously located behind eight massive galaxy clusters. The appearance of multiple images of the same background object can help constrain the lens model, as well as to identify sources with exceptionally high magnifications that can serve as laboratories to study high-resolution details of distant galaxies otherwise beyond the capability of today’s observing facilities. We constrained the spectral energy distribution (SED) of the candidates and inferred their physical properties, including cosmological redshift (z, i.e., distance from the Earth), infrared luminosity (LIR) and the star formation rate (SFR). In order to accurately identify strongly-lensed images across multiple wavelengths for future studies, we matched the sources in the observations from the three additional wavebands that are available through our collaborators, including the radio images at 4 – 8 GHz from the Jansky Very Large Array, infrared images at 3.6 and 4.5 μm from the Spitzer Space Observatory, as well as optical images at 606 – 814 nm from the Hubble Space Telescope and at 623 nm (r 0 filter) from the Sloan Digital Sky Survey Data Release 12. These comparisons of images from multiple wavebands give us the identification of their precise coordinates and the characterization of their gravitationally-lensed features.