Strong Lensing

Large gravitational masses can lens objects at higher redshifts. Luminous red galaxies (LRG) are some of the largest know galaxies in the universe, and have been observed to lens emission line galaxies (ELG) at higher redshifts. The two spectra below are good examples of an LRG lensing a ELG from the Sloan Digital Sky Survey (SDSS). The (ELG) are recognized by their [OII] 3727 and 3729 A, [OIII] 4960 and 5008 A, H alpha 6564 A, H beta 4862 A, H gamma 4341 A, H delta 4102 A, [NII] 6549 and 6585 A, and [SII] 6718 and 6732 A emission lines.

I have used the Sky Residual Correction technique detailed here, https://sites.bu.edu/murdock-hart/sky-subtraction/sky-residual-correction/, to assist in the search for gravitationally lensed ELG in the SDSS and Baryon-Acoustic Oscillation Spectroscopic Survey (BOSS) data sets.