Galaxy And Mass Assembly (GAMA) blended spectra catalogue : strong galaxy–galaxy lens and occulting galaxy pair candidates.

Authors

Benne W. Holwerda, University of Louisville
I. K. Baldry, Liverpool John Moores University
M. Alpaslan, NASA Ames Research Center
A. E. Bauer, Australian Astronomical Observatory
J. Bland-Hawthorn, University of Sydney
S. Brough, Australian Astronomical Observatory
M. J. I. Brown, Monash University
M. E. Cluver, The University of Western Cape
C. J. Conselice, University of Nottingham
S. P. Driver, University of Western Australia
A. M. Hopkins, Australian Astronomical Observatory
D. H. Jones, Macquarie University
Angel R. Lopez-Sanchez, Australian Astronomical Observatory
J. Loveday, University of Sussex
M. J. Meyer, University of Western Australia
A. Moffett, University of Western Australia

Document Type

Article

Publication Date

6-2015

Department

Physics and Astronomy

Abstract

We present the catalogue of blended galaxy spectra from the Galaxy And Mass Assembly (GAMA) survey. These are cases where light from two galaxies are significantly detected in a single GAMA fibre. Galaxy pairs identified from their blended spectrum fall into two principal classes: they are either strong lenses, a passive galaxy lensing an emission-line galaxy; or occulting galaxies, serendipitous overlaps of two galaxies, of any type. Blended spectra can thus be used to reliably identify strong lenses for follow-up observations (high-resolution imaging) and occulting pairs, especially those that are a late-type partly obscuring an early-type galaxy which are of interest for the study of dust content of spiral and irregular galaxies. The GAMA survey setup and its autoz automated redshift determination were used to identify candidate blended galaxy spectra from the cross-correlation peaks. We identify 280 blended spectra with a minimum velocity separation of 600 km s−1, of which 104 are lens pair candidates, 71 emission-line-passive pairs, 78 are pairs of emission-line galaxies and 27 are pairs of galaxies with passive spectra. We have visually inspected the candidates in the Sloan Digital Sky Survey (SDSS) and Kilo Degree Survey (KiDS) images. Many blended objects are ellipticals with blue fuzz (Ef in our classification). These latter ‘Ef’ classifications are candidates for possible strong lenses, massive ellipticals with an emission-line galaxy in one or more lensed images. The GAMA lens and occulting galaxy candidate samples are similar in size to those identified in the entire SDSS. This blended spectrum sample stands as a testament of the power of this highly complete, second-largest spectroscopic survey in existence and offers the possibility to expand e.g. strong gravitational lens surveys.

Comments

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society Copyright: 2015. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

https://doi.org/10.1093/mnras/stv589

Original Publication Information

Holwerda, B. W., et al. "Galaxy And Mass Assembly (GAMA) Blended Spectra Catalogue: Strong Galaxy–Galaxy Lens and Occulting Galaxy Pair Candidates." Monthly Notices of the Royal Astronomical Society 449(4): 4277-4287.

ThinkIR Citation

Holwerda, Benne W.; Baldry, I. K.; Alpaslan, M.; Bauer, A. E.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Cluver, M. E.; Conselice, C. J.; Driver, S. P.; Hopkins, A. M.; Jones, D. H.; Lopez-Sanchez, Angel R.; Loveday, J.; Meyer, M. J.; and Moffett, A., "Galaxy And Mass Assembly (GAMA) blended spectra catalogue : strong galaxy–galaxy lens and occulting galaxy pair candidates." (2015). Faculty and Staff Scholarship. 179.
https://ir.library.louisville.edu/faculty/179

DOI

10.1093/mnras/stv589