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Darth Fader: Analysing galaxy spectra at low signal-to-noise

Published online by Cambridge University Press:  01 July 2015

Adrienne Leonard ,
Daniel P. Machado ,
Filipe B. Abdalla  and
Jean-Luc Starck
Adrienne Leonard*
Affiliation:
Department of Physics and Astronomy, University College London Gower Place, London WC1E 6BT, United Kingdom Laboratoire AIM, UMR CEA-CNRS-Paris 7, IRFU, Service d'Astrophysique CEA Saclay, F-91191 Gif-sur-Yvette CEDEX, France
Daniel P. Machado
Affiliation:
Laboratoire AIM, UMR CEA-CNRS-Paris 7, IRFU, Service d'Astrophysique CEA Saclay, F-91191 Gif-sur-Yvette CEDEX, France
Filipe B. Abdalla
Affiliation:
Department of Physics and Astronomy, University College London Gower Place, London WC1E 6BT, United Kingdom
Jean-Luc Starck
Affiliation:
Laboratoire AIM, UMR CEA-CNRS-Paris 7, IRFU, Service d'Astrophysique CEA Saclay, F-91191 Gif-sur-Yvette CEDEX, France
*
*email: [email protected]
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Abstract

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Spectroscopic redshift surveys are an incredibly valuable tool in cosmology, allowing us to trace the distribution of galaxies as a function of distance and, thus, trace the evolution of structure formation in the Universe. However, estimating the redshifts from spectra with low signal-to-noise is difficult, and such data are often either discarded or require human classification of spectral lines to obtain the galaxy redshift. Darth Fader offers an automated method for estimating the redshifts of galaxies in the low signal-to-noise regime. Using a sophisticated, wavelet-based technique, galaxy spectra can be separated into continuum, line and noise components, and the lines can then be cross-correlated with template spectra in order to estimate the redshifts. Cross-matching of the identified lines then allows for a cleaning of the resulting catalogue, effectively removing the vast majority of erroneous redshift estimates and resulting in a highly pure, highly accurate redshift catalogue. Darth Fader allows us to effectively use low signal-to-noise galaxy spectra, and dramatically reduces the number of human hours required to do this, allowing spectroscopic surveys to probe deeper into the formation history of the Universe.

Keywords

galaxies: distances and redshiftsmethods: data analysistechniques: spectroscopic surveys
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 10 , Symposium S306: Statistical Challenges in 21st Century Cosmology , May 2014 , pp. 72 - 74
Copyright
Copyright © International Astronomical Union 2015 

References

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