The first analytical expression to estimate photometric redshifts suggested by a machine

Author(s)

Krone-Martins, A. ^[1] ; Ishida, E. E. O. ^{[2, 3]} ; de Souza, R. S. ^{[4, 5]}

Affiliation

^[1] Univ Lisbon, Fac Ciencias, SIM, P-1749016 Lisbon - Portugal

^[2] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo, SP - Brazil

^[3] Max Planck Inst Astrophys, D-85748 Garching - Germany

^[4] Korea Astron & Space Sci Inst, Taejon 305348 - South Korea

^[5] MTA Eotvos Univ, EIRSA Lendulet Astrophys Res Grp, H-1117 Budapest - Hungary

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 443, n. 1, p. L34-L38, SEP 1 2014.
• Web of Science Citations: 10

Abstract

We report the first analytical expression purely constructed by a machine to determine photometric redshifts (z(phot)) of galaxies. A simple and reliable functional form is derived using 41 214 galaxies from the Sloan Digital Sky Survey Data Release 10 (SDSS-DR10) spectroscopic sample. The method automatically dropped the u and z bands, relying only on g, r and i for the final solution. Applying this expression to other 1417 181 SDSS-DR10 galaxies, with measured spectroscopic redshifts (z(spec)), we achieved a mean <(z(phot) - z(spec))/(1 + z(spec))> less than or similar to 0.0086 and a scatter sigma(z(phot-zspec))/(1+ (zspec)) less than or similar to 0.045 when averaged up to z less than or similar to 1.0. The method was also applied to the PHAT0 data set, confirming the competitiveness of our results when faced with other methods from the literature. This is the first use of symbolic regression in cosmology, representing a leap forward in astronomy-data-mining connection. (AU)

• FAPESP's process: 11/09525-3 - Analysis of type IA supernovae in wide-field galaxy surveys
• Grantee: Emille Eugenia de Oliveira Ishida
• Support Opportunities: Scholarships in Brazil - Post-Doctoral