2013/12/04 by Christopher Bonnett · 73 citations
Computer Science · Engineering · Physics and Astronomy · #Advanced Image Processing Techniques #Algorithm #Artificial intelligence #Artificial neural network #Astrophysics #CCD and CMOS Imaging Sensors #Computer science #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #Redshift #Sample (material) #Spectral density #Statistical physics #Statistics #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stv230
published in Monthly Notices of the Royal Astronomical Society 449(1), 1043-1056 (Oxford University Press)
arxiv created 2013/12/04 · openalex publication_date 2015/03/20 · arxiv updated 2015/04/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present a novel way of using neural networks (NN) to estimate the redshift distribution of a galaxy sample. We are able to obtain a probability density function (PDF) for each galaxy using a classification NN. The method is applied to 58 714 galaxies in CFHTLenS that have spectroscopic redshifts from DEEP2, VVDS and VIPERS. Using this data, we show that the stacked PDFs give an excellent representation of the true N(z) using information from 5, 4 or 3 photometric bands. We show that the fractional error due to using N(zphot) instead of N(ztruth) is ≤1 per cent on the lensing power spectrum (Pκ) in several tomographic bins. Further, we investigate how well this method performs when few training samples are available and show that in this regime the NN slightly overestimates the N(z) at high z. Finally, the case where the training sample is not representative of the full data set is investigated.