1. Measuring redshift and galaxy properties via a multi-task neural net with probabilistic outputs: An application to simulated MOONS spectra
- Author
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Ginolfi, Michele, Mannucci, Filippo, Belfiore, Francesco, Marconi, Alessandro, Boardman, Nicholas, Pozzetti, Lucia, Bolzonella, Micol, Di Teodoro, Enrico, Cresci, Giovanni, Wild, Vivienne, Rodrigues, Myriam, Maiolino, Roberto, Cirasuolo, Michele, and Oliva, Ernesto
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
The era of large-scale astronomical surveys demands innovative approaches for rapid and accurate analysis of extensive spectral data, and a promising direction to address this challenge is offered by artificial intelligence (AI). Here we introduce a new pipeline, M-TOPnet (Multi-Task network Outputting Probabilities), which employs a convolutional neural network (CNN) with residual learning to simultaneously derive redshift and other key physical properties of galaxies from their spectra. Our tool efficiently encodes spectral information into a latent space, employing distinct downstream branches for each physical quantity, thereby benefiting from multi-task learning. Notably, our method handles the redshift output as a probability distribution, allowing for a more refined and robust estimation of this critical parameter. We demonstrate preliminary results using simulated data from the MOONS instrument, which will be soon operating at the ESO/VLT. We highlight the effectiveness of our tool in accurately predicting redshift, stellar mass, and star-formation rate for galaxies at z>~1-3, even for faint sources (m_H >~ 24) where traditional methods often struggle. Through analysis of the output probability distributions, we demonstrate that our pipeline enables robust quality screening of the results, achieving accuracy rates of up to 99% in redshift determination (defined as predictions within |Delta_z| < 0.01 relative to the true redshift) with 8 h exposure spectra, while automatically identifying potentially problematic cases. Our AI pipeline thus emerges as a powerful solution for the upcoming challenges in observational astronomy, combining precision, interpretability, and efficiency, all aspects which are crucial for analysing the massive datasets expected from next-generation instruments., Comment: submitted for publication, comments welcome
- Published
- 2024