SpectroTranslator: a deep-neural network algorithm to homogenize spectroscopic parameters

Abstract

The emergence of large spectroscopic surveys requires homogenising on the same scale the quantities they measure in order to increase their scientific legacy. We developed the SpectroTranslator, a data-driven deep neural network algorithm that can convert spectroscopic parameters from the base of one survey to another. The algorithm also includes a method to estimate the importance that the various parameters play in the conversion from base A to B. As a showcase, we apply the algorithm to transform effective temperature, surface gravity, metallicity, [Mg/Fe] and los velocity from the base of GALAH into the APOGEE base. We demonstrate the efficiency of the SpectroTranslator algorithm to translate the spectroscopic parameters from one base to another using parameters directly by the survey teams, and are able to achieve a similar performance than previous works that have performed a similar type of conversion but using the full spectrum rather than the spectroscopic parameters, allowing to reduce the computational time, and to use the output of pipelines optimized for each survey. By combining the transformed GALAH catalogue with the APOGEE catalogue, we study the distribution of [Fe/H] and [Mg/Fe] across the Galaxy, and we find that the median distribution of both quantities present a vertical asymmetry at large radii. We attribute it to the recent perturbations generated by the passage of a dwarf galaxy across the disc or by the infall of the Large Magellanic Cloud. Although several aspects still need to be refined, in particular how to deal in an optimal manner with regions of the parameter space meagrely populated by stars in the training sample, the SpectroTranslator already shows its capability and promises to play a crucial role in standardizing various spectroscopic surveys onto a unified basis.

27 pages. Submitted to A&A. Webpage related to the paper: https://research.iac.es/proyecto/spectrotranslator/

References in corpus (24)

• The 2.5 m Telescope of the Sloan Digital Sky Survey
• The Radial Velocity Experiment (RAVE): first data release
• Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
• The Structure of the Milky Way's Bar Outside the Bulge
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
• What is a globular cluster? An observational perspective
• On the Formation of Galactic Thick Disks
• The Gaia-ESO Public Spectroscopic Survey: Motivation, implementation, GIRAFFE data processing, analysis, and final data products
• Gas flow in barred potentials
• Tracing Sagittarius Structure with SDSS and SEGUE Imaging and Spectroscopy
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• StarHorse results for spectroscopic surveys + Gaia DR3: Chrono-chemical populations in the solar vicinity, the genuine thick disk, and young-alpha rich stars
• A radial age gradient in the geometrically thick disk of the Milky Way
• A homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code. I. The Northern clusters
• Overview of the LAMOST survey in the first decade
• The Rich Are Different: Evidence from the RAVE Survey for Stellar Radial Migration
• The GALAH survey: The data reduction pipeline
• A Tale of Two Disks: Mapping the Milky Way with the Final Data Release of APOGEE
• The relationship between mono-abundance and mono-age stellar populations in the Milky Way disk
• Revisiting long-standing puzzles of the Milky Way: the Sun and its vicinity as typical outer disk chemical evolution
• The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14
• The Milky Way's bulge star formation history as constrained from its bimodal chemical abundance distribution
• The Cetus-Palca stream: A disrupted small dwarf galaxy. A prequel to the science possible with WEAVE with precise spectro-photometric distances
• A Bayesian estimation of the Milky Way's circular velocity curve using Gaia DR3

Cited by in corpus (7)

• Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost
• Chronology of our Galaxy from Gaia colour-magnitude diagram fitting (ChronoGal) II. Unveiling the formation and evolution of the kinematically selected Thick and Thin Discs
• The $Hubble$ Missing Globular Cluster Survey. I. Survey overview and the first precise age estimate for ESO452-11 and 2MASS-GC01
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data I. Method validation
• The GALAH Survey: Stellar parameters and abundances for 800,000 Gaia RVS spectra using GALAH DR4 and The Cannon
• The Vertical Structure and Asymmetry of Mg ii-enriched Gas in the Milky Way Disk
• Mining the Kepler Field: Atmospheric Parameters, Bolometric Corrections, and Luminosities