Euclid preparation. Predicting star-forming galaxy scaling relations with the spectral stacking code SpectraPyle
Abstract
We introduce SpectraPyle, a versatile spectral stacking pipeline developed for the Euclid mission's NISP spectroscopic surveys, aimed at extracting faint emission lines and spectral features from large galaxy samples in the Wide and Deep Surveys. Designed for computational efficiency and flexible configuration, SpectraPyle supports the processing of extensive datasets critical to Euclid's non-cosmological science goals. We validate the pipeline using simulated spectra processed to match Euclid's expected final data quality. Stacking enables robust recovery of key emission lines, including Halpha, Hbeta, [O III], and [N II], below individual detection limits. However, the measurement of galaxy properties such as star formation rate, dust attenuation, and gas-phase metallicity are biased at stellar mass below log10(M*/Msol) ~ 9 due to the flux-limited nature of Euclid spectroscopic samples, which cannot be overcome by stacking. The SFR-stellar mass relation of the parent sample is recovered reliably only in the Deep survey for log10(M*/Msol) > 10, whereas the metallicity-mass relation is recovered more accurately over a wider mass range. These limitations are caused by the increased fraction of redshift measurement errors at lower masses and fluxes. We examine the impact of residual redshift contaminants that arises from misidentified emission lines and noise spikes, on stacked spectra. Even after stringent quality selections, low-level contamination (< 6%) has minimal impact on line fluxes due to the systematically weaker emission of contaminants. Percentile-based analysis of stacked spectra provides a sensitive diagnostic for detecting contamination via coherent spurious features at characteristic wavelengths. While our simulations include most instrumental effects, real Euclid data will require further refinement of contamination mitigation strategies.
Keywords
Cite
@article{arxiv.2509.16120,
title = {Euclid preparation. Predicting star-forming galaxy scaling relations with the spectral stacking code SpectraPyle},
author = {Euclid Collaboration and S. Quai and L. Pozzetti and M. Talia and C. Mancini and P. Cassata and L. Gabarra and V. Le Brun and M. Bolzonella and E. Rossetti and S. Kruk and B. R. Granett and C. Scarlata and M. Moresco and G. Zamorani and D. Vergani and X. Lopez Lopez and A. Enia and E. Daddi and V. Allevato and I. A. Zinchenko and M. Magliocchetti and M. Siudek and L. Bisigello and G. De Lucia and H. J. Dickinson and E. Lusso and M. Hirschmann and A. Cimatti and L. Wang and J. G. Sorce and N. Aghanim and A. Amara and S. Andreon and N. Auricchio and C. Baccigalupi and M. Baldi and S. Bardelli and A. Biviano and E. Branchini and M. Brescia and J. Brinchmann and S. Camera and G. Cañas-Herrera and V. Capobianco and C. Carbone and J. Carretero and S. Casas and M. Castellano and G. Castignani and S. Cavuoti and K. C. Chambers and C. Colodro-Conde and G. Congedo and C. J. Conselice and L. Conversi and Y. Copin and F. Courbin and H. M. Courtois and A. Da Silva and H. Degaudenzi and S. de la Torre and H. Dole and M. Douspis and F. Dubath and X. Dupac and S. Dusini and A. Ealet and S. Escoffier and M. Farina and R. Farinelli and F. Faustini and S. Ferriol and F. Finelli and N. Fourmanoit and M. Frailis and E. Franceschi and S. Galeotta and K. George and W. Gillard and B. Gillis and C. Giocoli and J. Gracia-Carpio and A. Grazian and F. Grupp and L. Guzzo and S. V. H. Haugan and W. Holmes and I. M. Hook and F. Hormuth and A. Hornstrup and P. Hudelot and K. Jahnke and M. Jhabvala and B. Joachimi and E. Keihänen and S. Kermiche and A. Kiessling and B. Kubik and M. Kümmel and M. Kunz and H. Kurki-Suonio and A. M. C. Le Brun and S. Ligori and P. B. Lilje and V. Lindholm and I. Lloro and G. Mainetti and D. Maino and E. Maiorano and O. Mansutti and S. Marcin and O. Marggraf and M. Martinelli and N. Martinet and F. Marulli and R. J. Massey and E. Medinaceli and S. Mei and M. Melchior and Y. Mellier and M. Meneghetti and E. Merlin and G. Meylan and A. Mora and L. Moscardini and C. Neissner and S. -M. Niemi and C. Padilla and S. Paltani and F. Pasian and K. Pedersen and W. J. Percival and V. Pettorino and S. Pires and G. Polenta and M. Poncet and L. A. Popa and F. Raison and R. Rebolo and A. Renzi and J. Rhodes and G. Riccio and E. Romelli and M. Roncarelli and R. Saglia and Z. Sakr and A. G. Sánchez and D. Sapone and B. Sartoris and P. Schneider and T. Schrabback and M. Scodeggio and A. Secroun and E. Sefusatti and G. Seidel and M. Seiffert and S. Serrano and P. Simon and C. Sirignano and G. Sirri and L. Stanco and J. -L. Starck and J. Steinwagner and P. Tallada-Crespí and D. Tavagnacco and A. N. Taylor and H. I. Teplitz and I. Tereno and S. Toft and R. Toledo-Moreo and F. Torradeflot and I. Tutusaus and L. Valenziano and J. Valiviita and T. Vassallo and G. Verdoes Kleijn and A. Veropalumbo and D. Vibert and Y. Wang and J. Weller and E. Zucca and M. Ballardini and E. Bozzo and C. Burigana and R. Cabanac and A. Cappi and D. Di Ferdinando and J. A. Escartin Vigo and M. Huertas-Company and J. Martín-Fleitas and S. Matthew and N. Mauri and R. B. Metcalf and A. Pezzotta and M. Pöntinen and C. Porciani and I. Risso and V. Scottez and M. Sereno and M. Tenti and M. Viel and M. Wiesmann and Y. Akrami and I. T. Andika and S. Anselmi and M. Archidiacono and F. Atrio-Barandela and P. Bergamini and D. Bertacca and M. Bethermin and A. Blanchard and L. Blot and S. Borgani and M. L. Brown and S. Bruton and A. Calabro and B. Camacho Quevedo and F. Caro and C. S. Carvalho and T. Castro and F. Cogato and S. Conseil and T. Contini and A. R. Cooray and O. Cucciati and S. Davini and G. Desprez and A. Díaz-Sánchez and J. J. Diaz and S. Di Domizio and J. M. Diego and Y. Fang and A. G. Ferrari and A. Finoguenov and A. Fontana and F. Fontanot and A. Franco and K. Ganga and J. García-Bellido and T. Gasparetto and V. Gautard and E. Gaztanaga and F. Giacomini and F. Gianotti and G. Gozaliasl and M. Guidi and C. M. Gutierrez and A. Hall and S. Hemmati and C. Hernández-Monteagudo and H. Hildebrandt and J. Hjorth and J. J. E. Kajava and Y. Kang and V. Kansal and D. Karagiannis and K. Kiiveri and C. C. Kirkpatrick and L. Legrand and M. Lembo and F. Lepori and G. Leroy and G. F. Lesci and J. Lesgourgues and L. Leuzzi and T. I. Liaudat and S. J. Liu and A. Loureiro and J. Macias-Perez and G. Maggio and F. Mannucci and R. Maoli and C. J. A. P. Martins and L. Maurin and M. Miluzio and P. Monaco and C. Moretti and G. Morgante and S. Nadathur and K. Naidoo and A. Navarro-Alsina and S. Nesseris and F. Passalacqua and K. Paterson and L. Patrizii and A. Pisani and D. Potter and M. Radovich and P. -F. Rocci and G. Rodighiero and S. Sacquegna and M. Sahlén and D. B. Sanders and E. Sarpa and A. Schneider and D. Sciotti and E. Sellentin and F. Shankar and L. C. Smith and K. Tanidis and C. Tao and G. Testera and R. Teyssier and S. Tosi and A. Troja and M. Tucci and C. Valieri and A. Venhola and G. Verza and P. Vielzeuf and N. A. Walton},
journal= {arXiv preprint arXiv:2509.16120},
year = {2026}
}
Comments
17 pages, 21 figures, Submitted to A&A