Euclid preparation. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples
Abstract
Future data provided by the Euclid mission will allow us to better understand the cosmic history of the Universe. A metric of its performance is the figure-of-merit (FoM) of dark energy, usually estimated with Fisher forecasts. The expected FoM has previously been estimated taking into account the two main probes of Euclid, namely the three-dimensional clustering of the spectroscopic galaxy sample, and the so-called 3x2pt signal from the photometric sample (i.e., the weak lensing signal, the galaxy clustering, and their cross-correlation). So far, these two probes have been treated as independent. In this paper, we introduce a new observable given by the ratio of the (angular) two-point correlation function of galaxies from the two surveys. For identical (normalised) selection functions, this observable is unaffected by sampling noise, and its variance is solely controlled by Poisson noise. We present forecasts for Euclid where this multi-tracer method is applied and is particularly relevant because the two surveys will cover the same area of the sky. This method allows for the exploitation of the combination of the spectroscopic and photometric samples. When the correlation between this new observable and the other probes is not taken into account, a significant gain is obtained in the FoM, as well as in the constraints on other cosmological parameters. The benefit is more pronounced for a commonly investigated modified gravity model, namely the parametrisation of the growth factor. However, the correlation between the different probes is found to be significant and hence the actual gain is uncertain. We present various strategies for circumventing this issue and still extract useful information from the new observable.
Keywords
Cite
@article{arxiv.2404.12157,
title = {Euclid preparation. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples},
author = {Euclid Collaboration and F. Dournac and A. Blanchard and S. Ilić and B. Lamine and I. Tutusaus and A. Amara and S. Andreon and N. Auricchio and H. Aussel and M. Baldi and S. Bardelli and C. Bodendorf and D. Bonino and E. Branchini and S. Brau-Nogue and M. Brescia and J. Brinchmann and S. Camera and V. Capobianco and J. Carretero and S. Casas and M. Castellano and S. Cavuoti and A. Cimatti 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 A. M. Di Giorgio and J. Dinis and M. Douspis and F. Dubath and X. Dupac and S. Dusini and A. Ealet and M. Farina and S. Farrens and S. Ferriol and M. Frailis and E. Franceschi and S. Galeotta and W. Gillard and B. Gillis and C. Giocoli and B. R. Granett and A. Grazian and F. Grupp and S. V. H. Haugan and W. Holmes and I. Hook and F. Hormuth and A. Hornstrup and P. Hudelot and K. Jahnke and E. Keihänen and S. Kermiche and A. Kiessling and M. Kilbinger and B. Kubik and M. Kümmel and M. Kunz and H. Kurki-Suonio and S. Ligori and P. B. Lilje and V. Lindholm and I. Lloro and D. Maino and E. Maiorano and O. Mansutti and O. Marggraf and K. Markovic and N. Martinet and F. Marulli and R. Massey and S. Maurogordato and E. Medinaceli and S. Mei and Y. Mellier and M. Meneghetti and E. Merlin and G. Meylan and M. Moresco and L. Moscardini and E. Munari and S. -M. Niemi and J. W. Nightingale 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 L. Pozzetti and F. Raison and R. Rebolo and A. Renzi and J. Rhodes and G. Riccio and E. Romelli and M. Roncarelli and E. Rossetti and R. Saglia and D. Sapone and P. Schneider and A. Secroun and G. Seidel and M. Seiffert and S. Serrano and C. Sirignano and G. Sirri and L. Stanco and C. Surace and P. Tallada-Crespí and D. Tavagnacco and A. N. Taylor and I. Tereno and R. Toledo-Moreo and F. Torradeflot and E. A. Valentijn and L. Valenziano and T. Vassallo and A. Veropalumbo and Y. Wang and A. Zacchei and G. Zamorani and J. Zoubian and E. Zucca and A. Biviano and M. Bolzonella and A. Boucaud and E. Bozzo and C. Burigana and C. Colodro-Conde and G. De Lucia and D. Di Ferdinando and J. A. Escartin Vigo and R. Farinelli and J. Gracia-Carpio and G. Mainetti and M. Martinelli and N. Mauri and C. Neissner and Z. Sakr and V. Scottez and M. Tenti and M. Viel and M. Wiesmann and Y. Akrami and V. Allevato and S. Anselmi and C. Baccigalupi and A. Balaguera-Antolinez and M. Ballardini and L. Blot and S. Borgani and S. Bruton and R. Cabanac and A. Calabro and G. Canas-Herrera and A. Cappi and C. S. Carvalho and G. Castignani and T. Castro and K. C. Chambers and S. Contarini and A. R. Cooray and J. Coupon and S. Davini and B. De Caro and S. de la Torre and G. Desprez and A. Díaz-Sánchez and S. Di Domizio and H. Dole and S. Escoffier and A. G. Ferrari and P. G. Ferreira and I. Ferrero and F. Finelli and L. Gabarra and K. Ganga and J. García-Bellido and E. Gaztanaga and F. Giacomini and G. Gozaliasl and H. Hildebrandt and A. Jimenez Munoz and J. J. E. Kajava and V. Kansal and D. Karagiannis and C. C. Kirkpatrick and L. Legrand and G. Libet and A. Loureiro and J. Macias-Perez and G. Maggio and M. Magliocchetti and F. Mannucci and R. Maoli and C. J. A. P. Martins and S. Matthew and L. Maurin and R. B. Metcalf and M. Migliaccio and P. Monaco and C. Moretti and G. Morgante and S. Nadathur and Nicholas A. Walton and L. Patrizii and A. Pezzotta and M. Pöntinen and V. Popa and C. Porciani and D. Potter and I. Risso and P. -F. Rocci and M. Sahlén and A. G. Sánchez and J. A. Schewtschenko and A. Schneider and E. Sefusatti and M. Sereno and J. Steinwagner and N. Tessore and G. Testera and R. Teyssier and S. Toft and S. Tosi and A. Troja and M. Tucci and J. Valiviita and D. Vergani and G. Verza},
journal= {arXiv preprint arXiv:2404.12157},
year = {2024}
}
Comments
16 pages, 7 figures, submitted to A&A