A Finely-Binned Measurement of the Connected Even-Parity Galaxy 4-Point Correlation Function of DESI Year 1 Luminous Red Galaxies

William Ortolá Leonard; Alex Krolewski; Zachary Slepian; Alessandro Greco; Simon May; J. Aguilar; S. Ahlen; O. Alves; A. Aviles; F. Beutler; D. Bianchi; D. Brooks; A. Carnero Rosell; T. Claybaugh; A. de la Macorra; Biprateep Dey; S. Ferraro; J. E. Forero-Romero; E. Gaztañaga; Satya Gontcho A Gontcho; G. Gutierrez; K. Honscheid; D. Huterer; M. Ishak; S. Juneau; T. Karim; R. Kehoe; D. Kirkby; O. Lahav; M. Landriau; L. Le Guillou; M. Manera; A. Meisner; R. Miquel; J. A. Newman; E. Paillas; W. J. Percival; F. Prada; I. Pérez-Ràfols; C. Ravoux; R. Ruggeri; L. Samushia; E. Sanchez; C. Saulder; D. Schlegel; J. H. Silber; M. Siudek; G. Tarlé; B. A. Weaver

arXiv · 2609.09340

A Finely-Binned Measurement of the Connected Even-Parity Galaxy 4-Point Correlation Function of DESI Year 1 Luminous Red Galaxies

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Abstract

We present the connected even-parity galaxy 4-Point Correlation Function (4PCF) of DESI Year 1 (Y1) Luminous Red Galaxies (LRGs). This is one of the first measurements of the connected 4PCF on data, and shows a clear detection at $\sim$12 to 17$\sigma$ in the full-sky analysis. We test the robustness of the signal by varying three factors: hemisphere (north vs. south), redshift range (either the full range $0.4 < z < 1.1$ or the higher-number-density interval $0.4 < z < 0.8$), and sample completeness (the full sample vs. only the most complete regions within the number density-motivated cut). Finally, we cross-correlate different patches that are spatially well-separated, and thus should have largely independent noise. This approach, at leading order, is able to remove mismatch between the covariance matrix of the data and that of the mocks; however, in certain cases at the cost of sensitivity. We find $\sim$15$\sigma$ evidence for an even-parity 4PCF in this approach. Overall, the studies of the 4PCF presented here probe sensitively any mismatch between mock catalogs and data, and also open up the prospect of fitting a model, constraining cosmological parameters and galaxy biases, and searching for Baryon Acoustic Oscillation (BAO) features.

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William Ortolá Leonard, Alex Krolewski, Zachary Slepian, Alessandro Greco, Simon May, J. Aguilar, S. Ahlen, O. Alves, A. Aviles, F. Beutler, D. Bianchi, D. Brooks, A. Carnero Rosell, T. Claybaugh, A. de la Macorra, Biprateep Dey, S. Ferraro, J. E. Forero-Romero, E. Gaztañaga, Satya Gontcho A Gontcho, G. Gutierrez, K. Honscheid, D. Huterer, M. Ishak, S. Juneau, T. Karim, R. Kehoe, D. Kirkby, O. Lahav, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. A. Newman, E. Paillas, W. J. Percival, F. Prada, I. Pérez-Ràfols, C. Ravoux, R. Ruggeri, L. Samushia, E. Sanchez, C. Saulder, D. Schlegel, J. H. Silber, M. Siudek, G. Tarlé, B. A. Weaver. 2026-09-08. A Finely-Binned Measurement of the Connected Even-Parity Galaxy 4-Point Correlation Function of DESI Year 1 Luminous Red Galaxies. https://arxiv.org/abs/2609.09340

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