The Information Content of Projected Galaxy Fields

Abstract

The power spectrum of the nonlinearly evolved large-scale mass distribution recovers only a minority of the information available on the mass fluctuation amplitude. We investigate the recovery of this information in 2D "slabs" of the mass distribution averaged over ≈ 100 ℎ −1 Mpc along the line of sight, as might be obtained from photometric redshift surveys. We demonstrate a Hamiltonian Monte Carlo (HMC) method to reconstruct the non-Gaussian mass distribution in slabs, under the assumption that the projected field is a point-transformed Gaussian random field, Poisson-sampled by galaxies. When applied to the Quijote 𝑁-body suite at 𝑧 = 1 and at a transverse resolution of 2 ℎ −1 Mpc, the method recovers ∼ 30 times more information than the 2D power spectrum in the well-sampled limit, recovering the Gaussian limit on information. At a more realistic galaxy sampling density of 0.01 ℎ 3 Mpc −3 , shot noise reduces the information gain to a factor of five improvement over the power spectrum at resolutions of 4 ℎ −1 Mpc or smaller.

Cosmology with One Galaxy?

“…However, we do not know what estimator would allow us to extract the maximum amount of information for non-Gaussian density fields, such as the matter and galaxy distribution on nonlinear scales. Quantifying the information content from different estimators is currently a very active area of research (Coulton et al 2019;Li et al 2019;Marques et al 2019;Ajani et al 2020;Allys et al 2020;Banerjee et al 2020;Dai et al 2020;de la Bella et al 2021;Friedrich et al 2020;Giri & Smith 2020;Hahn et al 2020;Villaescusa-Navarro et al 2020;Uhlemann et al 2020;Zhang et al 2020;Banerjee & Abel 2021aBayer et al 2021aBayer et al , 2021bCheng and Ménard 2021;Gualdi et al 2021aGualdi et al , 2021bHahn & Villaescusa-Navarro 2021;Harnois-Déraps et al 2021;Kuruvilla 2021;Kuruvilla & Aghanim 2021;Massara et al 2021;Naidoo et al 2021;Porth et al 2021;Samushia et al 2021;Valogiannis & Dvorkin 2021;Harnois-Déraps et al 2022).…”

Cosmology with one galaxy?

“…However, we do not know what estimator would allow us to extract the maximum amount of information for non-Gaussian density fields, like the matter and galaxy distribution resembles on non-linear scales. Quantifying the information content from different estimators is currently a very active area of research (Villaescusa-Navarro et al 2020;Samushia et al 2021;Gualdi et al 2021a;Kuruvilla & Aghanim 2021;Banerjee et al 2020;Hahn et al 2020;Uhlemann et al 2020;Friedrich et al 2020;Massara et al 2021;Dai et al 2020;Allys et al 2020;Banerjee & Abel 2021a,b;Gualdi et al 2021b,a;Giri & Smith 2020;de la Bella et al 2020;Hahn & Villaescusa-Navarro 2021;Valogiannis & Dvorkin 2021;Kuruvilla 2021;Naidoo et al 2021;Porth et al 2021;Harnois-Déraps et al 2022;Li et al 2019;Coulton et al 2019;Marques et al 2019;Zhang et al 2020;Ajani et al 2020;Harnois-Déraps et al 2021;Cheng & Ménard 2021;Harnois-Déraps et al 2022).…”