Projecting unequal time fields and correlators of large scale structure

Steele, Theodore; Raccanelli, Alvise; Vlah, Zvonimir (2025) Projecting unequal time fields and correlators of large scale structure. Physical Review D, 112 (6). ISSN 2470-0010

PDF - Published Version - article Available under License Creative Commons Attribution. Download (963kB)

Abstract

Many large scale structure surveys sort their observations into redshift bins and treat every tracer as being located at the mean redshift of its bin, a treatment which we refer to as the equal time approximation. Recently, a new method was developed which allows for the estimation and correction of errors introduced by this approximation, which we refer to as the unequal time correlator-level projection. For single tracer power spectra, corrections arise at second order and above in a series expansion, with first order terms surviving only in multitracer analyses. In this paper we develop a new method which we refer to as the unequal time field level projection. This formalism projects the fields individually onto the celestial sphere, displaced from individual reference times, before defining their correlators. This method introduces new, first order correction terms even in the case of single tracer power spectra. Specifically, new first order terms are introduced which apply to both cross-bin and single bin correlators. All of these new corrections originate with derivatives over combinations of a delta function, a cross-bin phase term, and the power spectrum itself and stem from the introduction of two unequal time Fourier transforms into the analysis. We analyze these corrections in the context of a linearly biased power spectrum divided between two redshift bins and find that they can lead to nontrivial corrections, particularly to cross-bin correlators. We also show that these terms can be replicated by appropriately extending the correlator-level analysis to include a second Fourier transform which allows for a full redshift bin integration.

Item Type:	Article
Uncontrolled Keywords:	anthropic considerations; cosmological parameters; gravitational lenses
Subjects:	NATURAL SCIENCES > Physics > Physics of Elementary Particles and Fields NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Divisions:	Theoretical Physics Division
Depositing User:	Zvonimir Vlah
Date Deposited:	09 Jan 2026 11:08
URI:	http://fulir.irb.hr/id/eprint/10772
DOI:	10.1103/mfzt-hn37

Actions (login required)

View Item