Subpercent accurate fitting of modified gravity growth

Mikhail Denissenya, Eric V. Linder

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We investigate how to recognize and fit gravitational modifications to linear growth observables at redshifts z≲3, complementing our previous work establishing that a single parameter could treat modifications at z≲3. We establish subpercent accurate fits to the redshift space distortion observable fσ8(a) using two parameters binned in redshift, testing the results for modifications with time dependence that rises, falls, is nonmonotonic, is multipeaked, and corresponds to f(R) and braneworld gravity. The residuals are then propagated to cosmological parameter biases for DESI observations, and found to cause a shift in the dark energy joint confidence contour by less than the equivalent of ∼0.1σ. The proposed 2-3 parameter modified gravity description also can reveal physical characteristics of the underlying theory.

Original languageEnglish
Article number052
JournalJournal of Cosmology and Astroparticle Physics
Issue number11
Publication statusPublished - Nov 29 2017
Externally publishedYes


  • galaxy clustering
  • modified gravity
  • redshift surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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