ASTROPHYSICAL TESTS OF MODIFIED GRAVITY: CONSTRAINTS FROM DISTANCE INDICATORS IN THE NEARBY UNIVERSE

By B. Jain, Vinu Vikram, Jeremy Sakstein. 2012

172 citations recorded by the source corpus.

We use distance measurements in the nearby universe to carry out new tests of gravity, surpassing other astrophysical tests by over two orders of magnitude for chameleon theories. The three nearby distance indicators—cepheids, tip of the red giant branch (TRGB) stars, and water masers—operate in gravitational fields of widely different strengths. This enables tests of scalar–tensor gravity theories because they are screened from enhanced forces to different extents. Inferred distances from cepheids and TRGB stars are altered (in opposite directions) over a range of chameleon gravity theory parameters well below the sensitivity of cosmological probes. Using published data, we have compared cepheid and TRGB distances in a sample of unscreened dwarf galaxies within 10 Mpc. We use a comparable set of screened galaxies as a control sample. We find no evidence for the order unity force enhancements expected in these theories. Using a two-parameter description of the models (the coupling strength and background field value), we obtain constraints on both the chameleon and symmetron screening scenarios. In particular we show that f(R) models with background field values fR0 above 5 × 10−7 are ruled out at the 95% confidence level. We also compare TRGB and maser distances to the galaxy NGC 4258 as a second test for larger field values. While there are several approximations and caveats in our study, our analysis demonstrates the power of gravity tests in the local universe. We discuss the prospects for additional improved tests with future observations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/5a3472f4e23eddf0aee3ffdcc21e7ca6f26e8cf8

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Citations in the corpus

LSST: From Science Drivers to Reference Design and Anticipated Data Products (2008, background): “…and cluster counting), LSST data can reveal whether the recent cosmic acceleration is due to dark energy or modified gravity (Lue, Scoccimarro & Starkman 2004; Knox, Song & Tyson 2006; Ishak, Upadhye & Spergel 2006; Jain & Zhang 2008; Oguri & Takada 2011; Jain et al. 2013; Weinberg et al. 2013).”
Beyond the Cosmological Standard Model (2014, unknown): “Measurements of these properties within screened and unscreened galaxies then provide tests of gravity: the two distance indicators should agree for screened galaxies but not for unscreened galaxies [859].”
Probing dark energy with atom interferometry (2014, background): “For the upper bound we take the reduced Planck mass MP ' 2×1018 GeV, motivated by laboratory and astrophysical tests of gravity [8, 15, 16, 18], and by the lack of clarity about physics above the Planck scale.”
Cosmological tests of modified gravity (2015, methodology): “This modification of the stellar structure was used to put a strong constraint on the chameleon mechanism [345].”
Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces (2016, background): “Alternatively, limits on chameleon models can be placed by searching for differences between samples of similar objects in screened and unscreened environments (e.g., dwarf galaxies – Jain et al. 2013; Vikram et al. 2013) and constraints of | fR0| <∼ 10−7 are obtained.”
The DESI Experiment Part I: Science,Targeting, and Survey Design (2016, background): “Finally, the more detailed map will allow tests of screening theories on smaller scales [70, 71], in which one considers the response of individual galaxies to the predicted gravitational field.”