Astrophysical tests of modified gravity: Constraints from distance indicators in the nearby universe

Journal Article · Tue Dec 10 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/779/1/39· OSTI ID:22348509

Jain, Bhuvnesh; Vikram, Vinu ^[1]; Sakstein, Jeremy ^[2]

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1. Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States)
2. Department of Applied Mathematics and Theoretical Physics, Cambridge CB3 0WA (United Kingdom)

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 f {sub R0} above 5 × 10{sup –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.

• OSTI ID: 22348509
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 779; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
APPROXIMATIONS
ASTROPHYSICS
CEPHEIDS
COMPARATIVE EVALUATIONS
COSMOLOGY
COUPLING
GALAXIES
GRAVITATIONAL FIELDS
LIMITING VALUES
MASERS
SCREENING
SENSITIVITY
UNIVERSE
WATER