Different Ways to Estimate Graviton Mass

Borka

J. Cosmol. Astropart. Phys.

2018

Recently, the LIGO-Virgo collaboration discovered gravitational waves and in their first publication on the subject the authors also presented a graviton mass constraint as m g < 1.2 × 10 −22 eV [1] (see also more details in a complimentary paper [2]). In our previous papers we considered constraints on Yukawa gravity parameters [3] and on graviton mass from analysis of the trajectory of S2 star near the Galactic Center [4]. In the paper we analyze a potential to reduce upper bounds for graviton mass with future observational data on trajectories of bright stars near the Galactic Center. Since gravitational potentials are different for these two cases, expressions for relativistic advance for general relativity and Yukawa potential are different functions on eccentricity and semimajor axis, it gives an opportunity to improve current estimates of graviton mass with future observational facilities. In our considerations of an improvement potential for a graviton mass estimate we adopt a conservative strategy and assume that trajectories of bright stars and their apocenter advance will be described with general relativity expressions and it gives opportunities to improve graviton mass constraints. In contrast with our previous studies, where we present current constraints on parameters of Yukawa gravity [3] and graviton mass [4] from observations of S2 star, in the paper we express expectations to improve current constraints for graviton mass, assuming the GR predictions about apocenter shifts will be confirmed with future observations. We concluded that if future observations of bright star orbits during around fifty years will confirm GR predictions about apocenter shifts of bright star orbits it give an opportunity to constrain a graviton mass at a level around 5 × 10 −23 eV or slightly better than current estimates obtained with LIGO observations.

Section: Observational Constraints On Graviton Mass From Observationsmentioning

confidence: 78%

Constraining the range of Yukawa gravity interaction from S2 star orbits III: improvement expectations for graviton mass bounds

Borka

J. Cosmol. Astropart. Phys.

2018

“…[2016] also use a similar phenomenological consequence of massive gravity and show that an analysis of bright star trajectories near the Galactic Center could bound the graviton mass. They found the upper bound for graviton mass from their work to be m g < 2.9 × 10 −21 eV within 90% confidence level [46,47].…”

Section: Introductionmentioning

confidence: 82%

Bounds on graviton mass using weak lensing and SZ effect in galaxy clusters

et al. 2018

In General Relativity (GR), the graviton is massless. However, a common feature in several theoretical alternatives of GR is a non-zero mass for the graviton. These theories can be described as massive gravity theories. Despite many theoretical complexities in these theories, on phenomenological grounds the implications of massive gravity have been widely used to put bounds on graviton mass. One of the generic implications of giving a mass to the graviton is that the gravitational potential will follow a Yukawa-like fall off. We use this feature of massive gravity theories to probe the mass of graviton by using the largest gravitationally bound objects, namely galaxy clusters. In this work, we use the mass estimates of galaxy clusters measured at various cosmologically defined radial distances measured via weak lensing (WL) and Sunyaev-Zeldovich (SZ) effect. We also uses the model independent values of Hubble parameter H(z) smoothed by a non-parametric method, Gaussian process. Within 1σ confidence region, we obtain the mass of graviton m g < 5.9 × 10 −30 eV with the corresponding Compton length scale λ g > 6.82 Mpc from weak lensing and m g < 8.31 × 10 −30 eV with λ g > 5.012 Mpc from SZ effect. This analysis improves the upper bound on graviton mass obtained earlier from galaxy clusters.

“…The LIGO -Virgo collaboration together with its partner groups observing the same astronomical sources with different facilities found that constraints on speed of gravitational waves from binary [113]. Since graviton energy is E = hf , therefore, assuming a typical LIGO frequency range f ∈ (10, 100), from the dispersion relation one could obtain a graviton mass estimate m g < 3 × (10 −21 − 10 −20 ) eV which is a weaker estimates than previous ones obtained from binary black hole signals detected by the LIGO team [114]. In the case of massive graviton, one could use Yukawa gravitational potential in a form ∝ r −1 exp(−r/λ g ), and in this case a lower bound for Compton wavelength λ g of the graviton is connected with an upper bound of its mass…”

Section: Massive Graviton Constraintsmentioning

confidence: 99%

Tests of gravity theories with Galactic Center observations

Zakharov

2019

Int. J. Mod. Phys. D

Self Cite

An active stage of relativistic astrophysics started in 1963 since in this year, quasars were discovered, Kerr solution has been found and the first Texas Symposium on Relativistic Astrophysics was organized in Dallas. Five years later, in 1967 were discovered and their model as rotating neutron stars has been proposed, meanwhile J. A. Wheeler claimed that Kerr and Schwarzschild vacuum solutions of Einstein equations provide an efficient approach for astronomical objects with different masses. Wheeler suggested to call these objects black holes. Neutron stars were observed in different spectral band of electromagnetic radiation. In addition, a neutrino signal has been found for SN1987A. Therefore, multi-messenger astronomy demonstrated its efficiency for decades even before observations of the first gravitational radiation sources. However, usually, one has only manifestations of black holes in a weak gravitational field limit and sometimes a model with a black hole could be substituted with an alternative approach which very often looks much less natural, however, it is necessary to find observational evidences to reject such an alternative model. At the moment only a few astronomical signatures for strong gravitational field are found, including a shape of relativistic iron Kα line, size and shape of shadows near black holes at the Galactic Centers and M87, trajectories of bright stars near the Galactic Center. After two observational runs the LIGO-Virgo collaboration provided a confirmation for an presence of mergers for ten binary black holes and one binary neutron star system where gravitational wave signals were found. In addition, in last years a remarkable progress has been reached in a development of observational facilities to investigate a gravitational potential, for instance, a number of telescopes operating in the Event Horizon Telescope network is increasing and accuracy of a shadow reconstruction near the Galactic Center is improving, meanwhile largest VLT, Keck telescopes with adaptive optics and especially, GRAVITY facilities observe bright IR stars at the Galactic Center with a perfecting accuracy. More options for precision observations of bright stars will be available with creating extremely large telescopes TMT and E-ELT. It is clear that the Galactic Center (Sgr A * ) is a specific objects for observations. Our Solar system is located at a distance around 8 kpc from January 25, 2019 1:28 WSPC/INSTRUCTION FILE Zakharov˙ICPPA˙2018˙IJMPD˙arxiv 2 Alexander F. Zakharov the Galactic Center (GC). Earlier, theorists proposed a number of different models including exotic ones for GC such as boson star, fermion ball, neutrino ball, a cluster of neutron stars. Later, some of these models are ruled out or essentially constrained with consequent observations and theoretical considerations. Currently, a supermassive black hole with mass around 4 × 10 6 M ⊙ is the most natural model for GC. Using results of observations for trajectories of bright stars in paper [1] the authors got a graviton mass constra...