Investigating the Binarity of S0-2: Implications for Its Origins and Robustness as a Probe of the Laws of Gravity around a Supermassive Black Hole

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: Observations Of Bright Stars Near the Galactic Centermentioning

confidence: 99%

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

Borka

J. Cosmol. Astropart. Phys.

2018

“…In Ref. [81] RV residual was formed by subtracting orbital variation of radial velocity. On this residual Lomb-Scargle periodogram was performed with periods sampled between 1 and 150 days, which corresponds to m between 4 × 10 −2 m 22 and 0.63m 22 .…”

Section: Spectroscopic Fingerprints Of Halo Spacetimementioning

confidence: 99%

Motion in time-periodic backgrounds with applications to ultralight dark matter halos at galactic centers

et al. 2018

We consider motion in spherically symmetric but time-dependent backgrounds. This problem is of interest, for example, in the context of ultralight dark matter, where galactic haloes produce a time-dependent and periodic gravitational potential. We study the properties of motion of stars in such spacetimes, for different field strengths and frequency, and including dissipative effects. We show that orbital resonances may occur and that spectroscopic emission lines from stars in these geometries exhibit characteristic, periodic modulation patterns. In addition, we work out a fully relativistic and weak-field description of a special class of time-periodic geometries, that of scalar oscillatons. When applied to the galactic center, our results indicate that the motion of S2-like stars may carry distinguishable observational imprints of ultra-light dark matter. CONTENTS

“…What is the nature of the environment surrounding MBHs? Our own Galactic Centre provides a unique insight into this question [119] as it is close enough to allow for the direct observation of individual stars orbiting our MBH SgrA * (the celebrated S-stars [79]) and even direct imaging of the BH itself [142]. This proximity also provides opportunities for GW observations.…”

Section: An Unparalleled Bird's Eye View Of Sgra *mentioning

confidence: 97%

Unveiling the gravitational universe at μ-Hz frequencies

et al. 2021

We propose a space-based interferometer surveying the gravitational wave (GW) sky in the milli-Hz to μ-Hz frequency range. By the 2040s, the μ-Hz frequency band, bracketed in between the Laser Interferometer Space Antenna (LISA) and pulsar timing arrays, will constitute the largest gap in the coverage of the astrophysically relevant GW spectrum. Yet many outstanding questions related to astrophysics and cosmology are best answered by GW observations in this band. We show that a μ-Hz GW detector will be a truly overarching observatory for the scientific community at large, greatly extending the potential of LISA. Conceived to detect massive black hole binaries from their early inspiral with high signal-to-noise ratio, and low-frequency stellar binaries in the Galaxy, this instrument will be a cornerstone for multimessenger astronomy from the solar neighbourhood to the high-redshift Universe.