Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
read the original abstract
The highly elliptical, 16-year-period orbit of the star S2 around the massive black hole candidate Sgr A* is a sensitive probe of the gravitational field in the Galactic centre. Near pericentre at 120 AU, ~1400 Schwarzschild radii, the star has an orbital speed of ~7650 km/s, such that the first-order effects of Special and General Relativity have now become detectable with current capabilities. Over the past 26 years, we have monitored the radial velocity and motion on the sky of S2, mainly with the SINFONI and NACO adaptive optics instruments on the ESO Very Large Telescope, and since 2016 and leading up to the pericentre approach in May 2018, with the four-telescope interferometric beam-combiner instrument GRAVITY. From data up to and including pericentre, we robustly detect the combined gravitational redshift and relativistic transverse Doppler effect for S2 of z ~ 200 km/s / c with different statistical analysis methods. When parameterising the post-Newtonian contribution from these effects by a factor f, with f = 0 and f = 1 corresponding to the Newtonian and general relativistic limits, respectively, we find from posterior fitting with different weighting schemes f = 0.90 +/- 0.09 (stat) +\- 0.15 (sys). The S2 data are inconsistent with pure Newtonian dynamics.
This paper has not been read by Pith yet.
Forward citations
Cited by 14 Pith papers
-
Reconstructing the Stripping History of the Sagittarius Stream with Neural Networks
A neural network trained on simulations infers stripping times for Sagittarius stream stars from phase-space data, measuring a 0.3 dex/Gyr metallicity gradient and estimating ages for globular clusters such as Pal 12 ...
-
GRMHD accretion beyond the black hole paradigm: Light from within the shadow
3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central ...
-
The Hubble Missing Globular Clusters Survey IV. Ultra-faint compact satellites of the Milky Way. The case of Koposov 2
Koposov 2 is shown to be an old (13.7 Gyr) star cluster with half-light radius 2.7 pc, absolute magnitude -0.95, and stellar mass 372 solar masses, supporting a star cluster classification over a dwarf galaxy.
-
Black Hole Spectroscopy and Tests of General Relativity with GW250114
GW250114 data confirm the remnant is consistent with a Kerr black hole and bound the dominant quadrupolar mode frequency to within a few percent of the GR prediction, with constraints tighter than prior multi-event catalogs.
-
Dark matter energy exchange in stars orbiting supermassive black holes
Orbit-averaged DM energy exchange for S4714 reaches stellar luminosity at σ_χp ~ 10^{-36} cm² (MeV-GeV) and σ_χe ~ 5×10^{-38} cm² (sub-MeV) for spiked DM profiles.
-
Kick bimodality of neutron stars and mode dependence of their parameters
Classification of pulsars into bimodal kick modes shows low-B objects overabundant in the low-velocity mode, with no high-velocity examples below 10^11 G.
-
Milky Way's warped disc traced by AGB stars
C-rich AGB stars trace the Galactic warp with larger amplitudes than Cepheids at intermediate ages of about 1 Gyr.
-
Constraints on Schwarzschild Black Hole in a Generalized Dehnen-Type $(1,4,\gamma)$ Dark Matter Halo via the S2 Star Orbit around Sgr A$^\star$
Derives perihelion shift equations for S2 star in generalized Schwarzschild-Dehnen BH-DM spacetime and constrains gamma, rho_s, rs via MCMC on Do et al. and Gillessen et al. datasets.
-
Spectroscopy of analogue black holes using simulation-based inference
Simulation-based inference reliably extracts physical parameters from noisy spectra of analogue black holes.
-
Testing the Spacetime Geometry of Sgr A* with the Relativistic Orbit of S2 star
Multiple black-hole and naked-singularity spacetimes are tested against S2 star astrometric and spectroscopic data, showing statistical degeneracy among several models under current observations.
-
Roche limit and stellar disruption in the Simpson--Visser spacetime
Tidal forces in the Simpson-Visser spacetime produce Roche radii for stars that depend on observer type and regularization, with some disruptions occurring outside the event horizon for supermassive black holes.
-
Detectability of secondary images from flares near Sgr A* with mock GRAVITY data
Bayesian fitting to mock GRAVITY data shows robust detection of secondary images from Sgr A* flares requires both an order-of-magnitude larger sample and astrometric uncertainties reduced to 40% of current levels for ...
-
On the impossibility of observational confirmation of black holes
No observational data can confirm the existence of black holes because general relativity imposes fundamental limits on what can be established about them.
-
Testing the nature of dark compact objects: a status report
Current and future observations can test whether dark compact objects are Kerr black holes or exotic alternatives, with null results strengthening the black hole paradigm.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.