Constraints on Buchdahl-Inspired Gravity from Future Pulsar Timing near Sgr A*
Abstract
Future pulsar timing observations near Sgr~A* offer a unique probe of gravitational physics in the vicinity of a supermassive black hole. We forecast the ability of such measurements to constrain a Buchdahl-inspired R2 gravity, parameterized by a single deviation parameter ε, using a timing framework that self-consistently integrates orbital dynamics with light-propagation delays and preserves the full timing solution across the observing span. Through Fisher-matrix forecasts for a representative pulsar, we systematically isolate how the precision on ε depends on orbital geometry. We find that shorter orbital periods and higher eccentricities significantly enhance sensitivity, consistent with a substantial contribution from observations near periastron. As a benchmark comparison, we further consider a hypothetical pulsar on an S2-like orbit (Pb=16 yr, e=0.88) and obtain a statistical sensitivity of σε∼ 10−4 within the adopted weak-field, static, and spherically symmetric timing model. This sensitivity is comparable to the natural order-of-magnitude truncation scale of the 1PN expansion and should not be interpreted as a complete forecast for the real Sgr~A* system. Under the adopted idealized assumptions, the characteristic statistical scale is several orders of magnitude below the current S2 95\% confidence interval half-width (|ε|S295%≈ 0.56), though this comparison is heuristic given the differing confidence levels. These trends provide quantitative guidance for target selection and campaign design in future Galactic-center pulsar searches.
Related
- Buchdahl type anisotropic stellar configurations in Rastall gravity
- Prospects for Simultaneously Detecting Long and Short Duration Gravitational Waves from Pulsar Glitches with Current and Future Detectors
- Effects of Eddington-inspired Born-Infeld Gravity on Black Hole Accretion
- Big Bang nucleosynthesis constraints on f(Q,C) gravity
- Inflationary models in a minimally coupled f(R,T) gravity: Constraints from Planck, BICEP/Keck, and ACT
BibTeX
@misc{yan2026constraints,
title = {{Constraints on Buchdahl-Inspired Gravity from Future Pulsar Timing near Sgr A*}},
author = {Jian-Ming Yan and Tao Zhu and Zong-Kuan Guo and Zhao Li},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01153},
eprint = {2609.01153},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01153},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Constraints on Buchdahl-Inspired Gravity from Future Pulsar Timing near Sgr A*
AU - Jian-Ming Yan
AU - Tao Zhu
AU - Zong-Kuan Guo
AU - Zhao Li
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.01153
UR - https://arxiv.org/abs/2609.01153
AB - Future pulsar timing observations near Sgr~A* offer a unique probe of gravitational physics in the vicinity of a supermassive black hole. We forecast the ability of such measurements to constrain a Buchdahl-inspired R^2 gravity, parameterized by a single deviation parameter ε, using a timing framework that self-consistently integrates orbital dynamics with light-propagation delays and preserves the full timing solution across the observing span. Through Fisher-matrix forecasts for a representative pulsar, we systematically isolate how the precision on ε depends on orbital geometry. We find that shorter orbital periods and higher eccentricities significantly enhance sensitivity, consistent with a substantial contribution from observations near periastron. As a benchmark comparison, we further consider a hypothetical pulsar on an S2-like orbit (P_b=16 yr, e=0.88) and obtain a statistical sensitivity of σ_ε∼ 10^−4 within the adopted weak-field, static, and spherically symmetric timing model. This sensitivity is comparable to the natural order-of-magnitude truncation scale of the 1PN expansion and should not be interpreted as a complete forecast for the real Sgr~A* system. Under the adopted idealized assumptions, the characteristic statistical scale is several orders of magnitude below the current S2 95\% confidence interval half-width (|ε|_S2^95%≈ 0.56), though this comparison is heuristic given the differing confidence levels. These trends provide quantitative guidance for target selection and campaign design in future Galactic-center pulsar searches.
ER -