Shadows of rotating non-commutative Kiselev black holes: constraints from EHT observations of M87* and Sgr A*
Abstract The Event Horizon Telescope (EHT) imaged black holes M87 $$^*$$ ∗ (angular diameter $$\theta _d = 42 \pm 3\,\upmu \text {as},$$ θ d = 42 ± 3 μ as , mass $$\sim 6.5 \times 10^9\,M_\odot )$$ ∼ 6.5 × 10 9 M ⊙ ) and Sgr A $$^*$$ ∗ $$(\theta _d = 48.7 \pm 7\,\upmu \text {as},$$ ( θ d = 48.7 ± 7...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2025-07-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-025-14510-5 |
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| Summary: | Abstract The Event Horizon Telescope (EHT) imaged black holes M87 $$^*$$ ∗ (angular diameter $$\theta _d = 42 \pm 3\,\upmu \text {as},$$ θ d = 42 ± 3 μ as , mass $$\sim 6.5 \times 10^9\,M_\odot )$$ ∼ 6.5 × 10 9 M ⊙ ) and Sgr A $$^*$$ ∗ $$(\theta _d = 48.7 \pm 7\,\upmu \text {as},$$ ( θ d = 48.7 ± 7 μ as , shadow deviation $$\delta \approx -0.08^{+0.09}_{-0.09}$$ δ ≈ - 0 . 08 - 0.09 + 0.09 (VLTI), $$-0.04^{+0.09}_{-0.10})$$ - 0 . 04 - 0.10 + 0.09 ) (Keck). These observations enable tests of gravity in strong regimes. We propose a rotating non-commutative inspired Kiselev black hole (RNKBH), incorporating dark energy $$(\omega )$$ ( ω ) and non-commutative $$(\Theta )$$ ( Θ ) parameters, extending Kerr solutions. Our analysis reveals that $$\omega = -2/3$$ ω = - 2 / 3 allows larger $$\Theta $$ Θ but requires $$a \ge 0.16M$$ a ≥ 0.16 M to maintain horizons. Shadow calculations show significant deviations from Kerr predictions: for $$\Theta = 0.001-0.005M^2,$$ Θ = 0.001 - 0.005 M 2 , shadows shrink by 8-15% and distortion increases by 20-35% for rapidly spinning $$(a > 0.5M)$$ ( a > 0.5 M ) black holes. The $$\omega = -2/3$$ ω = - 2 / 3 exhibits shadow squeezing near the cosmological horizon. We compute shadow observables and compare them with EHT data. For Sgr A $$^*$$ ∗ $$(50^\circ $$ ( 50 ∘ inclination), the bounds are $$0.001497 \le \Theta \le 0.002868\,M^2$$ 0.001497 ≤ Θ ≤ 0.002868 M 2 at $$a =0.9146$$ a = 0.9146 $$(\omega = -2/3)$$ ( ω = - 2 / 3 ) . For M87 $$^*$$ ∗ $$(17^\circ )$$ ( 17 ∘ ) , $$0 \le \Theta \le 0.004993 \,M^2$$ 0 ≤ Θ ≤ 0.004993 M 2 at $$a=0.0.6167$$ a = 0.0 . 6167 $$(\omega = -2/3)$$ ( ω = - 2 / 3 ) . While EHT cannot yet distinguish RNKBH from Kerr BH, our results highlight its viability as an astrophysical candidate. |
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| ISSN: | 1434-6052 |