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The high-mass (M ≳ 30M<SUB>⊙</SUB>) black holes (BHs) from the gravitational-wave (GW) observations of LIGO and Virgo came as a surprise to many astronomers. While the collapse of metal-poor massive stars could produce such BHs, gravitational lensing has been invoked to explain their high masses. Broadhurst, Diego, and Smoot (henceforth BDS) argued that the mass distribution of BHs in coalescing binaries is very similar to that of the galactic BHs, and the inferred high masses are the result of neglecting the lensing magnification. They also proposed a redshift distribution of binary BH (BBH) mergers to explain the observed LIGO-Virgo mass distribution. We ask whether such a model is consistent with different aspects of the GW observations: (1) the observed number of BBH mergers, (2) the distribution of their redshifted total mass and apparent luminosity distance, (3) the nondetection of strongly lensed events, and (4) the nonobservation of the stochastic GW background. By simulating lensed BBH mergers with the BDS model and comparing them with observations, we conclude that no choice of BDS model parameters is consistent with all aspects of the observations. Lensing magnification is not a viable explanation for the high-mass BHs discovered by LIGO and Virgo.

Timelike orbits in curved spacetimes encode intrinsic information about the background geometry and serve as critical probes for investigating gravitational theories and source distributions. In this study, we investigate strictly closed timelike orbits within a Schwarzschild spacetime embedded in a Dehnen-type dark matter halo. By solving the geodesic equations, we identify various configurations of these closed orbits and simulate their corresponding gravitational waves and electromagnetic light curves. Our findings reveal that the morphology of closed orbits is primarily governed by the ratio of the azimuthal period to the radial period. Notably, dark matter halo parameters such as the core scale and density parameters exert a significant amplification effect on the orbital scale, which further induces a discernible phase lag in the gravitational wave signals. Furthermore, within a specific parameter space, we discover a linear relationship between the number of peaks in the light curves and the number of orbital leaves. From a theoretical perspective, these findings reveal the multimessenger signatures of closed orbits, which may provide a potential theoretical foundation for establishing a connection between orbital dynamics and the surrounding dark matter environment.

We computethe transmission properties of electromagnetic (EM), gravitational wave, and static gravitational perturbations through geometric throats in spherically symmetric spacetimes. On the ultrastatic Ellis-Bronnikov background, decomposition of the four-dimensional Maxwell equations into vector spherical harmonics yields an effective Schrödinger problem with centrifugal barrier <inline-formula><mml:math><mml:msubsup><mml:mi>V</mml:mi><mml:mo>ℓ</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mi>EM</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:msubsup><mml:mo>=</mml:mo><mml:mo>ℓ</mml:mo><mml:mo>(</mml:mo><mml:mo>ℓ</mml:mo><mml:mo>+</mml:mo><mml:mn>1</mml:mn><mml:mo>)</mml:mo><mml:mo>/</mml:mo><mml:mo>(</mml:mo><mml:msup><mml:mi>σ</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:mo>+</mml:mo><mml:msubsup><mml:mi>r</mml:mi><mml:mn>0</mml:mn><mml:mn>2</mml:mn></mml:msubsup><mml:mo>)</mml:mo></mml:math></inline-formula> peaked at the throat. For the lowest physical EM mode (<inline-formula><mml:math><mml:mo>ℓ</mml:mo><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:math></inline-formula>), frequencies below the barrier-top frequency <inline-formula><mml:math><mml:msub><mml:mi>ω</mml:mi><mml:mi>max</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:msqrt><mml:mn>2</mml:mn></mml:msqrt><mml:mo>/</mml:mo><mml:msub><mml:mi>r</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math></inline-formula> are strongly suppressed by sub-barrier tunneling. Gravitational wave perturbations (<inline-formula><mml:math><mml:mo>ℓ</mml:mo><mml:mo>≥</mml:mo><mml:mn>2</mml:mn></mml:math></inline-formula>) see a qualitatively similar barrier and are likewise strongly suppressed below their respective barrier-top frequencies. By contrast, the static gravitational monopole (<inline-formula><mml:math><mml:mo>ℓ</mml:mo><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:math></inline-formula>), governed by the linearized Einstein equations on the same background, satisfies the source-free conservation law <inline-formula><mml:math><mml:mo>(</mml:mo><mml:msup><mml:mi>a</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:msup><mml:mi>Φ</mml:mi><mml:mo>'</mml:mo></mml:msup><mml:msup><mml:mo>)</mml:mo><mml:mo>'</mml:mo></mml:msup><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:math></inline-formula> with no potential barrier, yielding the exact solution <inline-formula><mml:math><mml:mi>Φ</mml:mi><mml:mo>∝</mml:mo><mml:mi>arctan</mml:mi><mml:mo>(</mml:mo><mml:mi>σ</mml:mi><mml:mo>/</mml:mo><mml:msub><mml:mi>r</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:mo>)</mml:mo></mml:math></inline-formula>. We extend these results to a one-parameter family of throat geometries with varying profile shapes, and to a reflected-Schwarzschild (Damour-Solodukhin-type) wormhole, demonstrating that the qualitative asymmetry—strong sub-barrier suppression for all propagating radiation (<inline-formula><mml:math><mml:mo>ℓ</mml:mo><mml:mo>≥</mml:mo><mml:mn>1</mml:mn></mml:math></inline-formula>) versus polynomial attenuation for the static monopole (<inline-formula><mml:math><mml:mo>ℓ</mml:mo><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:math></inline-formula>)—is universal for static, spherically symmetric throats. Numerov integration, WKB estimates, and exact analytical solutions are compared throughout. The results establish a structural constraint-wave asymmetry arising from the multipole decomposition of the field equations, independent of the matter content sourcing the geometry, on a fixed background.