arXiv subjects

Wen-Long Xu

Publications and source records attributed to Wen-Long Xu.

5 recordsLinked to original sources

arXiv2026

Infrared Echoes of Precessing Tidal Disruption Events

A tidal disruption event (TDE) occurs when a star is torn apart by a supermassive black hole. The resulting UV/optical flare irradiates parsec-scale dust, producing delayed mid-infrared echoes that persist for years. These echoes provide unique calorimetric probes of the total radiated energy and dust geometry. Existing models usually assume static axisymmetric illumination patterns. However, the TDE accretion disk is likely misaligned and undergoes relativistic precession. In this work, we present a theoretical framework for infrared dust echoes from a precessing TDE disk. The precession will lead to highly variable infrared light curves, which can be revealed by high-cadence observations. The overall profile of the infrared light curves shows double-peaked to single-peaked pattern transitions as a result of the changes in the viewing angle or precession angle. The results indicate that infrared echoes are dynamic tracers of the evolving lighting patterns of the central engine.

astro-ph.HE↗

arXiv2026

Estimating the Lensing Probability for Binary Black Hole Mergers in AGN disk by Using Mismatch Threshold

Stellar-mass binary black holes (BBH) may form, evolve, and merge within the dense environments of active galactic nuclei (AGN) disks, thereby contributing to the BBH population detected by gravitational wave (GW) observatories. Mergers occurring in AGN disks may be gravitationally lensed by the supermassive black hole at the AGN centre. The probability of such lensing events has been approximately estimated by using the Einstein criterion in previous work. However, a more reasonable approach to calculating the lensing probability should be based on whether the detector can distinguish the lensed GW waveform from the unlensed one. In this work, we calculate the lensing probability of LIGO sources embedded in AGN disk by relating threshold mismatch to the signal-to-noise ratio of the observed events. For the sensitivity of LIGO-Virgo-KAGRA O3 observation runs, our results indicate that the lensing probability is several times higher than previous estimates. If AGNs are indeed the primary formation channel for BBHs, we could quantify the probability of detecting the lensed GW events in such a scenario. The non-detections, on the other hand, will place stricter constraints on the fraction of AGN disk BBHs and even the birthplaces of BBH mergers.

astro-ph.HE↗

arXiv2026

A possible origin of the overlapping light curve of eRO-QPE1

Quasi-Periodic Eruptions (QPEs) are recurrent X-ray eruptions discovered so far in the nuclei of low-mass galaxies. However, despite considerable observational progress, the origin of QPEs remains unclear. A variety of models have been proposed to explain their nature, but a definitive understanding has yet to be reached. Recently, chaotic mixtures of multiple overlapping eruptions with varying amplitudes have been observed in eRO-QPE1 obs1-features not reported in any other known QPE sources. This complex behavior presents a challenge to the existing QPE models. In this paper, we propose that the overlapping features may be the result of gravitational lensing. We analyze the light curve of eRO-QPE1 and compare its features to predictions from gravitational lensing scenarios. We discuss the implications for the trigger mechanism of QPEs in general. We show that the unique overlapping features observed in eRO-QPE1 may be naturally reproduced by gravitational lensing effects, without invoking a different physical origin from other known QPE sources.

astro-ph.HE↗

arXiv2026

Neutrino Emission from Gamma-ray Burst Jet Propagating inside the Cavity within Active Galactic Nucleus Accretion Disks

Short gamma-ray bursts (sGRBs) from the merger of binary compact objects (BCOs) could occur in the accretion disks of the active galactic nucleus (AGN). Before merging, the BCO will inevitably form a low-density cavity. The sGRB jet will interact with the AGN disk photons during its propagation through the cavity, leading to unique electromagnetic and neutrino signatures. In this work, we investigate the influence of the AGN disk photon field on neutrino emission within the internal dissipation regions of a two-component sGRB jet (a narrow core and a wide wing). We find that, due to the strong AGN disk photon field, the neutrino flux at high-energy part (e.g., PeV to EeV) will be suppressed, while the relatively lower-energy part (e.g., TeV to PeV) will be enhanced. Such a conclusion can enhance the constraints on GRB parameters (e.g., baryonic loading factor and bulk Lorentz factor) based on the future detection or non-detection of high-energy neutrinos from GRBs. Besides, the two-component jet can display two-bump structure at higher and lower energy in the neutrino spectrum. Therefore, the joint observations of electromagnetic and neutrinos emission can help us identify the sGRB jet and its structure in the AGN disk.

astro-ph.HE↗

arXiv2025

Lense-Thirring Precession Modulates Repeated Lensing of Continues Gravitational Wave Source from AGN Disks

Gravitational lensing of gravitational waves (GWs) offers a novel observational channel that complements traditional electromagnetic approaches and provides unique insights into the astrophysical environments of GW sources. In this work, we investigate the repeated lensing of continuous gravitational wave (CW) sources in active galactic nucleus (AGN) disks by central supermassive black holes (SMBHs), focusing on the imprint of SMBH spin via the Lense-Thirring (LT) effect. Although typically weak and challenging to observe, the spin-induced precession of source orbits can accumulate over time, thereby modulating the lensing geometry. Such modulations influence the magnification, duration, and waveform structure of each repeated lensing event, and enhance the overall probability of lensing occurrences. Using matched filtering, we demonstrate that spin-dependent signatures may be detectable, suggesting that lensed CW signals could serve as an indirect probe of SMBH spin in AGNs.

astro-ph.HE↗