arXiv subjects

Changwen Zeng

Publications and source records attributed to Changwen Zeng.

3 recordsLinked to original sources

arXiv2026

Prospect for Detection of Strongly Lensed Multi-messenger Signals of Binary Neutron Star Mergers

The gravitational lensing of multi-messenger signals from binary neutron star mergers (BNSs), including gravitational waves (GWs), short Gamma-Ray bursts (sGRBs), kilonovae, and afterglows, can serve as a unique probe to constrain the mass of the graviton and cosmological parameters. In this paper, we estimate the detection rates of lensed electromagnetic counterparts associated with lensed BNS GW events detected by Cosmic Explorer and Einstein Telescope. For kilonovae and afterglows, we further consider a complementary pointed follow-up strategy targeting pre-identified galaxy-scale lens candidates within the GW localization region. By utilizing both numerical and observational constraints on BNS mergers, we find that: (1) Future $\gamma$-ray telescopes, even with a sensitivity more than ten times better than that of Fermi-GBM, may only detect lensed sGRB prompt emission at a rate $\sim 0.1$ yr$^{-1}$, corresponding to $\sim 2\times 10^{-3}$ of detectable lensed BNS GW events. (2) For the known-lens pointed strategy, the identifiable lensed-host fraction is approximately $0.15-0.30$ for the fiducial deep lens-catalog case considered, suggesting a possible gain in per-lens sensitivity for faint kilonovae and afterglows. (3) An RST-like near-infrared facility could detect lensed kilonovae at rates of approximately $\sim 0.45^{+0.81}_{-0.34}$, $0.55^{+0.98}_{-0.41}$, and $0.078^{+0.139}_{-0.059}$ yr$^{-1}$ in the F106, F158, and F213 bands, respectively. (4) Lensed afterglows remain difficult to detect in the optical and radio bands, while ATHENA-like X-ray observations may detect $0.5-5$ events over ten years.

astro-ph.HE↗

arXiv2026

Revisiting Approaches to Stellar White-Light Flare Energy Based on Spatiotemporally Resolved Solar Observations

Accurately estimating the bolometric energy of solar and stellar white-light flares (WLFs) is crucial for understanding their physical nature and impact on surrounding planets. However, the lack of spatial resolution in stellar observations forced pioneering stellar WLF studies to adopt simplified energy estimation methods, typically assuming either a constant flare temperature or a fixed radiating area. To assess the physical plausibility of these assumptions, we utilize high-spatiotemporal-resolution solar observations to analyze the true evolution of source region's radiating area and temperature of 70 solar WLFs. It is revealed that both area and temperature of most solar WLFs undergo significant temporal evolution, and the flare area strongly correlates with the flare's peak optical continuum flux. Therefore, we propose a new energy estimation method that permits both flare area and temperature to evolve. Compared with existing methods, our dynamic approach yields systematically lower flare energies, which then prompts us to revisit classical macroscopic scaling laws related to the flare energy. It is further revealed that different energy estimation approaches can systematically alter these scaling relations, calling for a re-examination of these established statistical results and their targeted testing or revision in future work.

astro-ph.SR↗

arXiv2025

Constraining Common Envelope Evolution in Binary Neutron Star Formation with Combined Galactic and Gravitational-Wave Observations

Binary neutron stars (BNSs) are among the most interesting sources for multimessenger studies. A number of recently discovered BNSs in the Milky Way by radio telescopes have added new information to the parameter distribution of the Galactic BNSs. The scarcity of BNS mergers during the O4 run of the LIGO-Virgo-Kagra (LVK) suggests a BNS local merger rate six times lower than the previous constraint obtained by O1-O3 runs. With these new multimessenger observations, in this letter, we adopt the compact binary population synthesis model and Bayesian analysis to constrain the formation and evolution of BNSs, especially the common envelope (CE) evolution. We find that it is required: (1) a fraction ($f_{\rm HG}\sim0.8$) but not all of the Hertzsprung gap donors merged with their companions in the CE stage, in order to simultaneously explain the low BNS merger rate density and the existence of the short-orbital-period ($\lesssim 1$ day) Galactic BNSs, different from either all ($f_{\rm HG}=1$) or none ($f_{\rm HG}=0$) adopted in previous studies; (2) a large CE ejection efficiency $\alpha$ ($\sim 5$), in order to explain the existence of the long-orbital-period ($\gtrsim 10$ day) Galactic BNSs.

astro-ph.HE↗