Unlocking the radio- γ spectrum of the pulsar wind nebula around PSR J1124–5916 in SNR G292.0+1.8

¹ Université Paris Cité, CNRS, Astroparticule et Cosmologie, 75013 Paris, France
² Instituto de Astronomía y Física del Espacio (IAFE), CONICET-Universidad de Buenos Aires, Intendente Güiraldes 2160 ( C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
³ Observatorio Astronómico Félix Aguilar (OAFA), FCEFyN – Universidad Nacional de San Juan, Benavidez 8175 (O), San Juan, Argentina

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 2 July 2025
Accepted: 4 October 2025

Abstract

We present the first detection of GeV γ-ray emission potentially associated with the pulsar wind nebula (PWN) hosted by the young core-collapse supernova remnant G292.0+1.8, based on a detailed, time-resolved analysis of Fermi-LAT data. By isolating the unpulsed component from the dominant magnetospheric radiation of PSR J1124-5916, we successfully disentangled a candidate nebular emission in the GeV range, characterized its morphology, and extracted its spectrum. This identification places G292.0+1.8 among the few systems in which the pulsar and PWN contributions have been spectrally resolved at high energies, offering new insight into their respective emission mechanisms. We characterized the γ-ray spectrum of the pulsar and modeled the broadband spectral energy distribution (SED) of the PWN using radio, X-ray, and GeV data. The emission is well described by a single electron population with two spectral breaks: one intrinsic to the injection spectrum and another produced by synchrotron cooling in a magnetic field of ∼15μG. Notably, the inferred magnetic field and the low TeV flux of the nebula resemble those of 3C 58, suggesting that similar low-field environments can arise in young PWNe. The high-energy portion of the SED is now tightly constrained by our GeV detection and the existing TeV upper limits. Compared to our model, earlier predictions tend to underpredict the γ-ray flux, whereas others that succeed in reproducing the GeV component often overpredict the TeV emission. This mismatch underscores the challenges in modeling particle acceleration and radiation processes in young PWNe and establishes G292.0+1.8 as a valuable benchmark for testing and refining such models.