Evidence of an Energetic Magnetar Powering 1LHAASO J0500$+$4454
J. A. J. Alford, J. D. Gelfand, M. Abdelmaguid, P. Slane
TL;DR
Addresses the origin of the unidentified TeV source 1LHAASO J0500+4454 by evaluating hadronic and leptonic scenarios, including a potential magnetar-powered PWN. The analysis uses upper limits on CO and X-ray emission to constrain molecular-cloud and SNR origins and applies spectral-energy-distribution modeling to different energy budgets. The results disfavor both molecular-cloud hadronic and SNR scenarios, and a leptonic PWN powered by inverse Compton scattering remains viable, requiring a current nebular particle energy of $4 \times 10^{48}$ erg. If the magnetar SGR 0501+4516 supplies the energy, a conservative budget implies $P_{0} \lesssim 5$ ms and $\tau_{\rm sd} \lesssim 30$ yr, with implications for magnetar birth properties and the occurrence of magnetar-powered TeV emission.
Abstract
We investigate the origin of unidentified, extended TeV source 1LHAASO J0500$+$4454, considering three possible origins: cosmic rays interacting with a molecular cloud (MC), particles accelerated in a currently undetected supernova remnant (SNR), and an energetic outflow powered by a pulsar. Upper limits on the CO and X-ray emission from the $γ$-ray emitting region disfavor the MC and SNR scenarios, respectively. If a nebula of inverse Compton scattering $e^{\pm}$ powers 1LHAASO J0500$+$4454, then SED modeling indicates that the current particle energy in the nebula is $\sim 4 \times 10^{48}$ erg. If the coincident magnetar SGR 0501$+$4516's rotational energy powered 1LHAASO J0500$+$4454, then a conservative energy budget calculation requires an initial magnetar spin period $P_{0} \lesssim 5$ ms and a spin-down timescale $τ_{\rm sd} \lesssim 30$ yr, which has implications for the origins of magnetars.