Document Type
Article
Publication Date
9-20-2025
Abstract
We present the X-ray polarization observation of G21.5−0.9, a young Galactic supernova remnant (SNR), conducted with the Imaging X-ray Polarimetry Explorer (IXPE) in 2023 October, with a total livetime of approximately 837 ks. Using different analysis methods, such as a space-integrated study of the entire region of the pulsar wind nebula (PWN) and a space-resolved polarization map, we detect significant polarization from the PWN at the center of the SNR, with an average polarization degree of ∼10% oriented at ∼33° (north through east). No significant energy-dependent variation in polarization is observed across the IXPE band (2-8 keV). The polarization map, corrected for the effect of polarization leakage, reveals a consistent pattern in both degree and angle, with little change across the nebula. Our findings indicate the presence of a highly polarized central torus, suggesting low levels of turbulence at particle acceleration sites. Unlike Vela, but similar to the Crab Nebula, we observe substantial differences between radio and X-ray polarization maps. This suggests a clear separation in energy of the emitting particle populations and hints at an important, yet poorly understood, role of instabilities in the turbulence dynamics of PWNe.
Publication Source (Journal or Book title)
Astrophysical Journal
Recommended Citation
Di Lalla, N., Omodei, N., Bucciantini, N., Dinsmore, J., Cibrario, N., Silvestri, S., Wong, J., Slane, P., Mizuno, T., Negro, M., Romani, R., Ferrazzoli, R., Ng, C., Michailidis, M., Yang, Y., Xie, F., Weisskopf, M., Kaaret, P., Agudo, I., Antonelli, L., Bachetti, M., Baldini, L., Baumgartner, W., Bellazzini, R., Bianchi, S., Bongiorno, S., Bonino, R., Brez, A., Capitanio, F., Castellano, S., Cavazzuti, E., Chen, C., & Ciprini, S. (2025). X-Ray Polarization Detection of the Pulsar Wind Nebula in G21.5-0.9 with IXPE. Astrophysical Journal, 991 (1) https://doi.org/10.3847/1538-4357/adf6b5