X-Ray Polarization Detection of the Pulsar Wind Nebula in G21.5-0.9 with IXPE
: Di Lalla, Niccolò; Omodei, Nicola; Bucciantini, Niccolò; Dinsmore, Jack T.; Cibrario, Nicolò; Silvestri, Stefano; Wong, Josephine; Slane, Patrick; Mizuno, Tsunefumi; Negro, Michela; Romani, Roger W.; Ferrazzoli, Riccardo; Ng, C.-Y.; Michailidis, Miltiadis; Yang, Yi-Jung; Xie, Fei; Weisskopf, Martin C.; Kaaret, Philip; Agudo, Iván; Antonelli, Lucio A.; Bachetti, Matteo; Baldini, Luca; Baumgartner, Wayne H.; Bellazzini, Ronaldo; Bianchi, Stefano; Bongiorno, Stephen D.; Bonino, Raffaella; Brez, Alessandro; Capitanio, Fiamma; Castellano, Simone; Cavazzuti, Elisabetta; Chen, Chien-Ting; Ciprini, Stefano; Costa, Enrico; De Rosa, Alessandra; Del Monte, Ettore; Di Gesu, Laura; Di Marco, Alessandro; Donnarumma, Immacolata; Doroshenko, Victor; Dovčiak, Michal; Ehlert, Steven R.; Enoto, Teruaki; Evangelista, Yuri; Fabiani, Sergio; Garcia, Javier A.; Gunji, Shuichi; Heyl, Jeremy; Iwakiri, Wataru; Jorstad, Svetlana G.; Karas, Vladimir; Kislat, Fabian; Kitaguchi, Takao; Kolodziejczak, Jeffery J.; Krawczynski, Henric; La Monaca, Fabio; Latronico, Luca; Liodakis, Ioannis; Maldera, Simone; Manfreda, Alberto; Marin, Frédéric; Marinucci, Andrea; Marscher, Alan P.; Marshall, Herman L.; Massaro, Francesco; Matt, Giorgio; Mitsuishi, Ikuyuki; Muleri, Fabio; O’Dell, Stephen L.; Oppedisano, Chiara; Papitto, Alessandro; Pavlov, George G.; Peirson, Abel Lawrence; Perri, Matteo; Pesce-Rollins, Melissa; Petrucci, Pierre-Olivier; Pilia, Maura; Possenti, Andrea; Poutanen, Juri; Puccetti, Simonetta; Ramsey, Brian D.; Rankin, John; Ratheesh, Ajay; Roberts, Oliver J.; Sgró, Carmelo; Soffitta, Paolo; Spandre, Gloria; Swartz, Douglas A.; Tamagawa, Toru; Tavecchio, Fabrizio; Taverna, Roberto; Tawara, Yuzuru; Tennant, Allyn F.; Thomas, Nicholas E.; Tombesi, Francesco; Trois, Alessio; Tsygankov, Sergey; Turolla, Roberto; Vink, Jacco; Wu, Kinwah; Zane, Silvia
Publisher: Institute of Physics
: 2025
Astrophysical Journal
: 67
: 991
: 1
: 0004-637X
: 1538-4357
DOI: https://doi.org/10.3847/1538-4357/adf6b5
: https://doi.org/10.3847/1538-4357/adf6b5
: https://research.utu.fi/converis/portal/detail/Publication/505010686
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.
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R.F., E.Co., A.D.M., S.F., F.L.M., F.Mu., and P.So. are partially supported by MAECI with grant CN24GR08 “GRBAXP: Guangxi Rome Bilateral Agreement for X-ray Polarimetry in Astrophysics.” C.-Y.N. is supported by a GRF grant of the Hong Kong Government under HKU 17304524. N.B. was supported by the INAF MiniGrant “PWNnumpol—Numerical Studies of Pulsar Wind Nebulae in The Light of IXPE.” F.X. is supported by National Natural Science Foundation of China (grant Nos. 12373041 and 12422306), and Bagui Scholars Program (XF). I.L. was funded by the European Union ERC-2022-STG – BOOTES – 101076343.
