We report on X-ray polarization measurements of the extragalactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud, using a similar to 850 ks Imaging X-ray Polarimetry Explorer (IXPE) exposure. The PWN is unresolved by IXPE. No statistically significant polarization is detected for the image-averaged data, giving a 99% confidence polarization upper limit (MDP99) of 5.3% in the 2-8 keV energy range. However, a phase-resolved analysis detects polarization for both the nebula and pulsar in the 4-6 keV energy range. For the PWN defined as the off-pulse phases, the polarization degree (PD) of (24.5 +/- 5.3)% and polarization angle (PA) of (78.1 +/- 6.2)degrees is detected at 4.6 sigma significance level, consistent with the PA observed in the optical band. In a single on-pulse window, a hint of polarization is measured at 3.8 sigma with PD of (50.0 +/- 13.1)% and PA of (6.2 +/- 7.4)degrees. A "simultaneous" PSR/PWN analysis finds two bins at the edges of the pulse exceeding 3 sigma PD significance, with PD of (68 +/- 20)% and (62 +/- 20)%; intervening bins at 2-3 sigma significance have lower PD, hinting at additional polarization structure.

Xie, F., Wong, J., La Monaca, F., Romani, R.W., Heyl, J., Kaaret, P., et al. (2024). First Detection of Polarization in X-Rays for PSR B0540-69 and Its Nebula. THE ASTROPHYSICAL JOURNAL, 962(1) [10.3847/1538-4357/ad17ba].

First Detection of Polarization in X-Rays for PSR B0540-69 and Its Nebula

Bianchi, Stefano;De Rosa, Alessandra;Marinucci, Andrea;Matt, Giorgio;Petrucci, Pierre-Olivier;Taverna, Roberto;
2024-01-01

Abstract

We report on X-ray polarization measurements of the extragalactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud, using a similar to 850 ks Imaging X-ray Polarimetry Explorer (IXPE) exposure. The PWN is unresolved by IXPE. No statistically significant polarization is detected for the image-averaged data, giving a 99% confidence polarization upper limit (MDP99) of 5.3% in the 2-8 keV energy range. However, a phase-resolved analysis detects polarization for both the nebula and pulsar in the 4-6 keV energy range. For the PWN defined as the off-pulse phases, the polarization degree (PD) of (24.5 +/- 5.3)% and polarization angle (PA) of (78.1 +/- 6.2)degrees is detected at 4.6 sigma significance level, consistent with the PA observed in the optical band. In a single on-pulse window, a hint of polarization is measured at 3.8 sigma with PD of (50.0 +/- 13.1)% and PA of (6.2 +/- 7.4)degrees. A "simultaneous" PSR/PWN analysis finds two bins at the edges of the pulse exceeding 3 sigma PD significance, with PD of (68 +/- 20)% and (62 +/- 20)%; intervening bins at 2-3 sigma significance have lower PD, hinting at additional polarization structure.
2024
Xie, F., Wong, J., La Monaca, F., Romani, R.W., Heyl, J., Kaaret, P., et al. (2024). First Detection of Polarization in X-Rays for PSR B0540-69 and Its Nebula. THE ASTROPHYSICAL JOURNAL, 962(1) [10.3847/1538-4357/ad17ba].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/466352
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