Subjects: Astronomy submitted time 2024-03-26 Cooperative journals: 《天文学进展》
Abstract： High energy particles near the particle acceleration region in young supernova remnants and pulsar wind nebulae can emit X-ray synchrotron radiation. The polarization measurement of this radiation can reveal the properties of the magnetic field in the particle acceleration region, and further study the mechanism of particle acceleration. As the first X-ray polarization imaging satellite, the Imaging X-ray Polarization Detector (IXPE) was launched in late 2021 and revealed the X-ray polarization images of several young supernova remnants and pulsar wind nebulae. Observations show that Cas A and Tycho’s supernova remnant have low polarization degrees with average values of about 2.5% and 9%, respec#2;tively, while the Crab Nebula and Vela pulsar wind nebula have higher polarization degrees, averaging about 20% and 45%, respectively. The results indicate that the magnetic field of the pulsar wind nebulae is relatively ordered, while the magnetic field of the particle accel#2;eration region in the two young supernova remnants is highly turbulent and the magnetic field structure near the shock wave shows a radial distribution. In the future, with more extensive observations of IXPE and more telescopes such as the enhanced X-ray Timing and Polarimetry (eXTP) mission planned by China in use, the magnetic field configuration and particle acceleration models of the above two types of objects will be further constrained.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： High energy particles near the particle acceleration region in young supernova remnants and pulsar wind nebulae can emit X-ray synchrotron radiation. The polarization measurement of this radiation can reveal the properties of the magnetic field in the particle acceleration region, and further study the mechanism of particle acceleration. As the first X-ray polarization imaging satellite, the Imaging X-ray Polarization Detector (IXPE) was launched in late 2021 and revealed the X-ray polarization images of several young supernova remnants and pulsar wind nebulae. Observations show that Cas A and Tycho’s supernova remnant have low polarization degrees with average values of about 2.5% and 9%, respec#2;tively, while the Crab Nebula and Vela pulsar wind nebula have higher polarization degrees, averaging about 20% and 45%, respectively. The results indicate that the magnetic field of the pulsar wind nebulae is relatively ordered, while the magnetic field of the particle accel#2;eration region in the two young supernova remnants is highly turbulent and the magnetic field structure near the shock wave shows a radial distribution. In the future, with more extensive observations of IXPE and more telescopes such as the enhanced X-ray Timing and Polarimetry (eXTP) mission planned by China in use, the magnetic field configuration and particle acceleration models of the above two types of objects will be further constrained.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： : Superbubbles are large shell-like interstellar medium structures formed by stel#2;lar winds from massive stars and supernovae. With obvious emission signatures in multiple wavelengths, superbubbles are important sites for studying the radiation mechanisms. 30 Doradus C (30 Dor C in short) is located southwest of 30 Dor in the Large Magellanic Cloud. Its location is basically consistent with OB association LH 90, suggesting that this super#2;bubble may have been created by it. Since 30 Dor C was detected in X-ray band by Einstein satellite in 1981, its X-ray emission has been observed and studied for many years. 30 Dor C is the only superbubble dominated by non-thermal emission in the Large Magellanic Cloud and it’s also the largest non-thermal X-ray emission source in the Local Group. The non#2;thermal emission covers the entire region of the superbubble and is most significant at the shell. Such bright non-thermal emission may due to particle acceleration in the superbubble, and to find out the evidence, the magnetic field conditions in the superbubble and radiation in other bands have also been studied. Compared to non-thermal emission, thermal emission in 30 Dor C is relatively faint. Most of the thermal emission is detected in the eastern region of 30 Dor C, and there are also a supernova remnant found outside the superbubble at the southeast of the shell. In recent years, with the advancement of radio observation, the s#2;tudy of molecular clouds of 30 Dor C has also increased. This paper reviews and summarizes the research of 30 Dor C up to now. The basic situation of thermal emission, non-thermal emission and other bands are discussed first. Meanwhile, a summary is provided on the point sources discovered inside the superbubble. The evidence of particle acceleration in#2;side 30 Dor C is discussed according to the radiation situation, as well as current particle acceleration models and the formation reasons of 30 Dor C.
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