Science News内容：

题目：Discovery of a millisecond pulsar associated with Terzan 6

摘要：Observations show that globular clusters might be among the best places to find millisecond pulsars. However, the globular cluster Terzan 6 seems to be an exception without any pulsar discovered, although its high stellar encounter rate suggests that it harbors dozens of them. We report the discovery of the first radio pulsar, PSR J1750-3116A, likely associated with Terzan 6 in a search of C-band (4-8 GHz) data from the Robert C. Byrd Green Bank Telescope with a spin period of 5.33 ms and dispersion measure, DM ≈ 383 pc cm−3. The mean flux density of this pulsar is approximately 3 μJy. The DM agrees well with predictions from the Galactic free electron density model, assuming a distance of 6.7 kpc for Terzan 6. PSR J1750-3116A is likely an isolated millisecond pulsar, potentially formed through dynamical interactions, considering the core-collapsed classification and the exceptionally high stellar encounter rate of Terzan 6. This is the highest radio frequency observation that has led to the discovery of a pulsar in a globular cluster to date. While L-band (1-2 GHz) observations of this cluster are unlikely to yield significant returns due to propagation effects, we predict that further pulsar discoveries in Terzan 6 will be made by existing radio telescopes at higher frequencies.

报告人：马思冲（紫台研究生） 

Journal club内容：

题目：An explanation for the formation of the peculiar periphery of the Cygnus Loop supernova remnant

摘要：Analyzing images of the Cygnus Loop, a core-collapse supernova (CCSN) remnant, in different emission bands, we identify a morphology composed of three symmetry axes that we attribute to shaping by three pairs of jets. The main jet axis has an elongated S shape, appearing as a faint narrow zone in visible and UV. We term it the S-shaped hose. The two other lines connect a protrusion (an ear or a bulge) with a hole on the opposite side of the center (a nozzle or a cavity), structures that we identify in the X-ray, UV, visible, IR, and/or radio images. There is a well-known blowout at the southern end of the S-shaped hose, and we identify a possible opposite blowout at the northern end of the S-shaped hose. The morphology of the Cygnus Loop is according to the expectation of the jittering jets explosion mechanism of CCSNe, where several to few tens of pairs of jets with stochastically varying directions explode the star. The three pairs of jets that shaped the structure of the Cygnus Loop are the last energetic pairs of this series of jets.

报告人：沈君宇（紫台研究生）

时间：2024年11月5日星期二12:15

地点：紫台3-302

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