《Chandra N132D大型計畫觀測- 前激波的擴展》研討會

Seminar:- Chandra Large Project Observation of N132D- Expansion of the Forward Shock

The speaker presents first results from the Chandra Large Project observation of the Large Magellanic Cloud(LMC) supernova remnant N132D. N132D was observed in 28 separate observations during 2019 and 2020 totaling more than 878 ks. The speaker and his team compare the new data to archival data acquired in 2006 to measure the expansion of the forward shock in the bright southern rim to be 0.”112±0.”024 over the ∼14.15 yr baseline which corresponds to a velocity of 1877±402 km s⁻¹. They measure a shock velocity of 3503±255 km s⁻¹ for a feature in an apparent blowout region in the north-east and use this value to estimate the deceleration of the shock wave in the molecular cloud interaction region. After accounting for the PSF azimuthal difference, the corrected expansion velocity of the southern ring is 1709±386 km s⁻¹, and the velocity of north-east feature is 3738±235 km s⁻¹. The average temperature inferred from X-ray spectral fits to regions in the southern rim is 0.99 keV. It is consistent with the electron temperature implied by the shock velocity they measured, assuming full non-equilibration between electrons and ions. They fitted 1-D evolutionary models for the SNR shock in the Southern rim and Northeast region, using the measured forward shock radius and velocity for propagation into a constant density and power-law profile circumstellar medium. We found good agreement with the age derived from optical measurements of approximately 2500 years, for explosion energies of 1.5 − 2.5 × 10⁵¹ ergs and ejecta masses of 2 − 5M⊙ in a constant density medium. He also discusses the model of a shock propagating in a cavity and then interacting with a dense shell of material.

時間:2024.03.14(三) 14:00
地點:香港大學 莊月明物理樓* 522室
講者:Dr. LONG Xi (Smithsonian Astrophysical Observatory, US)



*Chong Yuet Ming Physics Building



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