Speaker
Description
We report on results of CO observations in the northwestern shell of the supernova remnant (SNR) RX J1713.7$-$3946 using the Atacama Large Millimeter/submillimeter Array (ALMA). We recently found dozens of molecular cloudlets with typical radii of $\sim$0.03-0.05 pc and densities of $\sim$$10^4$ cm$^{-3}$, which have survived shock passage due to their high density. These cloudlets are located not only along synchrotron X-ray filaments, but also in the vicinity of X-ray hotspots with month- or year-scale time variations. We argue that X-ray hotspots and filaments were generated by shock-cloudlet interactions through magnetic-field amplification up to mG. The gas density contrast of $\sim$$10^5$, the coexistence of molecular cloudlets and low-density diffuse medium of $\sim$0.1 cm$^{-3}$, is consistent with such a magnetic field amplification and a wind-bubble scenario. The small-scale cloud structures also affect hadronic gamma-ray spectra considering the magnetic field amplification on surface and inside clouds.
