We have numerically simulated the evolution of supernova remnant VRO 42.05.01(G166.0+43) in order to understand its morphology m radio and X-ray observations as well as the dynamical interaction of the supernova remnant with the surrounding interstellar medium. The Radio and ROSAT observations suggest that the unusual morphology of VRO 42.05.01 is caused by a supernova blast wave breaking out of the cloud boundary where the supernova event occurred, and expanding into another cloud across a much less dense and presumably hot cavity. Our numerical results are consistent with the interactions of a passing supernova blast wave with the clouds across the cavity. We discuss the implications of our results on the dynamics of VRO 42.05.01 such as the reverse shocks, the rejuvenation of the hot cavity, and the reflected shocks formed by the reverse shock collisions. We have theoretically mapped the radio continuum(1.4 GHz) and X-ray(0.1~2 keV) morphology which are consistent with the observational ones.
We introduce the National Science Curriculum issued by the Education Ministry in Korea. Astronomy should be given and taught as compulsory courses in Nature of elementary school, Science of middle school, General Science of high school, and as elective courses in Earth Science I, II. Astronomy concepts have been designed in sprial pattern. College levels of astronomy have been given as majoring in astronomy course, cultivating one for earth science pre-teacher students and cultural subjects for non-major students
We describe the implementation of a multi-dimensional numerical code to solve the equations for idea! magnetohydrodynamics (MHD) in cylindrical geometry. It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a second-order-accurate extension of the Roe-type upwind scheme. Multiple spatial dimensions are treated through a Strang-type operator splitting. Curvature and source terms are included in a way to insure the formal accuracy of the code to be second order. The constraint of a divergence-free magnetic field is enforced exactly by adding a correction, which involves solving a Poisson equation. The Fourier Analysis and Cyclic Reduction (FACR) method is employed to solve it. Results from a set of tests show that the code handles flows in cylindrical geometry successfully and resolves strong shocks within two to four computational cells. The advantages and limitations of the code are discussed.
NGC 7023 have been observed in ^(12)CO and ^(13)CO (J=1→ 0) molecular line emissions. It possesses bipolar molecular outflows which are moving out both eastward and westward in Right Ascension with a velocity range of ±9 ㎞s^(-1) with an inclination of ∼80° The mass loss rate is ∼10^(-5)M◎_(yr)^(-1) with an assumed stellar wind velocity of ∼100㎞s^(-1); the dynamical age of this outflow is ∼5.5×10⁴ years. The bipolar molecular outflows would be collimated by the molecular disk surrounding HD 200775, which is explained by either the velocity gradient of ∼0.25 ㎞s^(-1) are min^(-1) in the position-velocity map of ^(12)CO along the Declination or the peak temperature maps of both ^(12)CO and ^(12)CO. The outflows also yield high density regions at their ends, producing the region of the low mass star formation.