The Magnetic Field in the Colliding Filaments G202.3+2.5

We observe the magnetic field morphology towards a nearby star-forming filamentary cloud, G202.3+2.5, by the JCMT/POL-2 850 mu muthermal dust polarization observation with an angular resolution of 14.4" (similar to 0.053 pc). The average magnetic field orientation is found to be perpendicular to the filaments while showing different behaviors in the four subregions, suggesting various effects from filaments' collision in these subregions. With the kinematics obtained by N2H+ observation by IRAM, we estimate the plane-of-sky (POS) magnetic field strength by two methods, the classical Davis-Chandrasekhar-Fermi (DCF) method and the angular dispersion function (ADF) method, B-pos,B-dcf and B-pos,B-adf are similar to 90 and similar to 53 mu G. We study the relative importance between the gravity (G), magnetic field (B) and turbulence (T) in the four subregions, find G > T > B, G >= T > B, G similar to T > B and T > G > B in the north tail, west trunk, south root and east wing, respectively. In addition, we investigate the projection effect on the DCF and ADF methods based on a similar simulation case and find the 3D magnetic field strength may be underestimated by a factor of similar to 3 if applying the widely-used statistical B-pos-to-B-3D factor when using DCF or ADF method, which may further underestimate/overestimate related parameters.