出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Cygnus X is one of the closest giant molecular cloud complexes and therefore an extensively studied region of ongoing high mass star formation. However, the distance to this region has been a long-standing issue, since sources at galactic longitude of 80◦ could be in the Local Arm nearby (1–2 kpc), in the Perseus Arm at 5 kpc, or even in the outer arm ( 10 kpc). We use combined observations of the EVN plus two Japanese stations to measure very accurate parallaxes of methanol masers in five star-forming regions in Cygnus X to understand if they belong to one large star-forming complex or if they are separate entities located at different distances. Here we report our preliminary result for W75N based on six epochs of VLBI observations: we find that W75N is at a distance of 1.32+0.11 −0.09 kpc, which is significantly closer than the reported values in the literature (1.5–2 kpc).
