Ya. B. Zeldovich All-Moscow Seminar of Astrophysicists

На северо-востоке Большого Магелланова Облака рядом друг с другом находятся две гигантские ( простирающиеся на сотни парсек) уникально правильные дуги молодых звезд, одна охватывающая четверть окружности («Квадрант) и вторая, меньшая - ее шестую часть («Секстант»). Их природа обсуждается уже почти полвека, выдвигались разнообразные гипотезы, но общепринятого решения нет.

It was proposed in 2003 that origin of these arcs was due to the bow shock from the jet, which is intermittently fired by the Milky Way nucleus – and during the last episode of its activity the jet was pointed to the LMC. Quite recently evidence for such a jet has really appeared. We now suppose it was once energetic enough to trigger star formation in the LMC, and if the jet opening angle was about 2°, it could push out HI gas from the region of about 2 kpc in size, forming a HI cavity LMC4, - but also squeezed two dense clouds, which occurred in the same area, causing the formation of stars along their surfaces facing the core of the MW. In result, spherical segments of the stellar shells might arise, visible now as the arcs of Quadrant and Sextant, the apices of which point to the center of the MW. This orientation of both arcs can be the key to unlocking their origin. Here we give data which confirm the above hypothesis