SIMBAD references

We carried out a wide-field [S II]-emission imaging of the Monoceros OB1 molecular cloud (NGC 2264) to investigate the star formation and outflow activity of the region. Our narrowband [S II] imaging covers an area of sky of ∼2 deg², including the entire Mon OB1 cloud. In the northern part of the cloud two new Herbig-Haro (HH) objects, HH 572 and HH 575, are discovered. All four of the previously known HH objects, HH 124, 125, 225, and 226, are also detected in our imaging. Low-dispersion spectroscopic observations of HH 572A, 575B, and 575C1 further confirmed the HH-object nature of these objects. Molecular hydrogen v=1-0 S(1) narrowband imaging revealed a bright H₂emission knot in each of the HH 572 and HH 575 regions. By comparing the results of our optical [S II] emission survey with those of the CO molecular outflow survey, it is found that the occurrence frequency of HH objects is similar to that of CO outflows in the Mon OB1 cloud. However, HH objects and CO outflows display different spatial distributions.