Suchergebnisse

Context. Disentangling line-of-sight alignments of young stellar populations is crucial for observational studies of star-forming complexes. This task is particularly problematic in a Cygnus-X subregion where several components, located at different distances, overlap: the Berkeley 87 young massive cluster, the poorly known [DB2001] Cl05 embedded cluster, and the ON2 star-forming complex, which in turn is composed of several H II regions. Aims. We provide a methodology for building an exhaustive census of young objects that can consistently treat large differences in extinction and distance. Methods. OMEGA2000 near-infrared observations of the Berkeley 87/ON2 field were merged with archival data from Gaia, Chandra, Spitzer, and Herschel and with cross-identifications from the literature. To address the incompleteness effects and selection biases that arise from the line-of-sight overlap, we adapted existing methods for extinction estimation and young object classification. We also defined the intrinsic reddening index, Rint, a new tool for separating intrinsically red sources from those whose infrared color excess is caused by extinction. Finally, we introduce a new method for finding young stellar objects based on Rint. Results. We find 571 objects whose classification is related to recent or ongoing star formation. Together with other point sources with individual estimates of distance or extinction, we compile a catalog of 3005 objects to be used for further membership work. A new distance for Berkeley 87, (1673 ± 17) pc, is estimated as a median of 13 spectroscopic members with accurate Gaia EDR3 parallaxes. Conclusions. The flexibility of our approach, especially regarding the Rint definition, allows overcoming photometric biases caused by large variations in extinction and distance in order to obtain homogeneous catalogs of young sources. The multiwavelength census that results from applying our methods to the Berkeley 87/ON2 field will serve as a basis for disentangling the overlapped populations. ; D.dF. acknowledges the UNAM-DGAPA postdoctoral grant, the Generalitat Valenciana APOSTD/220/228 fellowship, and the Spanish Government AYA2015-68012-C2-2-P project. D.dF. and M.G. have received financial support from Spanish Government project ESP2017-86582-C4-1-R. C.R.-Z. acknowledges support from CONACYT project CB2017-2018 A1-S-9754. C.R.-Z. and E.J.B. acknowledge support from Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica, UNAM-DGAPA, grants IN108117 and IN109217, respectively.