may imply that the evolution of young clusters in this part of the complex proceeds in periods that last 3 to 5 Myr, perhaps after a slow dissipation of their dense molecular cloud birthplaces.'
author:
- 'S. Rivera-Gálvez, C. G. Román-Zúñiga, E. Jiménez-Bailón, J. E. Ybarra, J. F. Alves and Elizabeth A. Lada'
title: 'The Young Stellar Population of the Cygnus-X DR15 Region'
---

=1

Introduction \[intro\]
======================

The star forming complex of Cygnus-X region is one of the most prominent features in our Galaxy. Originally detected as an extended region with a thermal spectrum, @Piddington:1952aa named the region Cygnus-X, in order to distinguish it from the other nearby known radio source, Cygnus-A. Cygnus-X is composed of several OB associations, dozens of embedded stellar clusters, hundreds of HII regions and over 40 known massive protostars [see @Reipurth:2008aa for an extensive review]. The young star population in Cygnus-X is currently interacting with one of the most massive molecular cloud complexes in the Galaxy, with a total mass of $3\times 10^6\ \mathrm{M}_\odot$ [@Schneider:2006aa], as well as the X-ray emitting Cygnus Superbubble. It has been proposed that Cygnus-X could be the precursor of a globular cluster [@Knodlseder:2000aa].

To study the interaction between recently 