The North American and Pelican Nebulae II. MIPS Observations and Analysis

TL;DR

This study uses Spitzer MIPS and IRAC data, combined with archival observations, to identify over 2000 young stellar objects in the North American and Pelican Nebulae, vastly expanding the known YSO population and revealing detailed cluster structures.

Contribution

It provides a comprehensive catalog of YSOs in the nebulae region using multi-wavelength Spitzer data, significantly increasing the known YSO count and identifying new cluster substructures.

Findings

Identified 2076 YSO candidates, greatly surpassing previous counts.

Revealed three main clusters with distinct properties and high extinction.

Expanded the known extent of the Gulf of Mexico cluster by 10-100 times.

Abstract

We present observations of ~7 square degrees of the North American and Pelican Nebulae region at 24, 70, and 160 microns with the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS). We incorporate the MIPS observations with earlier Spitzer Infrared Array Camera (IRAC) observations, as well as archival near-infrared (IR) and optical data. We use the MIPS data to identify 1286 young stellar object (YSO) candidates. IRAC data alone can identify 806 more YSO candidates, for a total of 2076 YSO candidates. Prior to the Spitzer observations, there were only ~200 YSOs known in this region. Three subregions within the complex are highlighted as clusters: the Gulf of Mexico, the Pelican, and the Pelican's Hat. The Gulf of Mexico cluster is subject to the highest extinction (Av at least ~30) and has the widest range of infrared colors of the three clusters, including the largest excesses and by far the most point-source detections at 70 microns. Just 3% of the cluster members were previously identified; we have redefined this cluster as about 10-100 times larger (in projected area) than was previously realized.