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MassiveYoungStar-FormingComplexStdyinIR&X-Rays:MYStIXProbComplexMbrs

Metadata Updated: April 10, 2026

The Massive Young Star-forming complex Study in Infrared and X-rays (MYStIX) project requires samples of young stars that are likely members of 20 nearby Galactic massive star-forming regions. Membership is inferred from statistical classification of X-ray sources, from detection of a robust infrared excess that is best explained by circumstellar dust in a disk or infalling envelope and from published spectral types that are unlikely to be found among field stars. This table contains the MYStIX membership lists, which total 31,549 probable complex members. In their reference paper, the authors describe in detail the statistical classification of X-ray sources via a "Naive Bayes Classifier". These membership lists provide the empirical foundation for subsequent MYStIX science studies. The MYStIX project, described by Feigelson et al. (2013, ApJS, 209, 26), seeks to identify and study samples of young stars in 20 nearby (0.4 < D < 3.6kpc) Galactic massive star-forming regions (MSFRs). These samples are derived using X-ray data from the Chandra X-ray Observatory, near-infrared (NIR) photometry from the United Kingdom InfraRed Telescope (UKIRT) and from the Two Micron All Sky Survey (2MASS), mid-infrared (MIR) photometry from the Spitzer Space Telescope, and from published spectroscopically-identified massive stars. The purpose of this study is to describe the authors' efforts to minimize contaminants in the MYStIX catalogs of young stars. They refer to these latter objects as the "MYStIX Probable Complex Members" or MPCMs. This table contains the combined MPCM catalog for all 20 of the MYStIX MSFRs. This MPCM catalog is the union of three sets of probable members identified by three different established methods for identifying young stars (see Feigelson et al. 2013, ApJS, 209, 26, Fig. 3). Most of the X-ray information on the MPCMs (with the exception of the X-ray luminosities and absorbing column densities obtained using XPHOT) was produced by the ACIS Extract (AE) software package (Broos et al. 2010, ApJ, 714, 1582 and 2012, Astrophysics Source Code Library, 1203.001). The AE software and User's Guide are available at <a href="http://www.astro.psu.edu/xray/acis/acis_analysis.html">http://www.astro.psu.edu/xray/acis/acis_analysis.html</a>;. X-ray quantities using the 'fb' prefix are for the full or total energy band from 0.5 - 8.0 keV, those using the 'sb' prefix are for the soft band from 0.5 - 2.0 keV, and those using the 'hb' prefix are for the hard band from 2.0 - 8.0 keV. L. K. Townsley and P. S. Broos (2013, in preparation) and Kuhn et al. (2013, ApJS, 209, 27) identify a few very bright X-ray sources in each region that suffer from a type of instrumental non-linearity known as photon pile-up (<a href="http://cxc.harvard.edu/ciao/why/pileup_intro.html">http://cxc.harvard.edu/ciao/why/pileup_intro.html</a>;); X-ray properties reported for those sources are biased and should be used with caution. This table was created by the HEASARC in February 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/209/32">CDS Catalog J/ApJS/209/32</a> file mpcm.dat. This is a service provided by NASA HEASARC .

Access & Use Information

Public: This dataset is intended for public access and use. License: See this page for license information.

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Dates

Metadata Created Date April 11, 2025
Metadata Updated Date April 10, 2026

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date April 10, 2026
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/mystixmpcm
Data Last Modified 2026-04-06
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id e355c67f-ac9b-4074-8b7d-c93d24b29e97
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL ivo://nasa.heasarc/mystixmpcm
License https://www.usa.gov/government-works
Program Code 026:000
Source Datajson Identifier True
Source Hash 2ffaacf30a6574157cd1694b83572ec1c2ace3ce5d26d7caf17037897c7aa26e
Source Schema Version 1.1

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