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dc.contributor.authorWright, Nick
dc.contributor.authorDrake, J.
dc.contributor.authorDrew, J.E.
dc.contributor.authorVink, J.S.
dc.date.accessioned2010-04-19T10:39:54Z
dc.date.available2010-04-19T10:39:54Z
dc.date.issued2010
dc.identifier.citationWright , N , Drake , J , Drew , J E & Vink , J S 2010 , ' The massive star-forming region Cygnus OB2. II - integrated stellar properties and the star formation history ' , The Astrophysical Journal , vol. 713 , no. 2 , pp. 871-882 . https://doi.org/10.1088/0004-637X/713/2/871
dc.identifier.issn0004-637X
dc.identifier.otherPURE: 172361
dc.identifier.otherPURE UUID: 547a8fb6-8e1c-4702-8ee4-9fdf026fd3d1
dc.identifier.otherdspace: 2299/4421
dc.identifier.otherScopus: 77950239077
dc.identifier.urihttp://hdl.handle.net/2299/4421
dc.descriptionThe definitive article can be found at: http://iopscience.iop.org/0004-637X/713/2/871 Copyright American Astronomical Society. [Full text of this article is not available in the UHRA]
dc.description.abstractCygnus OB2 is the nearest example of a massive star-forming region (SFR), containing over 50 O-type stars and hundreds of B-type stars. We have analyzed the properties of young stars in two fields in Cyg OB2 using the recently published deep catalog of Chandra X-ray point sources with complementary optical and near-IR photometry. Our sample is complete to ~1 M (excluding A- and B-type stars that do not emit X-rays), making this the deepest study of the stellar properties and star formation history in Cyg OB2 to date. From Siess et al. isochrone fits to the near-IR color-magnitude diagram, we derive ages of 3.5+0.75 –1.0 and 5.25+1.5 –1.0 Myr for sources in the two fields, both with considerable spreads around the pre-main-sequence isochrones. The presence of a stellar population somewhat older than the present-day O-type stars, also fits in with the low fraction of sources with inner circumstellar disks (as traced by the K-band excess) that we find to be very low, but appropriate for a population of age ~5 Myr. We also find that the region lacks a population of highly embedded sources that is often observed in young SFRs, suggesting star formation in the vicinity has declined. We measure the stellar mass functions (MFs) in this limit and find a power-law slope of Γ = –1.09 ± 0.13, in good agreement with the global mean value estimated by Kroupa. A steepening of the slope at higher masses is observed and suggested as due to the presence of the previous generation of stars that have lost their most massive members. Finally, combining our MF and an estimate of the radial density profile of the association suggests a total mass of Cyg OB2 of ~3 × 104 M , similar to that of many of our Galaxy's most massive SFRs.en
dc.language.isoeng
dc.relation.ispartofThe Astrophysical Journal
dc.rights/dk/atira/pure/core/openaccesspermission/open
dc.titleThe massive star-forming region Cygnus OB2. II - integrated stellar properties and the star formation historyen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionScience & Technology Research Institute
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Accepted Version
rioxxterms.versionVoR
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1088/0004-637X/713/2/871
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeopenAccess


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