{"@type": "dcat:Dataset", "accessLevel": "public", "bureauCode": ["026:00"], "contactPoint": {"@type": "vcard:Contact", "fn": "HEASARC Help Desk", "hasEmail": "mailto:andrew.ptak@nasa.gov"}, "description": "Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until now been reported and there has been no large survey comparable to that based upon the ROSAT All-Sky Survey (RASS). A limited survey of X-ray sources, consisting of all public XMM observations (2XMMi) and slew survey data (XMMSL1), is now available. The X-ray counterparts to hot, massive stars have been searched for in these catalogs. About 300 OB stars were detected with XMM. Half of them were bright enough for a spectral analysis to be possible, and we make available the detailed spectral properties that were derived. The X-ray spectra of O stars are represented well by low (< 1 keV) temperature components and seem to indicate that an absorption column is present in addition to the interstellar contribution. The X-ray fluxes are well correlated with the bolometric fluxes, with a scatter comparable to that of the RASS studies and thus larger than found previously with XMM for some individual clusters. These results contrast with those of B stars that exhibit a large scatter in the L<sub>X</sub> - L<sub>bol</sub> relation, no additional absorption being found, and the fits indicate a plasma at higher temperatures. Variability (either within one exposure or between multiple exposures) was also investigated whenever possible: short-term variations are far more rare than long-term ones (the former affects a few percent of the sample, while the latter concerns between one third and two thirds of the sources). This is a catalog of X-ray emitters amongst early-type stars following a correlation between the Reed (2003, AJ, 125, 2531) Catalog of galactic OB Stars and the 2XMMi Catalog (Watson et al. 2009, A&A, 493, 339). See the reference paper for more details. This table was created by the HEASARC in November 2009 based on CDS table J/A+A/506/1055 file table1.dat. This is a service provided by NASA HEASARC .", "distribution": [{"@type": "dcat:Distribution", "downloadURL": "https://heasarc.gsfc.nasa.gov/W3Browse/all/xmmobstars.html", "format": "HTML", "mediaType": "text/html"}, {"@type": "dcat:Distribution", "downloadURL": "https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=xmmobstars&", "format": "BIN", "mediaType": "application/octet-stream"}], "identifier": "ivo://nasa.heasarc/xmmobstars", "keyword": ["__"], "landingPage": "ivo://nasa.heasarc/xmmobstars", "license": "https://www.usa.gov/government-works", "modified": "2026-05-11", "programCode": ["026:000"], "publisher": {"@type": "org:Organization", "name": "High Energy Astrophysics Science Archive Research Center"}, "theme": ["Astrophysics"], "title": "XMM-Newton OB Stars Catalog"}