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Chandra X-ray Observation of the Orion Nebula Cluster. I Detection, Identification and Determination of X-ray Luminosities

E. Flaccomio·F. Damiani·G. Micela·S. Sciortino·F. R. Harnden Jr.·S. S. Murray·S. J. Wolk
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Abstract

In this first of two companion papers on the Orion Nebula Cluster (ONC), we present our analysis of a 63 Ksec Chandra HRC-I observation that yielded 742 X-ray detections within the 30'x30' field of view. To facilitate our interpretation of the X-ray image, here we collect a multi-wavelength catalog of nearly 2900 known objects in the region by combining 17 different catalogs from the recent literature. We define two reference groups: an infrared sample, containing all objects detected in the K band, and an optical sample comprising low extinction, well characterized ONC members. We show for both samples that field object contamination is generally low. Our X-ray sources are primarily low mass ONC members. The detection rate for optical sample stars increases monotonically with stellar mass from zero at the brown dwarf limit to ~100% for the most massive stars but shows a pronounced dip between 2 and 10 solar masses. We determine L_X and L_X/L_{bol} for all stars in our optical sample and utilize this information in our companion paper to study correlations between X-ray activity and other stellar parameters.

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E. Flaccomio, F. Damiani, G. Micela, S. Sciortino, F. R. Harnden Jr., S. S. Murray, S. J. Wolk. 2002-08-27. Chandra X-ray Observation of the Orion Nebula Cluster. I Detection, Identification and Determination of X-ray Luminosities. https://doi.org/10.1086/344535

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