F . R . Harnden

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We present analysis of a series of ROSAT High Resolution Imager (HRI) observations of 16 X-ray detections from the Einstein Slew Survey (ESS). The data were taken to resolve ambiguous ESS identiÐcations based on optical spectroscopy. For 10 of the 16 detections, the previous identiÐcation has been conÐrmedÈsix with solar-type stars (spectral types FÈK), one(More)
We investigate the spatial distribution of X-ray emitting plasma in a sample of young Orion Nebula Cluster stars by modulation of their X-ray light-curves due to stellar rotation. The study, part of the Chandra Orion Ultradeep Project (COUP), is made possible by the exceptional length of the observation: 10 days of ACIS integration during a time span of 13(More)
1 INAF Osservatorio Astronomico di Palermo G.S.Vaiana, Piazza del Parlamento 1, I-90134 Palermo, ITALY 2 ESO, Casilla 19001, Santiago, Chile 3 Observatorio Astronomico de Lisboa, Tapada de Ajuda, 1349-018 Lisboa, Portugal 4 SIM/IDL, Fac. de Ciências da Universidade de Lisboa, Ed. C8 Campo Grande, 1749-016 Lisboa, Portugal 5 Smithsonian Astrophysical(More)
We describe a new technique for the characterization of low{resolution X-ray spectra, based on generalized colors deened by means of a principal component analysis. Application of the method to a sample of optically and radio-selected Einstein Observatory X-ray sources yields groups that are dominated either by stars or by extragalactic sources. The method(More)
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 × 30 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(More)
We present the analysis and interpretation of an observation of the flare star AD Leo (dM3e) with the Low-Energy Transmission Grating of Chandra. The high resolution X-ray spectrum – dominated by emission lines from OVII–VIII, Ne IX–X, and FeXVII–FeXIX – allowed us to infer the plasma emission measure distribution (EMD) vs. temperature, and the abundances(More)
We present a description of the data reduction methods and the derived catalog of more than 1600 X-ray point sources from the exceptionally deep 2003 January Chandra X-Ray Observatory (Chandra) observation of the Orion Nebula Cluster and embedded populations around OMC-1. The observation was obtained withChandra’s Advanced CCD Imaging Spectrometer (ACIS)(More)
We present a ROSAT High Resolution Imager (HRI) observation of the star forming region NGC 2264. The analysis has detected more than 40 X-ray sources with Lx in the range 10 30 ?10 31 erg/sec. The high spatial resolution of the detector allows us to resolve sources that were confused in previous IPC and PSPC observations of the same region. Moreover, we(More)
The Chandra Multi-wavelength Project (ChaMP) is a wide-area (~14 deg 2) survey of serendipitous Chandra X-ray sources, aiming to establish fair statistical samples covering a wide range of characteristics (such as absorbed AGNs, high z clusters of galaxies) at flux levels (f X ~ 10-15 – 10-14 erg sec-1 cm-2) intermediate between the Chandra Deep surveys and(More)