This table contains some of the results from the first paper of a series devoted to the Lambda Orionis star-forming region, Orion's Head, from the X-ray perspective. The final aim of this research is to provide a comprehensive view of this complex region, which includes several distinct associations and dark clouds. The authors aim to uncover the population of the central, young star cluster Collinder 69, and in particular to find those diskless Class III pre-main sequence objects which have not been identified by previous surveys based on near- and mid-infrared searches, and to establish the X-ray luminosity function for the association. The authors have combined two exposures taken with the XMM-Newton satellite with an exhaustive data set of optical, near- and mid-infrared photometry to assess the membership of the X-ray sources based on different color-color and color-magnitude diagrams, as well as other properties, such as effective temperatures, masses and bolometric luminosities derived from spectral energy distribution fitting and comparison with theoretical isochrones. The presence of circumstellar disks is discussed using mid-infrared photometry from the Spitzer Space Telescope. This table contains the XMM-Newton X-ray point source catalog for all sources detected in the EPIC observations of the Collinder 69, East and West Fields (C69E and C69W), respectively, with maximum likelihood (ML) values > 15.0. A companion HEASARC Browse table COLL69OID contains optical and infrared data as well as membership information on counterparts to these X-ray sources. This table was created by the HEASARC in July 2011 based on the electronic versions of Tables 3 and 4 from the reference paper which were obtained from the CDS (their catalog J/A+A/526/A21 files table3.dat and table4.dat). This is a service provided by NASA HEASARC .

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (IRAC 3.6 and 4.5 micron) time series photometry of the Orion Nebula Cluster plus smaller fields in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. YSOVAR is a sister project to the Coordinated Synoptic Investigation of NGC 2264 (CSI 2264; Cody et al. 2014). Initial YSOVAR results were described in Morales-Calderon et al. (2011). Rebull et al. (2014) describes the details of target selection, data reduction, and other conventions established for this project.

This table contains the machine-readable version of the Third Reference Catalogue of Bright Galaxies (RC3) by G. de Vaucouleurs, A. de Vacouleurs, H.G. Corwin, R.J. Buta, P. Fouque, and G. Paturel, originally published by Springer-Verlag in 1991, and including some corrections and additions made by Corwin et al. (1994, AJ, 108, 2128). Only brief parameter descriptions are given in this help file. Detailed information about, for example, how certain quantities were derived, or exactly what a given code means, can be found in the printed version of RC3. This table was created by the HEASARC in March 2007 based on CDS table VII/155/rc3, and replaced an earlier version which did not contain the corrections made by Corwin et al. This is a service provided by NASA HEASARC .

This catalog presents some of the results from 3 deep ROSAT High Resolution Imager (HRI) observations of the Orion Nebula star-forming region. The fields covered by the X-ray images contain over 1500 catalogued stars in a roughly 0.8 square degree region centered on the Trapezium. In all, 389 distinct X-ray sources were detected, at least two-thirds of which were associated with a single proper-motion cluster member. X-ray emission was detected from stars of all spectral types, from the massive O- and B-type components of the Trapezium to the coolest, low-mass pre-main-sequence (PMS) stars. In the research paper in which these data were presented (Gagne et al. 1995), the authors focussed primarily on X-ray emission from the late-type PMS stars. Of the ~100 late-type cluster members with measured spectral types, approximately three-fourths were detected; the authors derived X-ray luminosity upper limits for the remaining stars. They found that coronal X-ray emission appeared to turn on at around a spectral type of F6, with the upper envelope of activity increasing with decreasing effective temperature. The current database is a representation of Table 6 from Gagne et al. (1995) (notice that the data given in Tables 2 and 3 of this reference is included in the HEASARC database ORIONXRAY, q.v.) which lists X-ray and other data for 175 Orion stars for which spectral types, spectroscopic rotational velocities, and/or spot-modulated photometric rotational periods are available. The X-ray data (either detections or upper limits) are given in the form of X-ray luminosities log Lx and X-ray to bolometric luminosity ratios (log Lx/Lbol). The conversion factor from HRI counts to log Lx was derived for each star based on (i) an assumed 1 keV Raymond and Smith thermal spectrum, (ii) a distance of 440 pc, and (iii) a column density of 2 x 10²¹ cm^-2 per magnitude of visual extinction A(V), where accurate A(V) values are used when available, or otherwise a moderate absorption of 0.25 magnitudes is assumed. Notice that, for stars not identified as candidate optical counterparts in Tables 2 and 3 of Gagne et al. (the HEASARC database ORIONXRAY), the derived upper limit to the X-ray luminosity usually corresponds to the 3 sigma upper limit to the observed count rate. For a handful of stars in the Trapezium region where a star was eliminated as a candidate optical counterpart, despite being within the source search circle, because a more likely counterpart had a smaller position offset, the upper limit corresponds to either half the observed X-ray source count rate or to 3 sigma, whichever is the highest. Such cases are indicated in this database by the presence of the string "NN" in the parameter 'Note'. This is a service provided by NASA HEASARC .

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (IRAC 3.6 and 4.5 micron) time series photometry of the Orion Nebula Cluster plus smaller fields in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. YSOVAR is a sister project to the Coordinated Synoptic Investigation of NGC 2264 (CSI 2264; Cody et al. 2014). Initial YSOVAR results were described in Morales-Calderon et al. (2011). Rebull et al. (2014) describes the details of target selection, data reduction, and other conventions established for this project.

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (IRAC 3.6 and 4.5 micron) time series photometry of the Orion Nebula Cluster plus smaller fields in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. YSOVAR is a sister project to the Coordinated Synoptic Investigation of NGC 2264 (CSI 2264; Cody et al. 2014). Initial YSOVAR results were described in Morales-Calderon et al. (2011). Rebull et al. (2014) describes the details of target selection, data reduction, and other conventions established for this project.

This table contains some of the results from a Chandra ACIS observation of the stellar populations in and around the M17 H II region. The field reveals 886 sources (listed in the present table) with observed X-ray luminosities (uncorrected for absorption) between ~ 29.3 erg s^-1 < log L_X < 32.8 erg s^-1, 771 of which have stellar counterparts in infrared images. Spectral analysis results for the 598 brightest X-ray sources which have photometric significance of 2.0 or greater) are also given herein. For 546 of the X-ray sources, the fits used the "wabs(apec)" thermal plasma model in XSPEC assuming scaled 0.3 times solar photospheric abundances, while for the other 52 X-ray sources for which either the thermal model poorly described the data or required nonphysical parameters and the X-ray source was not identified with a known stellar counterpart, the fits used the "wabs(powerlaw)" model in XSPEC. In addition to the comprehensive tabulation of X-ray source properties, several other results were presented in the reference paper: 1. The X-ray luminosity function is calibrated to that of the Orion Nebula Cluster population to infer a total population of roughly 8000-10,000 stars in M17, one-third lying in the central NGC 6618 cluster. 2. About 40% of the ACIS sources are heavily obscured with A_V > 10 mag. Some are concentrated around well-studied star-forming regions -- IRS 5/UC1, the Kleinmann-Wright Object, and M17-North -- but most are distributed across the field. As previously shown, star formation appears to be widely distributed in the molecular clouds. X-ray emission is detected from 64 of the hundreds of Class I protostar candidates that can be identified by near- and mid-infrared colors. These constitute the most likely protostar candidates known in M17. 3. The spatial distribution of X-ray stars is complex: in addition to the central NGC 6618 cluster and well-known embedded groups, we find a new embedded cluster (designated M17-X), a 2 pc long arc of young stars along the southwest edge of the M17 H II region, and 0.1 pc substructure within various populations. These structures may indicate that the populations are dynamically young. 4. All (14/14) of the known O stars but only about half (19/34) of the known B0-B3 stars in the M17 field are detected. These stars exhibit the long-reported correlation between X-ray and bolometric luminosities of L_X ~ 10^-7 L_bol. While many O and early-B stars show the soft X-ray emission expected from microshocks in their winds or moderately hard emission that could be caused by magnetically channeled wind shocks, six of these stars exhibit very hard thermal plasma components (kT > 4 keV) that may be due to colliding wind binaries. More than 100 candidate new OB stars are found, including 28 X-ray detected intermediate- and high-mass protostar candidates with infrared excesses. 5. Only a small fraction (perhaps 10%) of X-ray selected high- and intermediate-mass stars exhibit K-band-emitting protoplanetary disks, providing further evidence that inner disks evolve very rapidly around more massive stars. This table was created by the HEASARC in December 2007 based on electronic versions of Tables 1, 2, 3, 4 and 5 of the reference paper which were obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (IRAC 3.6 and 4.5 micron) time series photometry of the Orion Nebula Cluster plus smaller fields in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. YSOVAR is a sister project to the Coordinated Synoptic Investigation of NGC 2264 (CSI 2264; Cody et al. 2014). Initial YSOVAR results were described in Morales-Calderon et al. (2011). Rebull et al. (2014) describes the details of target selection, data reduction, and other conventions established for this project.

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (IRAC 3.6 and 4.5 micron) time series photometry of the Orion Nebula Cluster plus smaller fields in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. YSOVAR is a sister project to the Coordinated Synoptic Investigation of NGC 2264 (CSI 2264; Cody et al. 2014). Initial YSOVAR results were described in Morales-Calderon et al. (2011). Rebull et al. (2014) describes the details of target selection, data reduction, and other conventions established for this project.