NGC 2264 XMM-Newton X-Ray Point Source Catalog

NGC 2264 XMM-Newton X-Ray Point Source Catalog NGC2264XMM ivo://nasa.heasarc/ngc2264xmm NASA/GSFC HEASARC Dahm et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains (some of) the results from an X-ray imaging survey of the young cluster NGC 2264, carried out with the European Photon Imaging Cameras (EPIC) on board the XMM-Newton spacecraft. XMM-Newton EPIC observations were made separately of the northern and southern portions of NGC 2264 on 2001 March 20 and 2002 March 17 - 18, respectively. Details concerning the two pointings are summarized in Table 1 of the reference paper. The nominal integration time was 42 ks for both observations. The three EPIC cameras were operated in full window mode. To prevent contamination of the X-ray images by the XUV and EUV emission of the optically and UV-bright sources in the field of view, the thick filter was used, which imposes a strong cut-off in the response at the lower energies. The X-ray data are merged with extant optical and near-infrared photometry, spectral classifications, H-alpha emission strengths, and rotation periods to examine the interrelationships between coronal and chromospheric activity, rotation, stellar mass, and internal structure for a statistically significant sample of pre-main-sequence stars. Out of the 316 distinct point-like sources that were detected at >= 3-sigma levels in one or more of six EPIC images, a total of 300 distinct X-ray sources can be identified with optical or near-infrared counterparts. The sources are concentrated within three regions of the cluster: in the vicinity of S Mon, within the large emission/reflection nebulosity southwest of S Mon, and along the broad ridge of molecular gas that extends from the Cone Nebula to the NGC 2264 IRS 2 field. From the extinction-corrected color-magnitude diagram of the cluster, ages and masses for the optically identified X-ray sources are derived. A median age of ~ 2.5 Myr and an apparent age dispersion of ~ 5 Myr are suggested by pre-main-sequence evolutionary models. The X-ray luminosity of the detected sources appears well-correlated with bolometric luminosity, although there is considerable scatter in the relationship. Stellar mass contributes significantly to this dispersion, while isochronal age and rotation do not. X-ray luminosity and mass are well correlated such that LX ~ (M/Msolar)1.5, which is similar to the relationship found within the younger Orion Nebula Cluster. No strong evidence is found for a correlation between E(H-K), the near-infrared color excess, and the fractional X-ray luminosity, which suggests that optically thick dust disks have little direct influence on the observed X-ray activity levels. Among the X-ray-detected weak-line T Tauri stars, the fractional X-ray luminosity, LX/Lbol, is moderately well correlated with the fractional H-alpha luminosity, LH(alpha)/Lbol, but only at the 2-sigma level of significance. The cumulative distribution functions for the X-ray luminosities of the X-ray-detected classical and weak-line T Tauri stars within the cluster are comparable, assuming the demarcation between the two classes is at an H-alpha equivalent width of 10 Angstroms. However, if the non-detections in X-rays for the entire sample of H-alpha emitters known within the cluster are taken into account, then the cumulative distribution functions of these two groups are clearly different, such that classical T Tauri stars are underdetected by at least a factor of 2 relative to the weak-line T Tauri stars. Examining a small subsample of X-ray-detected stars that are probable accretors based on the presence of strong H-alpha emission and near-infrared excess, the authors conclude that definitive non-accretors are ~ 1.6 times more X-ray luminous than their accreting counterparts. In agreement with earlier published findings for the Orion Nebula Cluster, the authors find a slight positive correlation (valid at the 2-sigma confidence level) between LX/Lbol and the rotation period in NGC 2264 stars. The lack of a strong anti-correlation between X-ray activity and rotation period in the stellar population of NGC 2264 suggests that either the deeply convective T Tauri stars are rotationally saturated or that the physical mechanism responsible for generating magnetic fields in pre-main-sequence stars is distinct from the one that operates in evolved main-sequence stars. This table was created by the HEASARC in September 2007 based on the electronic version of Table 2 from the reference paper which was obtained from the electronic AJ site. This is a service provided by NASA HEASARC . 2007AJ....134..999D https://heasarc.gsfc.nasa.gov/W3Browse/all/ngc2264xmm.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=ngc2264xmm& GET text/xml 180 99999 true 100.22666667 9.33472222 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=ngc2264xmm GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_ngc2264xmm&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.0166666666666667 X-ray Optical Infrared public ngc2264xmm NGC 2264 XMM-Newton X-Ray Point Source Catalog name Catalog Source Designation meta.id;meta.main char nullable optical_name Optical Source Designation meta.id.cross char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable count_rate Count Rate (EPIC PN Unless Flag Indicate Otherwise) ct/s phot.count;em.X-ray double nullable count_rate_error Uncertainty in Count Rate ct/s stat.error;phot.count;em.X-ray double nullable log_lx Log of Foreground Extinction-Corrected X-Ray Luminosity (in Units of erg/s) log(erg/s) phys.luminosity;em.X-ray double nullable vmag The V Band Magnitude mag phot.mag;em.opt.V double nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable jmag 2MASS J Band Magnitude mag phot.mag;em.IR.J double nullable extraction_fraction Throughput of the Extraction Aperture percent instr.det.psf short nullable bii Galactic Latitude degree pos.galactic.lat double nullable mass Stellar Mass (Solar Mass Units) Solar_Mass phys.mass double nullable source_flag Flag [l] Indicates Adaptive Optics Binary meta.code char nullable log_lx_error Uncertainty in Log_Lx log(erg/s) stat.error;phys.luminosity;em.X-ray double nullable jh_color 2MASS (J-H) Color mag phot.color;em.IR.J;em.IR.H double nullable vmag_extinction V Band Extinction mag phys.absorption;em.opt.V double nullable vr_color The (V-R_C_) Color mag phot.color;em.opt.V;em.opt.R double nullable alt_name Alternative Source Designation meta.id.assoc char nullable source_number Sequential Identification Number for Each X-Ray Source in Catalog meta.id short nullable log_age Log of the Stellar Age (in Units of years) log(yr) time.age double nullable exposure Effective Exposure Time (s) s time.duration;obs.exposure double nullable lii Galactic Longitude degree pos.galactic.lon double nullable count_rate_flag Flag [m] Indicates MOS Count Rate (Not EPIC PN) meta.code char nullable hk_color 2MASS (H-K_S_) Color mag phot.color;em.IR.H;em.IR.K double nullable halpha_ew Paper 1 H{alpha}-Equivalent Width (Angstrom) Angstrom spect.line.eqWidth;em.line.Halpha double nullable vi_color The (V-I_C_) Color mag phot.color;em.opt.V;em.opt.I double nullable