M 17 Chandra X-Ray Point Source Catalog

M 17 Chandra X-Ray Point Source Catalog M17CXO ivo://nasa.heasarc/m17cxo NASA/GSFC HEASARC Broos 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 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 LX < 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 AV > 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 LX ~ 10-7 Lbol. 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 . 2007ApJS..169..353B https://heasarc.gsfc.nasa.gov/W3Browse/all/m17cxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=m17cxo& GET text/xml 180 99999 true 275.17276 -16.310233 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=m17cxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_m17cxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public m17cxo M 17 Chandra X-Ray Point Source Catalog name IAUC Source Designation meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable counts Net Extracted Total (0.5-8keV) Band Counts ct phot;em.X-ray double nullable counts_error Averaged Upper and Lower 1-Sigma Error in Total Band Counts ct stat.error;phot;em.X-ray double nullable log_lx Log of Absorption-Corrected Total Band (0.5-8keV) Luminosity (in erg/s) log(erg/s) phys.luminosity;em.X-ray double nullable twomass_name 2MASS Source Designation meta.id.cross char nullable log_nh_pos_err Upper 90% Confidence Level in Log_NH log(cm^-2) stat.error;phys.columnDensity double nullable log_bck_prob Log of Probability That Total Band Extracted Counts Are Solely from Background stat.probability double nullable alt_name Alternative Source Designation meta.id char nullable source_flag Flag [P,T] Indicates Primary or Tentative Source meta.code char nullable spect_type Spectral Type src.spType char nullable significance Photometric Significance stat.likelihood double nullable hmag_flag Flag Indicates Photometry Error Exceeds 0.1 mag in Hmag meta.code;phot.mag;em.IR.H char nullable log_hb_lx Log of Absorption-Corrected Hard Band (2-8keV) Luminosity (in erg/s) log(erg/s) phys.luminosity;em.X-ray.medium double nullable source_variable_flag Flag Indicates Total (2-8keV) Band Variability Characterization meta.code char nullable log_em_neg_err Lower 90% Confidence Level in Log_EM log(cm^-3) stat.error;phys.emissMeasure double nullable glimpse_name GLIMPSE Source Designation meta.id.cross char nullable hb_counts Net Extracted Hard (2-8keV) Band Counts ct phot;em.X-ray.medium double nullable log_em_pos_err Upper 90% Confidence Level in Log_EM log(cm^-3) stat.error;phys.emissMeasure double nullable spectral_index_neg_err Lower 90% Confidence Level in Gamma stat.error;spect.index;em.X-ray double nullable spectral_index_pos_err Upper 90% Confidence Level in Gamma stat.error;spect.index;em.X-ray double nullable irac_3p6_um_mag GLIMPSE 3.6-micron Band Magnitude mag phot.mag;em.IR.3-4um double nullable log_nh_flag Flag [e] Indicates Model Parameter Frozen in the NH Fit meta.code;phys.columnDensity char nullable jmag_flag Flag Indicates Photometry Error Exceeds 0.1 mag in Jmag meta.code;phot.mag;em.IR.J char nullable irac_5p8_um_mag GLIMPSE 5.8-micron Band Magnitude mag phot.mag;em.IR.4-8um double nullable log_nh Log of Best Fit H I Column Density log(cm^-2) phys.columnDensity double nullable error_radius Position Error (arcsec) arcsec stat.error;pos double nullable spectral_index Best Fit Power Law Photon Index spect.index;em.X-ray double nullable apec_kt_neg_err Lower 90% Confidence Level in kT (keV) keV stat.error;phys.temperature double nullable spectral_flag Flag [2T] Indicates Two-Temperature Model Used (2nd Temperature in Parentheses) meta.code char nullable off_axis Off-Axis Angle (arcmin) arcmin instr.offset double nullable cen_number Chini, Elsaesser & Neckel (1980) Identification meta.id.cross int nullable source_anomaly_flag Flag Indicates Source Anomalies meta.code char nullable lii Galactic Longitude degree pos.galactic.lon double nullable sirius_number_flag Flag [a] Indicates Source Outside the SIRIUS Field of View meta.code;src char nullable ir_match_flags Flags Indicates 2MASS/SIRIUS/GLIMPSE Source Match Ambiguity meta.code;em.IR char nullable spect_type_flag Flag [H] Indicates Spectral Type from Hanson, Howarth & Conti (1997) meta.code;src.spType char nullable hmag The H Band Magnitude mag phot.mag;em.IR.H double nullable source_number Sequential Identification Number for Each Source in Catalog, Sorted by RA meta.id short nullable kmag The K Band Magnitude mag phot.mag;em.IR.K double nullable apec_kt_flag Flag [e] Indicates Model Parameter Frozen in the Plasma Temperature Fit meta.code;phys.temperature char nullable kmag_flag Photometry Error Exceeds 0.1 mag in Kmag meta.code;phot.mag;em.IR.K char nullable log_lx_obs Log of Total Band (0.5-8keV) Luminosity (in erg/s) log(erg/s) phys.luminosity;em.X-ray double nullable twomass_flags Flag Indicates 2MASS Source Contamination and Confusion meta.code.qual char nullable hhc_number Hanson, Howarth & Conti (1997) Identification meta.id.cross short nullable jmag_limit Limit Flag for Jmag meta.code;phot.mag;em.IR.J char nullable hmag_limit Limit Flag for Hmag meta.code;phot.mag;em.IR.H char nullable log_pl_norm_pos_err Upper 90% Confidence Level in Log_Pl_Norm stat.error;stat.fit.param double nullable log_hb_lx_obs Log of Hard Band (2-8keV) Luminosity (in erg/s) log(erg/s) phys.luminosity;em.X-ray.medium double nullable exposure Effective Exposure (s) s time.duration;obs.exposure double nullable apec_kt_pos_err Upper 90% Confidence Level in kT (keV) keV stat.error;phys.temperature double nullable irac_4p5_um_mag GLIMPSE 4.5-micron Band Magnitude mag phot.mag;em.IR.4-8um double nullable log_sb_lx_obs Log of Soft Band (0.5-2keV) Luminosity (in erg/s) log(erg/s) phys.luminosity;em.X-ray.soft double nullable bii Galactic Latitude degree pos.galactic.lat double nullable bck_counts Background Extracted Total (0.5-8keV) Band Counts ct phot;instr.background;em.X-ray double nullable median_energy Background-Corrected Total (0.5-8keV) Band Median Photon Energy (keV) keV phys.energy double nullable log_pl_norm Log of Model Spectrum Power Law Normalization stat.fit.param double nullable irac_8p0_um_mag GLIMPSE 8.0-micron Band Magnitude mag phot.mag;em.IR.4-8um double nullable log_pl_norm_neg_err Lower 90% Confidence Level in Log_Pl_Norm stat.error;stat.fit.param double nullable log_bck_prob_limit Limit Flag for logP meta.code;stat.probability char nullable sirius_number SIRIUS Catalog Running Sequence Number meta.id.cross char nullable log_em Log of Model Emission Measure (in cm^-3) log(cm^-3) phys.emissMeasure double nullable psf_fraction PSF Fraction Enclosed within the Extraction Region instr.det.psf double nullable jmag The J Band Magnitude mag phot.mag;em.IR.J double nullable apec_kt Best Fit Plasma Temperature (keV) keV phys.temperature double nullable ref_ir_match Code Indicates Additional Notes in Documentation meta.ref short nullable log_nh_neg_err Lower 90% Confidence Level in Log_NH log(cm^-2) stat.error;phys.columnDensity double nullable kmag_limit Limit Flag for Kmag meta.code;phot.mag;em.IR.K char 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