NGC 6231 XMM-Newton X-Ray Source Catalog

NGC 6231 XMM-Newton X-Ray Source Catalog NGC6231XMM ivo://nasa.heasarc/ngc6231xmm NASA/GSFC HEASARC Sana et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the results of an X-ray campaign towards the young open cluster NGC 6231. The XMM-Newton observations, of a total duration of ~ 180 ks, reveal that NGC 6231 is very rich in the X-ray domain too. Indeed, 610 X-ray sources were detected in the present field of view, centered on the colliding wind binary HD 152248 in the cluster core (RA, Dec J2000.0 of 16 54 10.06, -41 49 30.1). The limiting sensitivity of this survey is approximately 6 x 10^-15erg/s/cm2 but clearly depends on the location in the field of view and on the source spectrum. Using different existing catalogs, over 85% of the X-ray sources could be associated with at least one optical and/or infrared counterpart within a limited cross-correlation radius of 2.5 or 3-arcsec according to the optical/IR catalog used. The surface density distribution of the X-ray sources presents a slight N-S elongation. Once corrected for the spatial sensitivity variation of the EPIC instruments, the radial profile of the source surface density is well described by a King profile with a central density of about 8 sources per arcmin2 and a core radius close to 3.1 arcminutes. The distribution of the X-ray sources seems closely related to the optical source distribution. The expected number of foreground and background sources should represent about 9% of the detected sources, thus strongly suggesting that most of the observed X-ray emitters are physically belonging to NGC 6231. Finally, beside a few bright but soft objects -- corresponding to the early-type stars of the cluster -- most of the sources are relatively faint (~5 x 10-15 erg/s/cm2) with an energy distribution peaked around 1.0 - 2.0 keV. The catalog of the 610 X-ray sources detected in the 30'-diameter field of view of XMM-Newton is presented here, including the equatorial coordinates, logarithmic likelihoods and count rates for the three EPIC instruments and for various energy ranges, as well as the cross-identification of the X-ray sources with various optical/infrared catalogs (2MASS, GSC2.2, USNO B1.0, SSB06) and their most commonly used names (HD/HDE, CD, CPD, Segg., SBL98, Braes), with only the closest identifications being reported here. This table was created by the HEASARC in March 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/454/1047">CDS catalog J/A+A/454/1047</a> files table3.dat and table6.dat. This is a service provided by NASA HEASARC . 2006A&A...454.1047S https://heasarc.gsfc.nasa.gov/W3Browse/all/ngc6231xmm.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=ngc6231xmm& GET text/xml 180 99999 true 253.48841667 -42.06069444 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=ngc6231xmm GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_ngc6231xmm&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.0166666666666667 Infrared Optical X-ray public ngc6231xmm NGC 6231 XMM-Newton X-Ray Source Catalog name Recommended XMM Source Designation meta.id char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable pn_count_rate PN: Count Rate in 0.5-10.0 keV ct/s double nullable twomass_name 2MASS (<II/246>) Source Designation char nullable jmag 2MASS: J Magnitude mag 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 kmag 2MASS: K Magnitude mag double nullable comments Comments and Warnings char nullable r1_mag USNO B1.0: R1 Magnitude mag double nullable m1_mb_count_rate M1: Count Rate in 1.0-2.5 keV ct/s double nullable offset_2mass_xmm 2MASS: Correlation Distance (arcsec) arcsec double nullable pn_hr2 PN: Second Hardness Ratio double nullable m1_mb_count_rate_error M1: Error on Count Rate in 1.0-2.5 keV ct/s double nullable instruments_used Combination of Instruments Used char nullable braes_number CI: Braes Number short nullable pn_hr2_error PN: Error on Second Hardness Ratio double nullable m2_hb_count_rate_error M2: Error on Count Rate in 2.5-10.0 keV ct/s double nullable m1_count_rate_error M1: Error on Count Rate in 0.5-10.0 keV ct/s double nullable m1_hr1_error M1: Error on First Hardness Ratio double nullable source_number Sequential Identification Number for Each X-Ray Source in Catalog meta.id;meta.main short nullable pn_count_rate_error PN: Error on Count Rate in 0.5-10.0 keV ct/s double nullable m1_sb_count_rate M1: Count Rate in 0.5-1.0 keV ct/s double nullable bmag GSC2.2: B Magnitude mag phot.mag;em.opt.B double nullable m1_hb_count_rate M1: Count Rate in 2.5-10.0 keV ct/s double nullable offset_ssb06_xmm SSB06: Correlation Distance (arcsec) arcsec double nullable vi_color SSB06: V-I Color mag double nullable m2_hr1 M2: First Hardness Ratio double nullable m2_sb_count_rate_error M2: Error on Count Rate in 0.5-1.0 keV ct/s double nullable m2_hr2 M2: Second Hardness Ratio double nullable pn_hb_count_rate_error PN: Error on Count Rate in 2.5-10.0 keV ct/s double nullable m2_mb_count_rate M2: Count Rate in 1.0-2.5keV ct/s double nullable m2_likelihood M2: Equivalent Likelihood L2 double nullable hmag 2MASS: H Magnitude mag double nullable bii Galactic Latitude degree pos.galactic.lat double nullable extent_flag Flag Indicates Extended Source char nullable m1_hr1 M1: First Hardness Ratio double nullable bv_color SSB06: B-V Color mag phot.color;em.opt.B;em.opt.V double nullable ssb06_number SSB06 (Sung et al., 2006, in prep.) Source Designation char nullable ssb06_flag Flag Indicates Related Stars Saturated in SSB06 Data, Data Taken from SBL98 char nullable segg_number CI: Seggewiss (1968VeBon..79....1S) Number NGC 6231 NNN in SIMBAD short nullable lii Galactic Longitude degree pos.galactic.lon double nullable alt_name Catalog Source Designation meta.id char nullable b1_mag USNO B1.0: B1 Magnitude mag double nullable m1_hb_count_rate_error M1: Error on Count Rate in 2.5-10.0 keV ct/s double nullable cpd_m41number CI: CPD Number (in format CPD-41 NNNN) short nullable vmag GSC2.2: V Magnitude mag phot.mag;em.opt.V double nullable pn_hr1_error PN: Error on First Hardness Ratio double nullable m2_count_rate M2: Count Rate in 0.5-10.0 keV ct/s double nullable error_radius Error on Source Position (arcsec) arcsec stat.error;pos double nullable m2_sb_count_rate M2: Count Rate in 0.5-1.0 keV ct/s double nullable gsc2p2_name GSC2.2 (<I/271>) Source Designation char nullable cd_multiplicity_index Flag Indicates Multiplicity Index on CD char nullable b2_mag USNO B1.0: B2 Magnitude mag double nullable rmag GSC2.2: R Magnitude mag phot.mag;em.opt.R double nullable pn_hb_count_rate PN: Count Rate in 2.5-10.0 keV ct/s double nullable ub_color SSB06: U-B Color mag phot.color;em.opt.U;em.opt.B double nullable offset_usnob1_xmm USNO B1.0: Correlation Distance (arcsec) arcsec double nullable epic_likelihood EPIC: Total Equivalent Likelihood L2 double nullable offset_gsc2p2_xmm GSC2.2: Correlation Distance (arcsec) arcsec double nullable sbl98_number CI: Sung et al., 1998, Cat.<J/AJ/115/734> Number, Cl* NGC 6231 SBL NNN in SIMBAD int nullable pn_likelihood PN: Equivalent Likelihood L2 double nullable pn_sb_count_rate_error PN: Error on Count Rate in 0.5-1.0 keV ct/s double nullable m2_mb_count_rate_error M2: Error on Count Rate in 1.0-2.5keV ct/s double nullable usnob1_name USNO B1.0 (<I/284>) Source Designation char nullable m2_hr1_error M2: Error on First Hardness Ratio double nullable m1_hr2 M1: Second Hardness Ratio double nullable m1_count_rate M1: Count Rate in 0.5-10.0 keV ct/s double nullable imag USNO B1.0: I Magnitude mag phot.mag;em.opt.I double nullable hd_number CI: HD/HDE Number int nullable m2_hb_count_rate M2: Count Rate in 2.5-10.0 keV ct/s double nullable pn_sb_count_rate PN: Count Rate in 0.5-1.0 keV ct/s double nullable m1_hr2_error M1: Error on Second Hardness Ratio double nullable cd_m41number CI: CD Number (in format CD-41 NNNNN) int nullable m2_hr2_errorr M2: Error on Second Hardness Ratio double nullable r2_mag USNO B1.0: R2 Magnitude mag double nullable m2_count_rate_error M2: Error on Count Rate in 0.5-10.0 keV ct/s double nullable m1_likelihood M1: Equivalent Likelihood L2 double nullable m1_sb_count_rate_error M1: Error on Count Rate in 0.5-1.0 keV ct/s double nullable pn_mb_count_rate PN: Count Rate in 1.0-2.5 keV ct/s double nullable pn_mb_count_rate_error PN: Error on Count Rate in 1.0-2.5 keV ct/s double nullable vmag_ssb06 SSB06: V Magnitude mag double nullable pn_hr1 PN: First Hardness Ratio double nullable