NGC2237CXO ivo://nasa.heasarc/ngc2237cxo NASA/GSFC HEASARC Wang et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The authors have obtained high spatial resolution Chandra X-ray images of the NGC 2237 young stellar cluster on the periphery of the Rosette Nebula. They detect 168 X-ray sources, 80% of which have stellar counterparts in USNO, Two Micron All Sky Survey, and deep FLAMINGOS images. These constitute the first census of the cluster members with 0.2 <~ M <~ 2 M<sub>sun</sub>. Star locations in near-infrared color-magnitude diagrams indicate a cluster age of around 2 Myr with a visual extinction of 1 <~ AV <~ 3 at 1.4 kpc, the distance of the Rosette Nebula's main cluster NGC 2244. The authors derive the K-band luminosity function and the X-ray luminosity function of the cluster, which indicate a population of ~ 400-600 stars. The X-ray-selected sample shows a K-excess disk frequency of 13%. The young Class II counterparts are aligned in an arc ~3 pc long suggestive of a triggered formation process induced by the O stars in NGC 2244. The diskless Class III sources are more dispersed. Several X-ray emitting stars are located inside the molecular cloud and around gaseous pillars projecting from the cloud. These stars, together with a previously unreported optical outflow originating inside the cloud, indicate that star formation is continuing at a low level and the cluster is still growing. This X-ray view of young stars on the western side of the Rosette Nebula complements the authors' earlier studies of the central cluster NGC 2244 and the embedded clusters on the eastern side of the Nebula. The large-scale distribution of the clusters and molecular material is consistent with a scenario in which the rich central NGC 2244 cluster formed first, and its expanding H II region triggered the formation of the now-unobscured satellite clusters Rosette Molecular Cloud (RMC) XA and NGC 2237. A large swept-up shell of material around the H II region is now in a second phase of collect-and-collapse fragmentation, leading to the recent formation of subclusters. Other clusters deeper in the molecular cloud appear unaffected by the Rosette Nebula expansion. Some sources which have information from published catalogs are listed by their source_number value below, where for convenience, [OI81] = Ogura & Ishida (1981, PASJ, 33, 149), [MJD95] = Massey, Johnson, & Degioia-Eastwood (1995, ApJ, 454, 151) and [BC02] = Berghofer & Christian (2002, A&A, 384, 890): <pre> 53 = [OI81] 14 = [MJD95] 104; spectral type B1V; pmRA=11.0 mas/yr, pmDE=-2.8 mas/yr; 54 = [OI81] 10 = [MJD95] 108; spectral type B2V; pmRA=-2.3 mas/yr, pmDE=-11.9 mas/yr; 61 = V539 Mon [OI81] 13 = [MJD95] 110; MSX6C G206.1821-02.3456; pmRA=2.8 mas/yr, pmDE=0.4 mas/yr; 71 = [OI81] 12 = [MJD95] 102; pmRA=6.8 mas/yr, pmDE=0.6 mas/yr; 128 = [OI81] 35 = [MJD95] 471; spectral type A2:; pmRA=-0.8 mas/yr, pmDE=3.6 mas/yr; 138 = [OI81] 36 = [MJD95] 497; spectral type B5; pmRA=6.5 mas/yr, pmDE=2.1 mas/yr; 141 = [MJD95] 498; pmRA=-3.0 mas/yr, pmDE=1.9 mas/yr; 149 = [BC02] 11; known X-ray source; log(Lx(ROSAT/PSPC))=31.01 erg/s; pmRA=0.6 mas/yr, pmDE=-12.6 mas/yr; 161 = [MJD95] 653; pmRA=-1.0 mas/yr, pmDE=-5.4 mas/yr </pre> This table was created by the HEASARC in July 2010 based on electronic versions of Tables 1, 2, 3 and 4 of the reference paper which were obtained from the electronic ApJ web site. To distinguish between the 130 X-ray sources in the primary sample (Table 1 of the reference paper) and the 38 X-ray sources in the tentative sample (Table 2 of the reference paper), the HEASARC has created a parameter called source_sample which is set to 'P' for the primary sources and to 'T' for the tentative sources. This is a service provided by NASA HEASARC . 2010ApJ...716..474W https://heasarc.gsfc.nasa.gov/W3Browse/all/ngc2237cxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=ngc2237cxo& GET text/xml 180 99999 true 97.695106 4.842502 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=ngc2237cxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_ngc2237cxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Infrared Optical X-ray public ngc2237cxo NGC 2237 Chandra X-Ray Point Source Catalog source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable name IAU-Style 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 Estimated Net 0.5-8 keV Counts ct phot;em.X-ray double nullable counts_error Poisson-Based 1-Sigma Uncertainty Counts ct stat.error;phot;em.X-ray double nullable log_lx Logarithm of Absorption-Corrected 0.5-8 keV Luminosity log(erg/s) phys.luminosity;em.X-ray double nullable twomass_name 2MASS Source Identification meta.id.cross char nullable jmag The J Band Magnitude mag phot.mag;em.IR.J double nullable log_nh Logarithm of Hydrogen Column Density log(cm^-2) phys.columnDensity double nullable log_bck_prob_limit Limit Flag for Log_Bck_Prob meta.code;stat.probability char nullable psf_fraction PSF Fraction Enclosed within Extraction Region instr.det.psf double nullable log_em_neg_err Lower 90%-Confidence Interval in Log_EM log(cm^-3) stat.error;phys.emissMeasure double nullable bmag The B-Band Magnitude mag phot.mag;em.opt.B double nullable log_em Logarithm of Emission Measure (Distance=1.4 kpc) log(cm^-3) phys.emissMeasure double nullable hmag The H Band Magnitude mag phot.mag;em.IR.H double 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char nullable apec_kt_neg_err Lower 90%-Confidence Interval in Plasma Temperature keV stat.error;phys.temperature double nullable median_energy Background-Corrected Median Photon Energy (keV) keV phys.energy double nullable source_anomaly_flag Flag [g] Indicates Source Anomaly meta.code char nullable source_variable_flag Flag [abc] Indicates Variability Characterization meta.code;src.var char nullable apec_kt_flag Flag Indicates Plasma Temperature Value Was Frozen in the Fit meta.code;phys.temperature char nullable log_nh_pos_err Upper 90%-Confidence Interval in Log_NH log(cm^-2) stat.error;phys.columnDensity double nullable log_bck_prob Logarithm of Background Probability stat.probability double nullable hb_counts Estimated Net 2-8 keV Counts ct phot;em.X-ray.medium double nullable twomass_flags Flags Indicates Quality of the 2MASS Photometry meta.code.qual;phot char nullable bck_counts Background 0.5-8 keV Counts ct phot;instr.background;em.X-ray double nullable log_nh_flag Flag Indicates Log_NH Value Was Frozen in the Fit meta.code;phys.columnDensity char nullable error_radius Estimated Random Component of Position Error (arcsec) arcsec stat.error;pos double nullable log_hb_lx_obs Logarithm of 2-8 keV Luminosity log(erg/s) phys.luminosity;em.X-ray.medium double nullable lii Galactic Longitude degree pos.galactic.lon double nullable apec_kt_pos_err Upper 90%-Confidence Interval in Plasma Temperature keV stat.error;phys.temperature double nullable apec_kt Plasma Temperature (keV) keV phys.temperature double nullable off_axis Off-Axis Angle (arcmin) arcmin instr.offset double nullable log_em_pos_err Upper 90%-Confidence Interval in Log_EM log(cm^-3) stat.error;phys.emissMeasure double nullable log_nh_neg_err Lower 90%-Confidence Interval in Log_NH log(cm^-2) stat.error;phys.columnDensity 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