M 33 Chandra ACIS Survey (ChASeM33) Final Source Catalog

M 33 Chandra ACIS Survey (ChASeM33) Final Source Catalog M33CHASE ivo://nasa.heasarc/m33chase NASA/GSFC HEASARC Tullmann et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the final source catalog of the Chandra ACIS Survey of M33 (ChASeM33). With a total exposure time of 1.4 Ms, ChASeM33 covers ~70% of the D25 isophote (radial extent ~ 4.0 kpc) of M33 and provides the deepest, most complete, and detailed look at a spiral galaxy in X-rays. The source catalog includes 662 sources, reaches a limiting unabsorbed luminosity of ~2.4 x 1034 erg s-1 in the 0.35-8.0 keV energy band, and contains source positions, source net counts, fluxes and significances in several energy bands, and information on source variability. The analysis challenges posed by ChASeM33 and the techniques adopted to address these challenges are discussed. To constrain the nature of the detected X-ray source, hardness ratios were constructed and spectra were fit for 254 sources, follow-up Multiple Mirror Telescope (MMT) spectra of 116 sources were acquired, and cross-correlations with previous X-ray catalogs and other multi-wavelength data were generated. Based on this effort, 183 of the 662 ChASeM33 sources could be identified. Finally, in the reference paper, the luminosity function (LF) for the detected point sources as well as the one for the X-ray binaries (XRBs) in M33 were presented. The LFs in the soft band (0.5-2.0 keV) and the hard band (2.0-8.0 keV) have a limiting luminosity at the 90% completeness limit of 4.0 x 1034 erg s-1 and 1.6 x 1035 erg s-1 (for an assumed distance D to M33 of 817 kpc), respectively, which is significantly lower than what was reported by previous XRB population studies in galaxies more distant than M33. The resulting distribution is consistent with a dominant population of high-mass XRBs as would be expected for M33. The list of all the Chandra ACIS observations that were used in the construction of this source catalog is given in table 2 of the 2011 reference paper. X-ray source properties, such as counts, dns values, and photon fluxes were computed in the following energy bands: <pre> Band Energy Range (keV) 1 0.5 - 8.0 2 0.5 - 2.0 3 2.0 - 8.0 4 0.35- 8.0 5 0.35- 1.1 6 1.1 - 2.6 7 2.6 - 8.0 8 0.35- 2.0 </pre> This table was created by the HEASARC in April 2011 based on electronic versions of Tables 3, 4, 5, 6, 7 and 9 from the 2011 reference paper which were obtained from the ApJS web site. This is a service provided by NASA HEASARC . 2011ApJS..193...31T https://heasarc.gsfc.nasa.gov/W3Browse/all/m33chase.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=m33chase& GET text/xml 180 99999 true 23.512167 30.34517 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=m33chase GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_m33chase&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public m33chase M 33 Chandra ACIS Survey (ChASeM33) Final Source Catalog name 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 b4_counts Total Net Counts in the 0.35-8.0 keV Energy Band ct phot;em.X-ray double nullable b4_counts_pos_err The Upper 90% Confidence Level in B4_Counts ct stat.error;phot;em.X-ray double nullable b4_counts_neg_err The Lower 90% Confidence Level in B4_Counts ct stat.error;phot;em.X-ray double nullable b4_photon_flux Photon Flux in the 0.35-8.0 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable lx The 0.35-8 keV Luminosity erg/s phys.luminosity;em.X-ray double nullable lx_pos_err The Upper 90% Confidence Level in the 0.35-8 keV Luminosity erg/s stat.error;phys.luminosity;em.X-ray double nullable lx_neg_err The Lower 90% Confidence Level in the 0.35-8 keV Luminosity erg/s stat.error;phys.luminosity;em.X-ray double nullable b4_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 0.35-8.0 keV Band meta.code;stat.probability char nullable b2_counts Total Net Counts in the 0.5-2.0 keV Energy Band ct phot;em.X-ray double nullable sb_lx The 0.35-2 keV Luminosity erg/s phys.luminosity;em.X-ray.soft double nullable fit_norm Normalization Constant of the Fit stat.fit.param double nullable other_comments Additional Comment(s) meta.note char nullable b2_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 0.5-2.0 keV Band meta.code;stat.probability char nullable b5_counts_pos_err The Upper 90% Confidence Level in B5_Counts ct stat.error;phot;em.X-ray double nullable b5_counts_neg_err The Lower 90% Confidence Level in B5_Counts ct stat.error;phot;em.X-ray double nullable lt_var_index The 5-Sigma Variability Index meta.code;src.var double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable mph06_source_number MPH06 XMM Source Number short nullable lt_var_flag Flag [b] Indicates Highly Likely to Exhibit Long-Term Variability meta.code;src.var char nullable best_fit_model Best-Fit Model meta.code;meta.modelled char nullable b3_pns Poisson Probability of Not Being a Source in the 2.0-8.0 keV Energy Band stat.probability double nullable b5_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 0.35-1.1 keV Band meta.code;stat.probability char nullable error_radius Positional Error arcsec stat.error;pos double nullable b3_counts_neg_err The Lower 90% Confidence Level in B3_Counts ct stat.error;phot;em.X-ray double nullable b6_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 1.1-2.6 keV Band meta.code;stat.probability char nullable b5_pns Poisson Probability of Not Being a Source in the 0.35-1.1 keV Energy Band stat.probability double nullable exposure Total Exposure in All Observations (s) s time.duration;obs.exposure int nullable apec_kt Plasma Temperature, kT (keV) keV phys.temperature double nullable b8_counts_pos_err The Upper 90% Confidence Level in B8_Counts ct stat.error;phot;em.X-ray double nullable h_alpha_sb H-Alpha Surface Brightness erg/s/cm^2/arcsec^2 phot.flux.sb;em.line.Halpha double nullable b6_counts_neg_err The Lower 90% Confidence Level in B6_Counts ct stat.error;phot;em.X-ray double nullable b1_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 0.5-8.0 keV Band meta.code;stat.probability char nullable off_axis Average Off-Axis Angle (arcmin) arcmin instr.offset double nullable b1_counts_neg_err The Lower 90% Confidence Level in B1_Counts ct stat.error;phot;em.X-ray double nullable fit_dof Degrees of Freedom of the Fit stat.fit.dof short nullable nh_pos_err The Upper 90% Confidence Level in NH cm^-2 stat.error;phys.columnDensity double nullable spectral_index_pos_err The Upper 90% Confidence Level in Gamma stat.error;spect.index double nullable b1_pns Poisson Probability of Not Being a Source in the 0.5-8.0 keV Energy Band stat.probability double nullable b3_counts_pos_err The Upper 90% Confidence Level in B3_Counts ct stat.error;phot;em.X-ray double nullable reduced_chi_squared Reduced Chi^2 of the Fit stat.fit.chi2 double nullable b8_pns Poisson Probability of Not Being a Source in the 0.35-2.0 keV Energy Band stat.probability double nullable ks_prob_constant_limit Limit Flag for KS Probability of a Constant Source meta.code;stat.probability char nullable b8_counts_neg_err The Lower 90% Confidence Level in B8_Counts ct stat.error;phot;em.X-ray double nullable extent_flag Flag Indicates Extended Source Code meta.code;phys.angSize short nullable b2_photon_flux Photon Flux in the 0.5-2.0 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable b7_photon_flux Photon Flux in the 2.6-8.0 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable max_to_min_flux Ratio of Max to Min X-Ray Fluxes phot.flux;arith.ratio double nullable nh Internal Column Density cm^-2 phys.columnDensity double nullable ks_prob_constant_flag Flag [b] Indicates Highly Likely to Exhibit Short-Term Variability meta.code;stat.probability char nullable tot_exposure_map Total Exposure Map Value s.cm^2 meta.number;obs.exposure double nullable b1_counts Total Net Counts in the 0.5-8.0 keV Energy Band ct phot;em.X-ray double nullable b3_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 2.0-8.0 keV Band meta.code;stat.probability char nullable apec_kt_neg_err The Upper 90% Confidence Level in kT keV stat.error;phys.temperature double nullable fit_norm_neg_err The Lower 90% Confidence Level in the Normalization Constant of the Fit stat.error;stat.fit.param double nullable apec_kt_pos_err The Lower 90% Confidence Level in kT keV stat.error;phys.temperature double nullable flc_source_number ChASeM33 First Look Catalog Number meta.id short nullable bck_radius Average Background Radius in Sky Pixels pixel pos.angDistance double nullable b5_counts Total Net Counts in the 0.35-1.1 keV Energy Band ct phot;em.X-ray double nullable b8_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 0.35-2.0 keV Band meta.code;stat.probability char nullable fit_norm_pos_err The Upper 90% Confidence Level in the Normalization Constant of the Fit stat.error;stat.fit.param double nullable b2_counts_neg_err The Lower 90% Confidence Level in B2_Counts ct stat.error;phot;em.X-ray double nullable num_obs Number of Observations short nullable type_and_id_comments Source Type and Comments meta.note char nullable b6_pns Poisson Probability of Not Being a Source in the 1.1-2.6 keV Energy Band stat.probability double nullable b3_photon_flux Photon Flux in the 2.0-8.0 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable b1_photon_flux Photon Flux in the 0.5-8.0 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable spectral_index_neg_err The Lower 90% Confidence Level in Gamma stat.error;spect.index double nullable spectral_index Spectral Index spect.index double nullable sb_lx_pos_err The Upper 90% Confidence Level in the 0.35-2 keV Luminosity erg/s stat.error;phys.luminosity;em.X-ray.soft double nullable b2_pns Poisson Probability of Not Being a Source in the 0.5-2.0 keV Energy Band stat.probability double nullable sb_lx_neg_err The Lower 90% Confidence Level in the 0.35-2 keV Luminosity erg/s stat.error;phys.luminosity;em.X-ray.soft double nullable bii Galactic Latitude degree pos.galactic.lat double nullable b8_photon_flux Photon Flux in the 0.35-2.0 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable g05_source_number G05 Chandra Source Catalog Number short nullable pmh04_source_number PMH04 XMM Source Number short nullable max_to_min_flux_error The 1-Sigma Uncertainty in the Ratio of Max to Min X-Ray Fluxes stat.error;phot.flux;arith.ratio double nullable ks_prob_constant KS Probability of a Constant Source stat.probability double nullable b7_pns Poisson Probability of Not Being a Source in the 2.6-8.0 keV Energy Band stat.probability double nullable b7_counts_neg_err The Lower 90% Confidence Level in B7_Counts ct stat.error;phot;em.X-ray double nullable alt_name Alternative Source Designation meta.id char nullable b6_photon_flux Photon Flux in the 1.1-2.6 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable lii Galactic Longitude degree pos.galactic.lon double nullable nh_neg_err The Lower 90% Confidence Level in NN cm^-2 stat.error;phys.columnDensity double nullable b5_photon_flux Photon Flux in the 0.35-1.1 keV Energy Band photon/cm^2/s phot.flux;em.X-ray double nullable b2_counts_pos_err The Upper 90% Confidence Level in B2_Counts ct stat.error;phot;em.X-ray double nullable b7_counts_pos_err The Upper 90% Confidence Level in B7_Counts ct stat.error;phot;em.X-ray double nullable b7_pns_limit Limit Flag for Poisson Probability of Not Being a Source in 2.6-8.0 keV Band meta.code;stat.probability char nullable b7_counts Total Net Counts in the 2.6-8.0 keV Energy Band ct phot;em.X-ray double nullable b3_counts Total Net Counts in the 2.0-8.0 keV Energy Band ct phot;em.X-ray double nullable b4_pns Poisson Probability of Not Being a Source in the 0.35-8.0 keV Energy Band stat.probability double nullable b8_counts Total Net Counts in the 0.35-2.0 keV Energy Band ct phot;em.X-ray double nullable b6_counts_pos_err The Upper 90% Confidence Level in B6_Counts ct stat.error;phot;em.X-ray double nullable b1_counts_pos_err The Upper 90% Confidence Level in B1_Counts ct stat.error;phot;em.X-ray double nullable source_radius Average Source Radius in Sky Pixels pixel pos.angDistance double nullable b6_counts Total Net Counts in the 1.1-2.6 keV Energy Band ct phot;em.X-ray 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