M 33 Chandra X-Ray Point Source Catalog

M 33 Chandra X-Ray Point Source Catalog ChandraM33 ivo://nasa.heasarc/m33cxoxray NASA/GSFC HEASARC Grimm et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This database table contains a source list for three Chandra observations of the Local Group galaxy M 33. The observations were centered on the nucleus and on the star-forming region NGC 604. A total of 261 sources were detected in an area of about 0.2 square degrees down to a flux limit of 3 x 10-16 erg/s/cm2, which corresponds to a luminosity of ~2 x 1034 erg/s at a distance of 840 kpc. The luminosity functions of the X-ray sources observed in M 33 have been constructed and are consistent with those of other star-forming galaxies, taking into account background contamination. In addition, the combination of X-ray color analysis and the existence of "blue" optical counterparts strongly indicates that the X-ray point source population in M 33 consists of young objects. Above 3 x 1035 erg/s, there are few X-ray sources in the locus of the X-ray hardness ratio diagram that is generally populated by low-mass X-ray binaries. Notice that each of the 261 X-ray sources in the source list has 3 entries in this table, one for each separate Chandra observation, making a total of 783 entries. The Chandra datasets from which this source list was compiled are available by <a href="/db-perl/W3Browse/w3query.pl?tablehead=name%3Dheasarc_chanmaster&sortvar=obsid&bparam_obsid=786%3B+1730%3B+2023">querying CHANMASTER for obsids 786, 1730, and 2023</a>. This table was created by the HEASARC in December 2005 based on the machine-readable version of Table 3 in the above-mentioned Grimm et al. (2005) reference obtained from the ApJ Electronic Edition website. This is a service provided by NASA HEASARC . 2005ApJS..161..271G https://heasarc.gsfc.nasa.gov/W3Browse/all/m33cxoxray.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=m33cxoxray& GET text/xml 180 99999 true 23.60617083 30.47269444 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=m33cxoxray GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_m33cxoxray&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public m33cxoxray M 33 Chandra X-Ray Point Source Catalog name Chandra 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 obsid Chandra Observation Identification Number meta.id;obs short nullable counts_fb_limit Limit Flag for Total (0.3-8.0 keV) Counts char nullable counts_fb Total (0.3-8.0 keV) Counts ct double nullable counts_fb_error 1-Sigma Error in Total (0.3-8.0 keV) Counts ct double nullable flux_fb_error 1-Sigma Error in Total (0.3-8.0 keV) Flux (ct/s/cm^2) ct/s/cm^2 double nullable flux_hb_flag Flag Indicates Most Probable Hard Flux Value char nullable flux_sb_error 1-Sigma Error in Soft (0.3-2.0 keV) Flux (ct/s/cm^2) ct/s/cm^2 double nullable counts_mcb_error 1-Sigma Error in 1.0-2.1 keV Counts ct double nullable flux_sb_limit Limit Flag for Soft (0.3-2.0 keV) Flux char nullable flux_sb_flag Flag Indicates Most Probable Soft Flux Value char nullable source_flag Source Identification Flag Indicates Nucleus char nullable flux_fb_flag Flag Indicates Most Probable Total Flux Value char nullable counts_hb_flag Flag Indicates Most Probable Hard-Band Counts Value char nullable counts_mcb_limit Limit Flag for 1.0-2.1 keV Counts char nullable counts_hb_error 1-Sigma Error in Hard-Band Counts ct double nullable counts_sb_limit Limit Flag for Soft (0.3-2.0 keV) Counts char nullable counts_sb Soft (0.3-2.0 keV) Counts ct double nullable counts_fb_flag Flag Indicates Most Probable Total Counts Value char nullable flux_hb_limit Limit Flag for Total (2.0-8.0 keV) Flux char nullable counts_hb_limit Limit Flag for Hard (2.0-8.0 keV) Counts char nullable lii Galactic Longitude degree pos.galactic.lon double nullable counts_mcb 1.0-2.1 keV Counts ct double nullable flux_hb_error 1-Sigma Error in Total (2.0-8.0 keV) Flux (ct/s/cm^2) ct/s/cm^2 double nullable counts_sb_flag Flag Indicates Most Probable Soft Counts Value char nullable counts_sb_error 1-Sigma Error in Soft (0.3-2.0 keV) Counts ct double nullable flux_hb Total (2.0-8.0 keV) Flux (ct/s/cm^2) ct/s/cm^2 double nullable counts_hcb_limit Limit Flag for 1.0-2.1 keV Counts char nullable counts_scb_error 1-Sigma Error in 0.3-1.0 keV Counts ct double nullable error_radius Positional Uncertainty (arcsec) arcsec stat.error;pos float nullable lx Total (0.3-8.0 kev) Luminosity (erg/s) erg/s double nullable counts_scb 0.3-1.0 keV Counts ct double nullable counts_hcb 2.1-8.0 keV Counts ct double nullable counts_hb Hard (2.0-8.0 keV) Counts ct double nullable counts_scb_limit Limit Flag for 0.3-1.0 keV Counts char nullable flux_fb_limit Limit Flag for Total Flux char nullable flux_fb Total (0.3-8.0 keV) Flux (ct/s/cm^2) ct/s/cm^2 double nullable bii Galactic Latitude degree pos.galactic.lat double nullable counts_hcb_error 1-Sigma Error in 2.1-8.0-keV Counts ct double nullable lx_limit Limit Flag on Total Luminosity char nullable lx_flag Flag Indicates Most Probable Luminosity Value char nullable flux_sb Soft (0.3-2.0 keV) Flux (ct/s/cm^2) ct/s/cm^2 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