XMMOMCAT ivo://nasa.heasarc/xmmomcat NASA/GSFC HEASARC Kuntz et al. 2026-04-03 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Object The Optical Monitor Catalog of serendipitous sources (OMCat) contains entries for every source detected in the publicly available XMM-Newton Optical Monitor (OM) images taken in the imaging mode. Since the OM records data simultaneously with the X-ray telescopes on XMM-Newton, it typically produces images in one or more near-UV/optical bands for every pointing of the observatory. As of the beginning of 2014, the data in the public archive covered roughly 0.5% of the sky in 3425 fields. The OMCat is not dominated by sources previously undetected at other wavelengths; the bulk of objects have optical counterparts. However, the OMCat can be used to extend optical or X-ray spectral energy distributions for known objects into the ultraviolet, to study at higher angular resolution objects detected with GALEX, or to find high-Galactic-latitude objects of interest for UV spectroscopy. Differences between the current OMCat and the previous version of the OMCat (which was designated as XMMOMOBJ) are improved coordinates, improved quality flags, and a reduced number of spurious sources. The OM reduction was done with the standard ESAS software, with post-processing to apply the coordinate corrections in a more consistent manner. There is a major change in the way the data are represented in the table. In the previous XMMOMOBJ table a separate row was generated for each filter. In the current XMMOMCAT table each observation of each object generates only a single row regardless of how many filters were used. Unused filters have nulls while filters where the object is not detected have nulls for the detection parameters but a non-zero value for exposure. The table includes information for each filter and averaged information for the object as a whole. Only filters in which the object was detected are used in the averages. The parameters in this table comprise two sets: parameters describing the detection overall including id's and mean values, and values specific to the individual bands. There are three possible situations for the band data: (1) If there was no exposure in that band, then all fields for that band will be null. (2) If there was some exposure in the band but the object was not detected in that band, then the exposure field will give the actual exposure, but all of the other fields for that band will be null. (3) If the object was detected, then all of the fields for the band should be filled in. The filters included are V, B, U, UVW1, UVM2, UVW2 and white (i.e., unfiltered). The original table (formerly known as XMMOMOBJ) was created by the HEASARC in March 2008, based on a table supplied by the authors. The XMMOMCAT version was generated and ingested in February 2014 using a program which concatenated the objects detected in processing each observation. This is a service provided by NASA HEASARC . 2008PASP..120..740K https://heasarc.gsfc.nasa.gov/W3Browse/all/xmmomcat.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=xmmomcat& GET text/xml 180 99999 true 250.249679866646 -45.6331974209246 0.00416666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=xmmomcat GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_xmmomcat&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.00416666666666667 Optical UV public xmmomcat XMM-Newton OM Object Catalog v_c_flag V-Band Confusion Flag meta.code.multip;em.opt.V short nullable uvm2_mag UVM2-Band Instrumental Magnitude mag phot.mag;em.UV.200-300nm double nullable v_snr V-Band Significance stat.snr;em.opt.V double nullable v_rate_error V-Band Count Rate Uncertainty ct/s stat.error;phot.count;em.opt.V double nullable white_rate_error White-Band Count Rate Uncertainty ct/s stat.error;phot.count double nullable uvw2_mag UVW2-Band Instrumental Magnitude mag phot.mag;em.UV.200-300nm double nullable u_rate_error U-Band Count Rate Uncertainty ct/s stat.error;phot.count;em.opt.U double nullable usno_ra Right Ascension of Matching USNO Object degree pos.eq.ra double nullable "__row" System index column char nullable b_mag B-Band Instrumental Magnitude mag phot.mag;em.opt.B double nullable b_position_angle B-Band Position Angle of Major Axis degree pos.posAng;em.opt.B double nullable b_q_flag B-Band Quality Flag meta.code.qual;em.opt.B short nullable u_major_axis U-Band Major Axis arcsec phys.angSize;em.opt.U double nullable uvw1_mag UVW1-Band Instrumental Magnitude mag phot.mag;em.UV.200-300nm double nullable uvm2_mag_error UVM2-Band Magnitude Uncertainty mag stat.error;phot.mag;em.UV.200-300nm double nullable u_exposure U-Band Exposure Time s time.duration;obs.exposure;em.opt.U double nullable b_snr B-Band Significance stat.snr;em.opt.B double nullable uvm2_position_angle UVM2-Band Position Angle of Major Axis degree pos.posAng;em.UV.200-300nm double nullable b_c_flag B-Band Confusion Flag meta.code.multip;em.opt.B short nullable uvw2_position_angle Position Angle of Major Axis degree pos.posAng;em.UV.200-300nm double nullable source_id Unique Identifier of Object in Catalog meta.id;meta.main char nullable v_rate V-Band Count Rate ct/s phot.count;em.opt.V double nullable uvm2_q_flag UVM2-Band Quality Flag meta.code.qual;em.UV.200-300nm short nullable uvw2_rate_error UVW2-Band Count Rate Uncertainty ct/s stat.error;phot.count;em.UV.200-300nm double nullable error_radius Position Error arcsec stat.error;pos double nullable "__z_ra_dec" System unit vector column double nullable b_minor_axis B-Band Minor Axis arcsec phys.angSize;em.opt.B double nullable white_q_flag White-Band Quality Flag meta.code.qual short nullable u_mag_error U-Band Magnitude Uncertainty mag stat.error;phot.mag;em.opt.U double nullable v_q_flag V-Band Quality Flag meta.code.qual;em.opt.V short nullable uvw1_mag_error UVW1-Band Magnitude Uncertainty mag stat.error;phot.mag;em.UV.200-300nm double nullable uvm2_major_axis UVM2-Band Major Axis arcsec phys.angSize;em.UV.200-300nm double nullable b_exposure B-Band Exposure Time s time.duration;obs.exposure;em.opt.B double nullable u_minor_axis U-Band Minor Axis arcsec phys.angSize;em.opt.U double nullable uvm2_e_flag UVM2-Band Extension Flag meta.code;phys.angSize;em.UV.200-300nm short nullable b_rate_error B-Band Count Rate Uncertainty ct/s stat.error;phot.count;em.opt.B double nullable uvw1_e_flag UVW1-Band Extension Flag meta.code;phys.angSize;em.UV.200-300nm short nullable "__y_ra_dec" System unit vector column double nullable uvw1_q_flag UVW1-Band Quality Flag meta.code.qual;em.UV.200-300nm short nullable b_rate B-Band Count Rate ct/s phot.count;em.opt.B double nullable uvw2_rate UVW2-Band Count Rate ct/s phot.count;em.UV.200-300nm double nullable obsid XMM-Newton Unique Observation Identifier meta.id;obs char nullable v_major_axis V-Band Major Axis arcsec phys.angSize;em.opt.V double nullable white_c_flag White-Band Confusion Flag meta.code.multip short nullable v_mag V-Band Instrumental Magnitude mag phot.mag;em.opt.V double nullable white_rate White-Band Count Rate ct/s phot.count double nullable v_position_angle Position Angle of V-Band Major Axis degree pos.posAng;em.opt.V double nullable white_position_angle White-Band Position Angle of Major Axis degree pos.posAng double nullable uvw1_snr UVW1-Band Significance stat.snr;em.UV.200-300nm double nullable rms_res RMS Residuals in Fit with USNO Catalog arcsec stat.error;pos double nullable u_e_flag U-Band Extension Flag meta.code;phys.angSize;em.opt.U short nullable white_mag_error White-Band Magnitude Uncertainty mag stat.error;phot.mag double nullable uvw2_exposure UVW2-Band Exposure Time s time.duration;obs.exposure;em.UV.200-300nm double nullable b_major_axis B-Band Major Axis arcsec phys.angSize;em.opt.B double nullable ra Right Ascension of Nominal Observation Center degree pos.eq.ra;meta.main double nullable "time" Start Time of the Observation mjd time.start;obs double nullable uvw2_e_flag UVW2-Band Extension Flag meta.code;phys.angSize;em.UV.200-300nm short nullable u_snr U-Band Significance stat.snr;em.opt.U double nullable uvw1_minor_axis UVW1-Band Minor Axis arcsec phys.angSize;em.UV.200-300nm double nullable obj_num Source Number within Observation meta.id;src short nullable uvw1_position_angle UVW1-Band Position Angle of Major Axis degree pos.posAng;em.UV.200-300nm double nullable v_minor_axis V-Band Minor Axis arcsec phys.angSize;em.opt.V double nullable uvw2_minor_axis UVW2-Band Minor Axis arcsec phys.angSize;em.UV.200-300nm double nullable uvw1_c_flag UVW1-Band Confusion Flag meta.code.multip;em.UV.200-300nm short nullable minor_axis Average Value for Minor Axis arcsec phys.angSize double nullable u_mag U-Band Instrumental Magnitude mag phot.mag;em.opt.U double nullable e_flag Combined Extension Flag meta.code;phys.angSize short nullable uvm2_rate_error UVM2-Band Count Rate Uncertainty ct/s stat.error;phot.count;em.UV.200-300nm double nullable lii Galactic Longitude of Nominal Observation Center degree pos.galactic.lon double nullable bii Galactic Latitude of Nominal Observation Center degree pos.galactic.lat double nullable "__x_ra_dec" System unit vector column double nullable uvw2_major_axis UVW2-Band Major Axis arcsec phys.angSize;em.UV.200-300nm double nullable uvw2_q_flag UVW2-Band Quality Flag meta.code.qual;em.UV.200-300nm short nullable uvw1_rate_error UVW1-Band Count Rate Uncertainty ct/s stat.error;phot.count;em.UV.200-300nm double nullable uvm2_rate UVM2-Band Count Rate ct/s phot.count;em.UV.200-300nm double nullable uvw1_rate UVW1-Band Count Rate ct/s phot.count;em.UV.200-300nm double nullable v_exposure V-Band Exposure Time s time.duration;obs.exposure;em.opt.V double nullable usno_dec Declination of Matching USNO Object degree pos.eq.dec double nullable q_flag Combined Quality Flag meta.code.qual short nullable major_axis Average Value for Major Axis arcsec phys.angSize double nullable uvw1_major_axis UVW1-Band Major Axis arcsec phys.angSize;em.UV.200-300nm double nullable uvw2_snr UVW2-Band Significance stat.snr;em.UV.200-300nm double nullable white_minor_axis White-Band Minor Axis arcsec phys.angSize double nullable uvw1_exposure UVW1-Band Exposure Time s time.duration;obs.exposure;em.UV.200-300nm double nullable u_q_flag U-Band Quality Flag meta.code.qual;em.opt.U short nullable u_rate U-Band Count Rate ct/s phot.count;em.opt.U double nullable uvm2_exposure UVM2-Band Exposure Time s time.duration;obs.exposure;em.UV.200-300nm double nullable dec Declination of Nominal Observation Center degree pos.eq.dec;meta.main double nullable u_c_flag U-Band Confusion Flag meta.code.multip;em.opt.U short nullable white_exposure White-Band Exposure Time s time.duration;obs.exposure double nullable white_e_flag White-Band Extension Flag meta.code;phys.angSize short nullable uvw2_mag_error UVW2-Band Magnitude Uncertainty mag stat.error;phot.mag;em.UV.200-300nm double nullable white_major_axis White-Band Major Axis arcsec phys.angSize double nullable position_angle Position Angle of Major Axis degree pos.posAng double nullable white_snr White-Band Significance stat.snr double nullable v_e_flag V-Band Extension Flag meta.code;phys.angSize;em.opt.V short nullable u_position_angle U-Band Position Angle of Major Axis degree pos.posAng;em.opt.U double nullable uvm2_minor_axis UVM2-Band Minor Axis arcsec phys.angSize;em.UV.200-300nm double nullable c_flag Combined Confusion Flag meta.code.multip short nullable uvm2_snr UVM2-Band Significance stat.snr;em.UV.200-300nm double nullable uvw2_c_flag UVW2-Band Confusion Flag meta.code.multip;em.UV.200-300nm short nullable b_mag_error B-Band Magnitude Uncertainty mag stat.error;phot.mag;em.opt.B double nullable v_mag_error V-Band Magnitude Uncertainty mag stat.error;phot.mag;em.opt.V double nullable b_e_flag B-Band Extension Flag meta.code;phys.angSize;em.opt.B short nullable white_mag White-Band Instrumental Magnitude mag phot.mag double nullable uvm2_c_flag UVM2-Band Confusion Flag meta.code.multip;em.UV.200-300nm short nullable