ELAISS1OID ivo://nasa.heasarc/elaiss1oid NASA/GSFC HEASARC Feruglio et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the optical identifications and a multi-band catalog of a sample of 478 X-ray sources detected in the XMM-Newton and Chandra surveys of the central 0.6 deg<sup>2</sup> of the ELAIS-S1 field. The most likely optical/infrared counterpart of each X-ray source was identified using the chance coincidence probability in the R and IRAC 3.6 micron bands.This method was complemented by the precise positions obtained through Chandra observations. The authors were able to associate a counterpart to each X-ray source in the catalogue. Approximately 94% of them are detected in the R band, while the remaining are blank fields in the optical down to R ~ 24.5, but have a near-infrared counterpart detected by IRAC within 6 arcsec of the XMM-Newton centroid. The multi-band catalog, produced using the positions of the identified optical counterparts, contains photometry in ten photometric bands, from B to the MIPS 24 micron band. The spectroscopic follow-up allowed us to determine the redshift and classification for 237 sources (~ 50% of the sample) brighter than R = 24. The spectroscopic redshifts were complemented by reliable photometric redshifts for 68 sources. The authors classified 47% of the sources with spectroscopic redshift as broad-line active galactic nuclei (BL AGNs) with z = 0.1-3.5, while sources without broad-lines (NOT BL AGNs) are about 46% of the spectroscopic sample and are found up to z = 2.6. The remaining fraction is represented by extended X-ray sources and stars. The authors spectroscopically identified 11 type 2 QSOs among the sources with F(2-10 keV)/F(R) > 8, with redshift between 0.9 and 2.6, high 2-10 keV luminosity (log L(2-10 keV) >= 43.8 erg/s) and hard X-ray colors suggesting large absorbing columns at the rest frame (log N<sub>H</sub> up to 23.6 cm<sup>-2</sup>). BL AGNs show on average blue optical-to-near-infrared colors, softer X-ray colors and X-ray-to-optical colors typical of optically selected AGNs. Conversely, narrow-line sources show redder optical colors, harder X-ray flux ratio and span a wider range of X-ray-to-optical colors. On average the Spectral Energy Distributions (SEDs) of high-luminosity BL AGNs resemble the power-law typical of unobscured AGNs. The SEDs of NOT BLAGNs are dominated by the galaxy emission in the optical/near-infrared, and show a rise in the mid-infrared which suggests the presence of an obscured active nucleus. The authors have used the infrared-to-optical colors and near-infrared SEDs to infer the properties of the AGN host galaxies. Identifications and photometric parameters for 478 sources detected by XMM-Newton in the ELAIS-S1 field are given. For each source, the X-ray positions and fluxes, optical position and photometry, Spitzer IRAC and MIPS 24 micron positions and fluxes, spectroscopic redshift where available, photometric redshift and SED shape classification are given. This table was created by the HEASARC in December 2008 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/488/417">CDS Catalog J/A+A/488/417</a> file catalog.dat. This is a service provided by NASA HEASARC . 2008A&A...488..417F https://heasarc.gsfc.nasa.gov/W3Browse/all/elaiss1oid.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=elaiss1oid& GET text/xml 180 99999 true 8.83962 -43.92045 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=elaiss1oid GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_elaiss1oid&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.0166666666666667 Infrared Optical X-ray public elaiss1oid ELAIS S1 Field X-Ray Source Optical/IR Identifications 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 flux Flux 0.5-10keV (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray double nullable flux_error Error on Flux 0.5-10keV (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray double nullable vmag V Band Magnitude (VEGA) from ESIS Catalog mag phot.mag;em.opt.V double nullable rmag R Band Magnitude (VEGA) from ESIS Catalog mag phot.mag;em.opt.R double nullable flux_3p6_um IRAC 3.6um Flux (uJy) microJy phot.flux.density;em.IR.3-4um double nullable flux_3p6_um_error IRAC 3.6um Flux Error (uJy) microJy stat.error;phot.flux.density;em.IR.3-4um double nullable esis_ra Right Ascension in ESIS Catalog degree double nullable jmag_best J-Band Magnitude (VEGA) mag phot.mag;em.IR.J double nullable sb_flux Flux 0.5-2keV Band (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray.soft double nullable flux_24_um_error MIPS 24um Flux Error (uJy) microJy stat.error;phot.flux.density;em.IR.15-30um double nullable bmag_limit Limit Flag for B Magnitude meta.code;phot.mag;em.opt.B char nullable kmag_limit Limit Flag for K Magnitude meta.code;phot.mag;em.IR.K char nullable redshift_flag Redshift Quality Flag meta.code.qual;src.redshift double nullable rmag_flags Flags for R Band meta.code short nullable sb_snr Signal-to-Noise Ratio in 0.5-2keV Band stat.snr;phot.flux;em.X-ray.soft double nullable instrument_code Instrument Code meta.code;instr short nullable irac_dec IRAC Declination degree double nullable lii Galactic Longitude degree pos.galactic.lon double nullable spectrum_id FORS2/VLT Spectrum ID for the Optical Counterpart meta.code short nullable kmag_error K Magnitude Error mag stat.error;phot.mag;em.IR.K double nullable bmag_error B Magnitude Error mag stat.error;phot.mag;em.opt.B double nullable chandra_dec Chandra Declination degree double nullable spectrum_code FORS2/VLT Spectrum Code for the Optical Counterpart meta.code int nullable irac_serendip_flag Chance Coincidence Probability (3.6 micron) meta.code double nullable esis_source_number Source Number in ESIS Catalog meta.id.cross int nullable chandra_ra Chandra Right Ascension degree double nullable rmag_error R Magnitude Error mag stat.error;phot.mag;em.opt.R double nullable vimos_dec VIMOS/VLT Declination degree double nullable rmag_serendip_flag Chance Coincidence Probability (R Band) meta.code double nullable chandra_covered Flag [1] Indicates Area Is Covered by Chandra Observations meta.code short nullable jmag_dec J-Band Declination degree double nullable rmag_ellipticity Ellipticity in R Band src.ellipticity double nullable jmag_best_error J Magnitude Error mag stat.error;phot.mag;em.IR.J double nullable snr Signal-to-Noise Ratio in 0.5-10keV Band stat.snr;phot.flux;em.X-ray double nullable photometry_flag Photometry from 2.2=ESO/WFI, 8.0=VIMOS/VLT meta.code double nullable flux_24_um MIPS 24um Flux (uJy) microJy phot.flux.density;em.IR.15-30um double nullable hb_flux Flux 2-10keV Band (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray.medium double nullable rmag_best_error Error in R-Band BEST Magnitude mag stat.error;phot.mag;em.opt.R double nullable uhb_flux Flux 5-10 keV Band (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray.medium double nullable class Browse Object Classification src.class short nullable hb_snr Signal-to-Noise Ratio in 2-10keV Band stat.snr;phot.flux;em.X-ray.medium double nullable hb_flux_error Error on Flux 2-10keV (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable vmag_error V Magnitude Error mag stat.error;phot.mag;em.opt.V double nullable kmag_ellipticity Ellipticity in K Band src.ellipticity double nullable bmag B Band Magnitude (VEGA) from ESIS Catalog mag phot.mag;em.opt.B double nullable broad_type Broad Classification [1-6] src.class short nullable esis_dec Declination in ESIS Catalog degree double nullable xmm_irac_offset X-Ray to IRAC Position Offset (arcsec) arcsec pos.angDistance;em.X-ray;em.IR double nullable kmag_flags Flags for K Band meta.code short nullable swire_source_number Swire IRAC ID meta.id.cross int nullable flux_4p5_um IRAC 4.5um Flux (uJy) microJy phot.flux.density;em.IR.4-8um double nullable redshift Spectroscopic Redshift of the Optical Counterpart src.redshift double nullable bii Galactic Latitude degree pos.galactic.lat double nullable photo_redshift_chi2 Chi-Squared for Photometric Redshift Fit of Counterpart to X-Ray Source stat.fit.chi2;src.redshift.phot double nullable kmag_galaxy_flag Star/Galaxy Separation in K Band (0 for Galaxy) meta.code double nullable rmag_best R-Band BEST Magnitude (VEGA) from VIMOS mag phot.mag;em.opt.R double nullable photo_redshift Best-Fit Photometric Redshift src.redshift.phot double nullable flux_5p8_um_error IRAC 5.8um Flux Error (uJy) microJy stat.error;phot.flux.density;em.IR.4-8um double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable irac_ra IRAC Right Ascension degree double nullable vimos_ra VIMOS/VLT Right Ascension degree double nullable xmm_opt_offset X-Ray to Optical Position Offset (arcsec) arcsec pos.angDistance;em.X-ray;em.opt double nullable sed_classification Optical Spectral Energy Distribution (SED) Classification meta.code.class;src.class short nullable uhb_snr Signal-to-Noise Ratio in 5-10keV Band stat.snr;phot.flux;em.X-ray.medium double nullable kmag K Band Magnitude (VEGA) mag phot.mag;em.IR.K double nullable rmag_limit Limit Flag for R Magnitude meta.code;phot.mag;em.opt.R char nullable sb_flux_error Error on Flux 0.5-2keV (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.soft double nullable flux_8p0_um IRAC 8.0um Flux (uJy) microJy phot.flux.density;em.IR.8-15um double nullable flux_5p8_um IRAC 5.8um Flux (uJy) microJy phot.flux.density;em.IR.4-8um double nullable chandra_source_number Chandra Source Number meta.id.cross short nullable flux_4p5_um_error IRAC 4.5um Flux Error (uJy) microJy stat.error;phot.flux.density;em.IR.4-8um double nullable flux_8p0_um_error IRAC 8.0um Flux Error (uJy) microJy stat.error;phot.flux.density;em.IR.8-15um double nullable uhb_flux_error Error on Flux 5-10keV (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable jmag_ra J-Band Right Ascension degree double nullable vmag_limit Limit Flag for V Magnitude meta.code;phot.mag;em.opt.V char nullable rmag_best_limit Limit Flag for R Magnitude BEST meta.code;phot.mag;em.opt.R char nullable rmag_galaxy_flag Star/Galaxy Separation in R Band (0 for galaxy) meta.code 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