CYDER ivo://nasa.heasarc/cyder NASA/GSFC HEASARC Treister et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The main goal of the Calan-Yale Deep Extragalactic Research (CYDER) Survey X-ray survey is to study serendipitous X-ray sources detected by Chandra in an intermediate flux range (10<sup>-15</sup> to 10<sup>-12</sup> ergs/s) that comprises most of the X-ray background. A total of 267 X-ray sources spread over five archived fields were detected. The log N - log S distribution obtained for this sample is consistent with the results of other surveys. Deep V and I images were taken of these fields in order to calculate X-ray-to-optical flux ratios. Identifications and redshifts were obtained for 106 sources using optical spectroscopy from 8 m class telescopes to reach the optically faintest sources, to the same level as deeper X-ray fields like the Chandra Deep Fields, showing that the nature of sources detected depends mostly on the optical limit for spectroscopy. This table was created by the HEASARC in March 2007 based on the CDS table J/ApJ/621/104, file table4.dat. This is a service provided by NASA HEASARC . 2005ApJ...621..104T https://heasarc.gsfc.nasa.gov/W3Browse/all/cyder.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=cyder& GET text/xml 180 99999 true 330.44479167 -32.10686111 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=cyder GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_cyder&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public cyder Calan-Yale Deep Extragalactic Research Survey X-Ray Source Catal name IAU-Registered Catalog Source Designation (CXOCY JHHMMSS.s+DDMMSS) 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 sb_flux Soft-Band (0.5-2keV) Flux (erg/s/cm^2) erg/s/cm^2 double nullable hb_flux Hard-Band (2.0-8keV) Flux (erg/s/cm^2) erg/s/cm^2 double nullable redshift Redshift src.redshift double nullable sb_lx Soft-Band (0.5-2keV) Luminosity (erg/s) erg/s double nullable hb_lx Hard-Band (2.0-8keV) Luminosity (erg/s) erg/s double nullable vmag_limit Upper Limit Flag for V Magnitude char nullable imag_limit Upper Limit Flag for I Magnitude char nullable bii Galactic Latitude degree pos.galactic.lat double nullable hb_counts Hard-Band (2.0-8keV) Counts ct double nullable source_type Source Class src.class char nullable sb_counts_error Error in Soft-Band Counts ct double nullable sb_counts Soft-Band (0.5-2keV) Counts ct double nullable imag CTIO I Band Magnitude mag phot.mag;em.opt.I double nullable hb_counts_error Error in Hard-Band Counts ct double nullable hardness_ratio Hardness Ratio phot.flux;arith.ratio;em.X-ray.medium;em.X-ray.soft double nullable class Browse Object Classification src.class short nullable lii Galactic Longitude degree pos.galactic.lon double nullable vmag CTIO V Band Magnitude mag phot.mag;em.opt.V 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 off_set X-ray/Optical Positional Offset (arcsec) arcsec instr.offset double nullable