J/A+AS/127/145 Hamburg/RASS Cat. of optical identifications (HRC) (Bade+, 1998) ================================================================================ The Hamburg/RASS Catalogue of optical identifications. Bade N., Engels D., Voges W., Beckmann V., Boller T., Cordis L., Dahlem M., Englhauser J., Molthagen K., Nass P., Studt J., Reimers D. =1998A&AS..127..145B (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: X-ray sources ; Galaxy catalogs ; QSOs ; Cross identifications Keywords: X-ray sources: general - galaxies - stars Abstract: We present the Hamburg/RASS Catalogue of optical identifications (HRC). The catalogue contains optical information about objects inside the error circles of ROSAT All-Sky Survey (RASS, Cat. ) sources. The information was gathered from objective prism and direct plates taken by the Hamburg Quasar Survey (HQS). The plates enable an effective selection of several X-ray emitting classes of objects, as there are galaxies, AGN, QSOs, galaxy clusters and several types of galactic stars, in particular M dwarfs, hot white dwarfs and cataclysmic variables. In the current state (November 1996) the HRC contains information about 3847 X-ray positions and covers about 8480deg^2^ of the high galactic latitude (|b|>20{deg}) northern sky. For 81.2% of the X-ray sources a plausible optical counterpart is given. The counterparts of the remaining sources are probably faint (B>18.5) AGN and galaxy clusters. The HRC is available electronically together with finding charts taken from the digitized direct HQS plates. Description: The file rassid2.cat provides information on optical identifications to X-ray positions of the ROSAT All-Sky Survey (RASS). The file was created by correlating the Bright Source Catalogue of ROSAT (Voges et al., 1996, Cat. ) and the Hamburg/RASS Catalogue of Optical Identifications (HRC) (Bade et al., 1996, in prep.). In the current state (Version 2.0) the catalogue contains 4665 positions in the extragalactic northern sky. For each X-ray position optical information taken from HQS objective prism and direct Schmidt plates (Hagen et al., 1995A&AS..111..195H) is given and a finding chart derived from digitized direct plates as gzipped Postscript file is provided (sky.ps file). If possible, the most likely optical counterpart is marked in the catalogue and on the finding chart. For many of the newly processed HQS fields of Version 2.0 no direct Schmidt plates from the HQS exists. In these cases we put finding charts generated from the STScI Digitized Sky Survey on the ftp server, ftp.hs.uni-hamburg.de, pub/outgoing/rass-id. We remind the reader that the STScI Digitized Sky Survey and HQS prism plates have different epochs. This has to be taken into account for stellar identifications. Furthermore the spectral sensitivity of the STScI Digitized Sky Survey and the HQS prism plates is different. The finding chart for each X-ray position is stored as a gzipped Postscript file and they can be found in the directories d-10 to d+80 at ftp.hs.uni-hamburg.de, pub/outgoing/rass-id. These directories arrange the files into declination belts. Names of finding charts generated by the STScI Digitized Sky Survey begin with a 'p'. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file rassid1.dat 63 3846 X-ray data (V1.1, issued December 5, 1996, Version of 09/03/2001) optical1.dat 91 8306 Possible optical counterpart to X-ray sources of radio.dat rassid2.dat 63 4664 X-ray data (V2.0, issued January 5, 1998, Version of 09/03/2001) optical2.dat 79 10528 Possible optical counterpart to X-ray sources of radio2.dat sky.ps 93 31559 RASS II identifications based on Schmitd plates -------------------------------------------------------------------------------- See also: J/A+A/406/535 : HRC, V3.0 (Zickgraf+, 2003) IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999) IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000) J/A+AS/115/235 : The Hamburg/ESO survey for bright QSOs. II. (Reimers+, 1996) J/A+A/358/77 : The Hamburg/ESO survey for bright QSOs. III (Wisotzki+, 2000) J/A+AS/128/507 : The Hamburg Quasar Survey. II. (Engels+ 1998) J/A+AS/134/483 : The Hamburg Quasar Survey. III. (Hagen+ 1999) Byte-by-byte Description of file: rassid[12].dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 15 A15 --- RXJ Object name 17- 18 I2 h RAh Right ascension (2000.0) 20- 21 I2 min RAm Right ascension (2000.0) 23- 26 F4.1 s RAs Right ascension (2000.0) 28 A1 --- DE- Declination sign (2000.0) 29- 30 I2 deg DEd Declination (2000.0) 32- 33 I2 arcmin DEm Declination (2000.0) 35- 36 I2 arcsec DES Declination (2000.0) 38- 40 I3 arcsec eRad Error radius derived from the BSC 42- 48 A7 --- Seq Internal number 50- 52 I3 --- IdCode Identification code (1) 54 I1 --- Flag1 [0/1] flag, if set to 1, identification changed since last catalogue version 55 I1 --- Flag2 [0/1] flag, if set to 1, entries to this X-ray position have changed since last catalogue version, 56 I1 --- Flag3 [0/1] flag, supplementary X-ray positions are flagged with 1 58- 63 I6 "YYMMDD" Date Date of last change (YYMMDD) -------------------------------------------------------------------------------- Note (1): The identification code is defined as follows: The first (and third) digit give(s) the classification: 1 : AGN 2 : Galaxy, derived from the morphology on the direct plates 3 : Cluster 5 : M dwarf 6 : White Dwarf 7_1 : K Dwarf 7_2 : F or G star 7_3 : Cataclysmic Variable (CV) 7_4 : Bright Star (B < 13) 8 : no plausible candidate found 803 : one object in favourable position, but no spectral information 0 : empty field on objective prism and direct plate within a radius of at least 40 arcsec The second digit in the identification code describes the reliability of the given identification: 0: 'highly probable', the proposed counterpart fulfills all requirements of its class and no other plausible counterpart within the error radius of the X-ray source exists 1: 'probable', the proposed counterpart fulfills the requirements of its class, but there are limitations. Either, the objective spectrum is not typical, or there are small conflicts with the X-ray information (spectral or spatial information, distance to the X-ray position) or there is another (considerably less) plausible counterpart in the error circle 2: 'possible', the proposed counterpart fulfills some requirements of its class, but there are doubts arising from insufficient objective prism data, conflicting X-ray data or another plausible candidate -------------------------------------------------------------------------------- Byte-by-byte Description of file: optical[12].dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 15 A15 --- RXJ Source name 17 A1 --- Opt [+] +: Proposed optical counterpart 18- 20 I3 --- Seq Possible optical counterpart sequential number 21 A1 --- n_Seq [P] 24- 25 I2 h RAh ? Right ascension (2000.0) 27- 28 I2 min RAm ? Right ascension (2000.0) 30- 33 F4.1 s RAs ? Right ascension (2000.0) 35 A1 --- DE- Declination sign (2000.0) 36- 37 I2 deg DEd ? Declination (2000.0) 39- 40 I2 arcmin DEm ? Declination (2000.0) 42- 43 I2 arcsec DEs [0/60]? Declination (2000.0) 46- 49 I4 arcsec DRA ? X-ray position - optical position in right ascension 51- 54 I4 arcsec DDE ? X-ray position - optical position in declination 56- 58 I3 arcsec DDist ? Distance between X-ray and optical position 60 A1 --- l_Bmag Limit flag on Bmag (1) 61- 64 F4.1 mag Bmag ? Optical magnitude B (2) 65 A1 --- n_Bmag [e:] 67- 69 I3 ---- Code ? Code not defined in the original data 71- 79 A9 --- Class Classification for objective prism spectrum (3) -------------------------------------------------------------------------------- Note (1): a '<' means upper limit for magnitude, the object is saturated Note (2): '>19.0' in column 59-63 means, that the optical counterpart is only visible on the direct plate not on the prism plate(s) no entry means no B magnitude available Note (3): For the classification of objective prism spectra the following scheme was adopted: SUBDWARF: Hot Subdwarfs (sdO,sdB) W-DWARF : White Dwarfs STAR-BA : Balmer absorption lines, point-like image STAR-FG : G-Band, Ca H+K, point-like image STAR-K : G-Band, Ca H+K, redder continuum, point-like image STAR-M : Very red, TiO lines, Ca I 4226, point-like image CV : Cataclysmic variable, Balmer emission lines GALAXY : Extended image on direct plate, no emission lines, red continuum AGN : Emission line(s), blue continuum, weak extension on direct plate allowed BLUE GAL: moderately blue continuum, extended image on direct plate QSO : Emission line(s), extremely blue continuum, : no extension on direct plate EBL-WK : Extremely blue continuum, weak point-like object BLUE-WK : Moderately blue continuum, weak point-like object RED-WK : Red continuum, weak point-like object UNIDENT : Classification open OVERLAP : Classification not possible due to overlapping spectra SATURATE: Classification not possible due to amplifier saturation -------------------------------------------------------------------------------- History: Copied at ftp.hs.uni-hamburg.de, pub/outgoing/rass-id, on 09-Mar-2001 ================================================================================ (End) Patricia Bauer [CDS] 09-Mar-2001