The Hamburg/RASS Catalogue of optical identifications

Bade, N.; Engels, D.; Voges, W.; Beckmann, V.; Boller, Th.; Cordis, L.; Dahlem, M.; Englhauser, J.; Molthagen, K.; Nass, P.; Studt, J.; Reimers, D.

doi:10.1051/aas:1998339

Cited by 120 publications

(120 citation statements)

References 5 publications

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“…One major goal of such surveys is that the radio/X-ray detections should be associated with optical objects to further their classification and to find new examples of emission phenomena. Previous such efforts generally treat just one radio/X-ray survey per paper, and use matching criteria particular to that paper; see notably APM Optical Counterparts to FIRST Radio Sources (MWHB: McMahon et al 2002) and the Hamburg/RASS Catalogue of Optical Identifications (HRC: Bade et al 1998) which has multiple optical identifications per X-ray detection. It is desirable for there to be a single unified catalogue which combines and overlays all these good-resolution radio/X-ray surveys onto the optical background using a uniform optimized matching algorithm.…”

Section: Introductionmentioning

confidence: 99%

An all-sky optical catalogue of radio/X-ray sources

Flesch¹,

Hardcastle

2004

A&A

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Abstract.We present an all-sky catalogue that aligns and overlays the ROSAT HRI, RASS, PSPC and WGA X-ray catalogues and the NVSS, FIRST and SUMSS radio catalogues onto the optical APM and USNO-A catalogues. Objects presented are those APM/USNO-A optical objects which are calculated with ≥40% confidence to be associated with radio/X-ray detections, or which are identified as known QSOs, AGN or BL Lacs, totalling 501 761 objects in all, including 48 285 QSOs and 21 498 double radio lobe detections. For each radio/X-ray associated optical object we display the calculated percentage probabilities of its being a QSO, galaxy, star, or erroneous radio/X-ray association, plus any identification from the literature. The catalogue includes 86 009 objects which were not previously identified and which we list as being 40% to >99% likely to be a QSO. As a byproduct of the construction of this catalogue, we are able to list comprehensive ROSAT field shifts as determined by our whole-sky likelihood algorithm, and also plate-by-plate photometric recalibration of the complete APM and USNO-A2.0 optical catalogues, significantly improving accuracy for objects of >15 mag. The catalogue is available wholly and in subsets at http://quasars.org/qorg-data.htm

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Section: Introductionmentioning

confidence: 99%

An all-sky optical catalogue of radio/X-ray sources

Flesch¹,

Hardcastle

2004

A&A

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“…Within 1 ′ , we found 50 coincidences: 21 QSOs, 22 stars and seven unidentified objects listed in Table 2; recently, one of these objects (FBS 0950+664) has been identified on objective prism plates as an AGN [14].…”

Section: Comparison With X-ray Infrared and Radio Surveysmentioning

confidence: 81%

On the nature of the FBS blue stellar objects and the completeness of the Bright Quasar Survey

et al. 1999

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The second part of the First Byurakan Survey is aimed at detecting all bright (B < 16.5) UV-excess starlike objects in a large area of the sky. By comparison with other major surveys such as the ROSAT All Sky Survey, the ROSAT WGACAT catalogue of point sources, the IRAS survey, the 6 cm Green Bank, the 1.4 GHz NRAO VLA and the 92 cm Westerbork Northern sky surveys and with the catalogue of mean U BV data on stars, we estimate the number of AGNs present in the FBS survey and its completeness.We have made spectroscopic observations of nine of the most promising FBS candidates. We have found six new QSOs bringing the total number of known QSOs in this survey to 42.By comparison with the Bright Quasar Survey, we found that the completeness of this last survey is of the order of 70% rather than 30-50% as suggested by several authors.

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“…Column 7: spectral type. FG means F or G star according to the objective prism spectra taken with the Hamburg Schmidt telescope on Calar Alto (Bade et al 1998). Columns 8-10: RBV magnitudes; if existing, mostly from the USNO-A2 catalogue.…”

Section: Optical Variabilitymentioning

confidence: 99%

“…62d is a galaxy (NGP9 F378-0239941) at z = 0.133 (Gliozzi et al 1999) which coincides with the radio source FIRST J123437.1+235016, thus probably also is an AGN. 62e is a quasar at previously unknown redshift (Bade et al 1998), for which the SDSS-III spectrum provides z = 0.1382 together with a classification as broadline QSO. Based on the X-ray variability, the hardness ratio and f X / f opt we identify 62e as the counterpart.…”

Section: Sdss Spectramentioning

confidence: 99%

Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes

Greiner

Richter

2015

A&A

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Context. The optical identification of large number of X-ray sources such as those from the ROSAT All-Sky Survey is challenging with conventional spectroscopic follow-up observations. Aims. We investigate two ROSAT All-Sky Survey fields of size 10 • × 10 • each, one at galactic latitude b = 83 • (26 Com), the other at b = −5 • (γ Sge), in order to optically identify the majority of sources. Methods. We used optical variability, among other more standard methods, as a means of identifying a large number of ROSAT All-Sky Survey sources. All objects fainter than about 12 mag and brighter than about 17 mag, in or near the error circle of the ROSAT positions, were tested for optical variability on hundreds of archival plates of the Sonneberg field patrol.Results. The present paper contains probable optical identifications of altogether 256 of the 370 ROSAT sources analysed. In particular, we found 126 active galactic nuclei (some of them may be misclassified cataclysmic variables, CVs), 17 likely clusters of galaxies, 16 eruptive double stars (mostly CVs), 43 chromospherically active stars, 65 stars brighter than about 13 mag, 7 UV Cet stars, 3 semiregular resp. slow irregular variable stars of late spectral type, 2 DA white dwarfs, 1 Am star, 1 supernova remnant and 1 planetary nebula. As expected, nearly all active galactic nuclei are found in the high-galactic latitude field, while the majority of CVs is located at low galactic latitudes. We identify in total 72 new variable objects. Conclusions. X-ray emission is, expectedly, tightly correlated with optical variability, and thus our new method for optically identifying X-ray sources is demonstrated to be feasible. Given the large number of optical plates used, this method was most likely not more efficient than e.g. optical spectroscopy. However, it required no telescope time, only access to archival data.

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The Hamburg/RASS Catalogue of optical identifications

Cited by 120 publications

References 5 publications

An all-sky optical catalogue of radio/X-ray sources

An all-sky optical catalogue of radio/X-ray sources

On the nature of the FBS blue stellar objects and the completeness of the Bright Quasar Survey

Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes

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