Optically bright active galactic nuclei in the ROSAT-Faint  source catalogue

Véron-Cetty, M. P.; Balayan, S. K.; Mickaelian, A. M.; Mújica, R.; Chavushyan, V.; Hakopian, S. A.; Engels, D.; Véron, Philippe; Zickgraf, F. J.; Voges, W.; Xu, Da

doi:10.1051/0004-6361:20031686

Cited by 12 publications

(8 citation statements)

References 33 publications

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“… References: 25 –Brand et al (2006); 26 –Aslan et al (2010); 27 – XMM–Newton Survey Science Centre 2008; 28 –Véron‐Cetty et al (2004); 29 –Cappelluti et al (2009). …”

Section: The Cataloguementioning

confidence: 99%

A photometric catalogue of quasars and other point sources in the Sloan Digital Sky Survey

Abraham¹,

Philip²,

Kembhavi³

et al. 2011

Monthly Notices of the Royal Astronomical Society

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We present a catalogue of about six million unresolved photometric detections in the Sloan Digital Sky Survey (SDSS) Seventh Data Release, classifying them into stars, galaxies and quasars. We use a machine learning classifier trained on a subset of spectroscopically confirmed objects from 14th to 22nd magnitude in the SDSS i band. Our catalogue consists of 2 430 625 quasars, 3 544 036 stars and 63 586 unresolved galaxies from 14th to 24th magnitude in the SDSS i band. Our algorithm recovers 99.96 per cent of spectroscopically confirmed quasars and 99.51 per cent of stars to i ∼ 21.3 in the colour window that we study. The level of contamination due to data artefacts for objects beyond i = 21.3 is highly uncertain and all mention of completeness and contamination in the paper are valid only for objects brighter than this magnitude. However, a comparison of the predicted number of quasars with the theoretical number counts shows reasonable agreement.

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“… References: 25 –Brand et al (2006); 26 –Aslan et al (2010); 27 – XMM–Newton Survey Science Centre 2008; 28 –Véron‐Cetty et al (2004); 29 –Cappelluti et al (2009). …”

Section: The Cataloguementioning

confidence: 99%

A photometric catalogue of quasars and other point sources in the Sloan Digital Sky Survey

Abraham¹,

Philip²,

Kembhavi³

et al. 2011

Monthly Notices of the Royal Astronomical Society

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“…Of these sources 683 had been included in the identification program of Véron-Cetty et al (2004). They have optical counterparts brighter than O = 16.5 in USNO-A2.0.…”

Section: The Sample Of Rosat Fsc Sourcesmentioning

confidence: 99%

“…A search for bright optical counterparts (O < 16.5 m ) of X-ray sources of the ROSAT FSC was made by Véron-Cetty et al (2004) by crosscorrelating the FSC with the USNO-A2.0 (Monet et al 1996) and with MAPS (Cabanela et al 2003), and subsequent classification of the candidates with the low-dispersion HQS spectra. Their goal was to obtain a large, optically bright, X-ray selected AGN sample.…”

Section: Introductionmentioning

confidence: 99%

Optical identification of ROSAT-FSC sources

Mickaelian¹,

Hovhannisyan²,

Engels

et al. 2006

A&A

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The Byurakan/Hamburg/ROSAT Catalogue (BHRC) of the optical identifications of X-ray sources is presented. The BHRC includes all 2791 sources from the ROSAT-FSC with |b| ≥ 30• , δ ≥ 0 • and ROSAT count rate CR > 0.04 cts s −1 . For the optical identifications, we used the Hamburg Quasar Survey (HQS) digitized spectroscopic plates, the DSS1 and DSS2 (blue, red, and IR) images, the MAPS photometric data, the USNO-B1.0 (for proper motions), the NVSS and FIRST radio, and the IRAS and 2MASS infrared catalogues. From the DSS images we obtained positional, brightness, color, extension, variability, proper motion information, and measured the optical-to-X-ray distance. Based on the DSS images, a morphological classification was made. Available SIMBAD and NED data were used as well. Cross-correlations were made with AGN, white dwarf, and cataclysmic variable catalogues (322/8/7 associations, respectively). We managed to identify 97% of sources (2696 sources) that are associated with 3202 optical objects. 2248 X-ray sources have a single optical counterpart, 144 have a double or multiple optical counterpart (binaries, galaxy groups etc.), and 304 have ambiguous identifications. We find that some of the latest might actually be blends of two X-ray sources that were not resolved by ROSAT. The QSOs and AGN represent the largest group of X-ray counterparts (56.2%); bright stars (including late type stars, but excluding WDs and CVs) are counterparts for 33.2% of sources, and the bright galaxies and groups of galaxies comprise 9.2%. We found a number of close galaxy pairs (possibly interacting/merging galaxies) that are counterparts for X-ray sources (3.0%), as well as 1.0% WDs and 0.4% CVs. The BHRC may be used for selection and for studies of samples of various classes of X-ray emitters.

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“…Two large works on optical identifications of ROSAT sources were carried out, using ROSAT BSC and FSC (Véron-Cetty et al 2004;Mickaelian et al 2006). A collaboration between Armenian (BAO), French (OHP), Hamburg quasar survey (HQS) and ROSAT teams with participation of scientists from Mexico and China was conducted to study the Hamburg-ROSAT identifications and to select NLS1 galaxies for further detailed investigation.…”

Section: Rosat Sources and Hrc/bhrc Extragalactic Samplementioning

confidence: 99%

Multi-wavelength studies of the statistical properties of active galaxies using Big Data

et al. 2016

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Statistical studies of active galaxies (both AGN and Starburst) using large multiwavelength data are presented, including new studies of Markarian galaxies, large sample of IR galaxies, variable radio sources, and large homogeneous sample of X-ray selected AGN. Markarian survey (the First Byurakan Survey) was digitized and the DFBS database was created, as the biggest spectroscopic database by the number of objects involved (∼20 million). This database provides both 2D images and 1D spectra. We have carried out a number of projects aimed at revealing and multi-wavelength studies of active galaxies among optical, X-ray, IR and radio sources. Thousands of X-ray sources were identified from ROSAT, including many AGN (52% among all identified sources). IRAS PSC/FSC sources were studied having accurate positions from WISE and a large extragalactic sample was created for further search for AGNs. The fraction of active galaxies among IR-selected galaxies was estimated as 24%. Variable radio sources at 1.4 GHz were revealed by cross-correlation of NVSS and FIRST catalogues using the method introduced by us for optical variability. Radio-X-ray sources were revealed from NVSS and ROSAT for detection of new active galaxies. Big Data in astronomy is described that provide new possibilities for statistical research of active galaxies and other objects.

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Optically bright active galactic nuclei in the ROSAT-Faint source catalogue

Cited by 12 publications

References 33 publications

A photometric catalogue of quasars and other point sources in the Sloan Digital Sky Survey

A photometric catalogue of quasars and other point sources in the Sloan Digital Sky Survey

Optical identification of ROSAT-FSC sources

Multi-wavelength studies of the statistical properties of active galaxies using Big Data

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