Spectroscopic identification of ten faint hard X-ray sources discovered by Chandra

Fiore, F.; Franca, F. La; Vignali, C.; Comastri, A.; Matt, Giorgio; Perola, G. C.; Cappi, M.; Elvis, M.; Nicastro, F.

doi:10.1016/s1384-1076(00)00017-8

Cited by 80 publications

(77 citation statements)

References 37 publications

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“…Chandra observations have confirmed and extended down to lower fluxes these results (Mushotzky et al 2000;Fiore et al 2000b;Brandt et al 2000;Giacconi et al 2001;Barger et al 2001).…”

Section: Introductionmentioning

confidence: 65%

The BeppoSAX High Energy Large Area Survey

Vignali

Comastri

Fiore

et al. 2001

A&A

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Abstract. We present a comprehensive study of the soft X-ray properties of the BeppoSAX High-Energy Large Area Survey (HELLAS) sources. A large fraction (about 2/3) of the hard X-ray selected sources is detected by ROSAT. The soft X-ray colors for many of these objects, along with the 0.5-2 keV flux upper limits for those undetected in the ROSAT band, do imply the presence of absorption. The comparison with the ROSAT Deep Survey sources indicates that a larger fraction of absorbed objects among the HELLAS sources is present, in agreement with their hard X-ray selection and the predictions of the X-ray background synthesis models. Another striking result is the presence of a soft (additional) X-ray component in a significant fraction of absorbed objects.

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“…Chandra observations have confirmed and extended down to lower fluxes these results (Mushotzky et al 2000;Fiore et al 2000b;Brandt et al 2000;Giacconi et al 2001;Barger et al 2001).…”

Section: Introductionmentioning

confidence: 65%

The BeppoSAX High Energy Large Area Survey

Vignali

Comastri

Fiore

et al. 2001

A&A

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“…Sources with such properties are commonly identified as X-ray bright optically normal galaxies (XBONGs; Fiore et al 2000;Barger et al 2001;Comastri et al 2002;Georgantopoulos & Georgakakis 2005). They are usually found to host either heavily obscured or low luminosity AGN.…”

Section: Redshift and Luminosity Distributionsmentioning

confidence: 99%

TheXMM-NewtonWide Angle Survey (XWAS)

Esquej

Page

Carrera

et al. 2013

A&A

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Aims. This programme is aimed at obtaining one of the largest X-ray selected samples of identified active galactic nuclei to date in order to characterise such a population at intermediate fluxes, where most of the Universe's accretion power originates. We present the XMM-Newton Wide Angle Survey (XWAS), a new catalogue of almost a thousand X-ray sources spectroscopically identified through optical observations. Methods. A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fibre spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R ∼ 21, with preference for X-ray sources having a flux F 0.5−4.5 keV ≥ 10 −14 erg s −1 cm −2 . Optical spectroscopic observations were made using the Two Degree Field of the Anglo Australian Telescope, and the resulting spectra were classified based on optical emission lines. Results. We have identified through optical spectroscopy 940 X-ray sources over Ω ∼ 11.8 deg 2 of the sky. Source populations in our sample can be summarised as 65% broad line active galactic nuclei (BLAGN), 16% narrow emission line galaxies (NELGs), 6% absorption line galaxies (ALGs) and 13% stars. An active nucleus is also likely to be present in the large majority of the X-ray sources spectroscopically classified as NELGs or ALGs. Sources lie in high-galactic latitude (|b| > 20 deg) XMM-Newton fields mainly in the southern hemisphere. Owing to the large parameter space in redshift (0 ≤ z ≤ 4.25) and flux (10 −15 ≤ F 0.5−4.5 keV ≤ 10 −12 erg s −1 cm −2 ) covered by the XWAS this work provides an excellent resource for the further study of subsamples and particular cases. The overall properties of the extragalactic objects are presented in this paper. These include the redshift and luminosity distributions, optical and X-ray colours and X-ray-to-optical flux ratios.

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“…Fiore et al (2000) described the detection of 6 sources from a 2-10 keV image made by the 16 arcmin square ACIS-I detector. They then observed these objects with the ESO 3.6 m EFOSC2 spectrograph.…”

Section: The Observationmentioning

confidence: 99%

An XMM-Newton view of the serendipitous sources in the PKS0312-770 field

Lumb

Guainazzi

Gondoin

2001

A&A

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Abstract.We describe an XMM-Newton observation of the PKS0312-770 field, which facilitates the spectral analysis of serendipitous sources previously detected by CHANDRA. The combination of larger effective area and longer exposure duration allows a significant increase in detected photons, and a lower limit in source detection sensitivity. In particular the hard X-ray normal galaxy unveiled by Fiore et al. (2000) is most likely explained as a moderately absorbed (NH ∼ 10 22 cm −2 ) AGN. We detect 52 sources (45 previously unreported) at a limiting flux of ∼2 × 10 −15 ergs cm −2 s −1 in the 0.5-2 keV band. The Log N-Log S curve is consistent with that derived from by XMM-Newton observations of the Lockman Hole field. The flux determinations allow to check for any inconsistency between the calibrations of the two observatories, which is discussed.

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Spectroscopic identification of ten faint hard X-ray sources discovered by Chandra

Cited by 80 publications

References 37 publications

The BeppoSAX High Energy Large Area Survey

The BeppoSAX High Energy Large Area Survey

TheXMM-NewtonWide Angle Survey (XWAS)

An XMM-Newton view of the serendipitous sources in the PKS0312-770 field

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