XMMFITCAT: The<i>XMM-Newton</i>spectral-fit database

Corral, A.; Georgantopoulos, I.; Watson, M. G.; Rosen, S. R.; Page, K. L.; Webb, N.

doi:10.1051/0004-6361/201425124

Cited by 19 publications

(28 citation statements)

References 12 publications

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“…The photon index Γ is in the range [1.0, 3.0] during the fitting. We find an average value of Γ = 1.85 ± 0.4, in agreement with previous observations (Mainieri et al 2002(Mainieri et al , 2007Tozzi et al 2006;Buchner et al 2014;Corral et al 2015). The relative uncertainties associated with our fitting results vary as a function of X-ray spectral quality flag (as defined in Sect.…”

Section: X-ray Spectral Propertiessupporting

confidence: 91%

The XXL Survey

Fotopoulou

Pacaud

Paltani

et al. 2016

A&A

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Context. X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). Usually, a combination of deep and wide surveys is necessary to create a complete picture of the population. Deep X-ray surveys provide the faint population at high redshift, while wide surveys provide the rare bright sources. Nevertheless, very wide area surveys often lack the ancillary information available for modern deep surveys. The XXL survey spans two fields of a combined 50 deg 2 observed for more than 6Ms with XMM-Newton, occupying the parameter space that lies between deep surveys and very wide area surveys; at the same time it benefits from a wealth of ancillary data. Aims. This paper marks the first release of the XXL point source catalogue including four optical photometry bands and redshift estimates. Our sample is selected in the 2−10 keV energy band with the goal of providing a sizable sample useful for AGN studies. The limiting flux is F 2−10 keV = 4.8 × 10 −14 erg s −1 cm −2 . Methods. We use both public and proprietary data sets to identify the counterparts of the X-ray point-like sources by means of a likelihood ratio test. We improve upon the photometric redshift determination for AGN by applying a Random Forest classification trained to identify for each object the optimal photometric redshift category (passive, star forming, starburst, AGN, quasi-stellar objects (QSO)). Additionally, we assign a probability to each source that indicates whether it might be a star or an outlier. We apply Bayesian analysis to model the X-ray spectra assuming a power-law model with the presence of an absorbing medium. Results. We find that the average unabsorbed photon index is Γ = 1.85 ± 0.40 while the average hydrogen column density is log N H = 21.07 ± 1.2 cm −2 . We find no trend of Γ or N H with redshift and a fraction of 26% absorbed sources (log N H > 22) consistent with the literature on bright sources (log L x > 44). The counterpart identification rate reaches 96.7% for sources in the northern field, 97.7% for the southern field, and 97.2% in total. The photometric redshift accuracy is 0.095 for the full XMM-XXL with 28% catastrophic outliers estimated on a sample of 339 sources. Conclusions. We show that the XXL-1000-AGN sample number counts extended the number counts of the COSMOS survey to higher fluxes and are fully consistent with the Euclidean expectation. We constrain the intrinsic luminosity function of AGN in the 2−10 keV energy band where the unabsorbed X-ray flux is estimated from the X-ray spectral fit up to z = 3. Finally, we demonstrate the presence of a supercluster size structure at redshift 0.14, identified by means of percolation analysis of the XXL-1000-AGN sample. The XXL survey, reaching a medium flux limit and covering a wide area, is a stepping stone between current deep fields and planned wide area surveys.

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Section: X-ray Spectral Propertiessupporting

confidence: 91%

The XXL Survey

Fotopoulou

Pacaud

Paltani

et al. 2016

A&A

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“…The distribution of goodness is presented in Figure 6. The fits are acceptable (goodness < 50%, e.g., Corral et al 2015) for all our sources. The worst case is J033218.3-275055 with goodness=44%, a Compton-thick candidate reported in the literature (Tozzi et al 2006;Comastri et al 2011).…”

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confidence: 67%

Long-Term X-Ray Variability of Typical Active Galactic Nuclei in the Distant Universe

Yang

Brandt

Luo

et al. 2016

ApJ

106

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We perform long-term (≈15 years, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6 Ms Chandra Deep Field-South survey; the majority are in the redshift range of 0.6-3.1, providing access to penetrating rest-frame X-rays up to ≈10-30 keV. Of the 68 sources, 24 are optical spectral typeI AGNs, and the rest (44) are type II AGNs. The timescales probed in this work are among the longest for X-ray variability studies of distant AGNs. Photometric analyses reveal widespread photon flux variability: 90% of AGNs are variable above a 95% confidence level, including many X-ray obscured AGNs and several optically classified type II quasars. We characterize the intrinsic X-ray luminosity (L X ) and absorption (N H ) variability via spectral fitting. Most (74%) sources show L X variability; the variability amplitudes are generally smaller for quasars. A Compton-thick candidate AGN shows variability of its high-energy X-ray flux, indicating the size of reflecting material to be 0.3 pc. L X variability is also detected in a broad absorption line quasar. The N H variability amplitude for our sample appears to rise as time separation increases. About 16% of sources show N H variability. One source transitions from an X-ray unobscured to obscured state, while its optical classification remains type I; this behavior indicates the X-ray eclipsing material is not large enough to obscure the whole broadline region.

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“…In the near future, the database will be enriched by the multi-wavelength statistical identifications and associated spectral energy distributions computed within the ARCHES project (Motch & Arches Consortium 2014). Spectral fitting results from the XMMFITCAT database (Corral et al 2015) are also partially available.…”

Section: External Catalogue Cross-correlationmentioning

confidence: 99%

TheXMM-Newtonserendipitous survey

Rosen

Webb

Watson

et al. 2016

A&A

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320

150

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Context. Thanks to the large collecting area (3 × ∼1500 cm 2 at 1.5 keV) and wide field of view (30 across in full field mode) of the X-ray cameras on board the European Space Agency X-ray observatory XMM-Newton, each individual pointing can result in the detection of up to several hundred X-ray sources, most of which are newly discovered objects. Since XMM-Newton has now been in orbit for more than 15 yr, hundreds of thousands of sources have been detected. Aims. Recently, many improvements in the XMM-Newton data reduction algorithms have been made. These include enhanced source characterisation and reduced spurious source detections, refined astrometric precision of sources, greater net sensitivity for source detection, and the extraction of spectra and time series for fainter sources, both with better signal-to-noise. Thanks to these enhancements, the quality of the catalogue products has been much improved over earlier catalogues. Furthermore, almost 50% more observations are in the public domain compared to 2XMMi-DR3, allowing the XMM-Newton Survey Science Centre to produce a much larger and better quality X-ray source catalogue. Methods. The XMM-Newton Survey Science Centre has developed a pipeline to reduce the XMM-Newton data automatically. Using the latest version of this pipeline, along with better calibration, a new version of the catalogue has been produced, using XMM-Newton X-ray observations made public on or before 2013 December 31. Manual screening of all of the X-ray detections ensures the highest data quality. This catalogue is known as 3XMM. Results. In the latest release of the 3XMM catalogue, 3XMM-DR5, there are 565 962 X-ray detections comprising 396 910 unique X-ray sources. Spectra and lightcurves are provided for the 133 000 brightest sources. For all detections, the positions on the sky, a measure of the quality of the detection, and an evaluation of the X-ray variability is provided, along with the fluxes and count rates in 7 X-ray energy bands, the total 0.2-12 keV band counts, and four hardness ratios. With the aim of identifying the detections, a cross correlation with 228 catalogues of sources detected in all wavebands is also provided for each X-ray detection. Conclusions. 3XMM-DR5 is the largest X-ray source catalogue ever produced. Thanks to the large array of data products associated with each detection and each source, it is an excellent resource for finding new and extreme objects.Key words. catalogs -astronomical databases: miscellaneous -surveys -X-rays: general Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.The catalogue is available at http://cdsarc.u-strasbg.fr/ viz-bin/VizieR?-meta.foot&-source=IX/46

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XMMFITCAT: TheXMM-Newtonspectral-fit database

Cited by 19 publications

References 12 publications

The XXL Survey

The XXL Survey

Long-Term X-Ray Variability of Typical Active Galactic Nuclei in the Distant Universe

TheXMM-Newtonserendipitous survey

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