XMM-Newton observation of the Lockman Hole - II. Spectral analysis

By V. Mainieri, J. Bergeron, G. Hasinger, I. Lehmann, Piero Rosati, M. Schmidt, G. Szokoly, R. Tre, E. Observatory, I. D. Paris and 4 more. 2002

175 citations recorded by the source corpus.

We present the results of the X-ray spectral analysis of the first deep X-ray survey with the XMM-Newton observa- tory during Performance Verification. The X-ray data of the Lockman Hole field and the derived cumulative source counts were reported by Hasinger et al. (2001). We restrict the analysis to the sample of 98 sources with more than 70 net counts (flux limit in the (0.5-7) keV band of 1:6 10 15 erg cm 2 s 1 ) of which 61 have redshift identification. We find no correlation between the spectral index and the intrinsic absorption column density NH and, for both the Type-1 and Type-2 AGN populations, we obtainh i' 2. The progressive hardening of the mean X-ray source spectrum with decreasing flux is essentially due to an increase in intrinsic absorption. The marked separation between the two AGN populations in several diagnostics diagrams, involving X-ray colour, X-ray flux, optical/near IR colour and optical brightness, is also a consequence of dierent absorption column densities and enables the classification of optically faint obscured AGN. The Type-2 and obscured AGN have weaker soft X-ray and optical fluxes and redder R K 0 colours. They follow the evolutionary tracks of their host galaxies in a color- redshift diagram. About 27% of the subsample with R K 0 colour are EROs (R K 0 5) and most of these 18 X-ray selected EROs contain an obscured AGN as revealed by their high X-ray-to-optical/near IR flux ratios. There are six sources in our sample with LX(0:5 10)> 10 44 erg s 1 and log(NH)> 10 22 cm 2 : which are likely Type-2 QSOs and we thus derive a density of69 objects of this class per square degree.

Subfields: Astronomy and Astrophysics, Statistics and Probability

View Paper: https://www.semanticscholar.org/paper/e6b9635823fb3c8295ca0a2d87c26fad1b496b47

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Statistics and Probability

Citations in the corpus

The XMM-Newton Wide-Field Survey in the COSMOS Field. I. Survey Description (2006, background): “This is consistent with similar simulations for the Lockman Hole (Brunner et al. 2006) and is also confirmed by the statistics of optically empty error circles in Brusa et al. (2007).”
Chandra and Spitzer Unveil Heavily Obscured Quasars in the Chandra/SWIRE Survey (2006, background): “Previous studies (Dwelly et al. 2005; Mainieri et al. 2002; Della Ceca et al. 2004; Perola et al. 2004) have shown that color-based analyses are effective in deriving the properties of X-ray sources with few counts.”
THE CHANDRA COSMOS LEGACY SURVEY: OPTICAL/IR IDENTIFICATIONS (2015, background): “The corresponding sample completeness and reliability for the catalogs in the three bands are shown in Table 3: as a general trend, both C and R grow moving from optical to infrared, due to the stronger relation of K or 3.6 µm magnitudes with the X-ray flux (Mainieri et al. 2002, Brusa et al. 2005).”
The XMM-Newton Wide-Field Survey in the COSMOS Field. III. Optical Identification and Multiwavelength Properties of a Large Sample of X-Ray-Selected Sources (2006, background): “The main advantage of using also this nearinfrared catalog is due to the fact that the X-ray to nearinfrared correlation for AGN is much tighter than the one in the optical bands (Mainieri et al. 2002; Brusa et al. 2005).”
The HELLAS2XMM Survey. VII. The Hard X-Ray Luminosity Function of AGNs up to z = 4: More Absorbed AGNs at Low Luminosities and High Redshifts (2005, background): “Optical identifications and X-ray spectral fits are from Mainieri et al. (2002).”
PHOTOMETRIC REDSHIFT AND CLASSIFICATION FOR THE XMM–COSMOS SOURCES (2008, background): “Type 1 AGN are expected to be in a narrow region with HR1∼ −0.5, while type 2 AGN and normal galaxies have higher HR1 values (Hasinger et al. 2001; Mainieri et al. 2002; Della Ceca et al. 2004; Hasinger et al. 2007; Cappelluti et al. 2008).”
The Fall of Active Galactic Nuclei and the Rise of Star-forming Galaxies: A Close Look at the Chandra Deep Field X-Ray Number Counts (2004, background): “…below this level several other populations emerge, such as obscured AGNs (e.g., Alexander et al. 2001; Tozzi et al. 2001; Barger et al. 2002; Mainieri et al. 2002) and starburst and quiescent galaxies (e.g., Giacconi et al. 2001; Alexander et al. 2002a; Bauer et al. 2002b; Hornschemeier et…”
The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei (2004, methodology): “Ultimately, many of the sources in these surveys will be pinned down with higher resolution Chandra or XMM-Newton observations and their counterparts robustly identified.”
The HELLAS2XMM survey IV. Optical identifications and the evolution of the accretion luminosity in the Universe (2003, background): “Fluxes are from Baldi et al. (2002), optical identifications are from Mainieri et al. (2002), for a total of 55 sources, 44 already identified (41 spectroscopic redshifts and 3 photometric redshifts); 3- SSA13 sample from Mushotzky et al. (2000) and Barger et al. (2001): 20 sources withF2−10 keV >…”
THE CHANDRA COSMOS SURVEY. III. OPTICAL AND INFRARED IDENTIFICATION OF X-RAY POINT SOURCES (2012, methodology): “Similar plots have been shown before in the K band by Mainieri et al. (2002) and Brusa et al. (2005) and at 3.6 µm by Xue et al. (2011) and Laird et al. (2008).”
The Chandra Deep Field North Survey. XIII. 2 Ms Point-Source Catalogs (2003, background): “Vol. 126 (2002) and Mainieri et al. (2002) from X-ray color-color analyses of bright X-ray sources.”
Unabsorbed Seyfert 2 galaxies (2002, background): “Recently, Mainieri et al. (2002) have presented the results of the X-ray spectral analysis of the deep survey of the Lockman Hole field with the XMM-Newton observatory.”
Luminosity-dependent evolution of soft X-ray selected AGN : New Chandra and XMM-Newton surveys (2005, methodology): “Due to the extreme faintness of the optical counterparts, the lowest identification fractions are achieved in the recent deepest samples: 87% for the XMM–Newton survey in the Lockman Hole and 88% in the CDF–N.”
Cosmological Evolution of the Hard X-Ray Active Galactic Nucleus Luminosity Function and the Origin of the Hard X-Ray Background (2003, methodology): “This value is also consistent with the mean photon index of the Lockman hole AGNs observed by XMM-Newton (Mainieri et al. 2002).”
The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era (2006, background): “The distribution of the power law indices around the mean is found to have a significant dispersion (σΓ ≃ 0.2–0.3; Mainieri et al. 2002, Mateos et al. 2005, Tozzi et al. 2006) which has always been neglected in previous synthesis models.”
Optical and Infrared Properties of the 2 Ms Chandra Deep Field North X-Ray Sources (2003, background): “The upper envelope of the photometrically identified sources tracks the elliptical galaxy curve, and at the higher redshifts, many of the galaxies fall into the ERO color range (see also Alexander et al. 2002b and Mainieri et al. 2002).”
Swift BAT Survey of AGNs (2007, methodology): “With the recent Chandra and XMM data (e.g., Alexander et al. 2003; Giacconi et al. 2002; Yang et al. 2004;Mainieri et al. 2002, 2005; Szokoly et al. 2004; Zheng et al. 2004; Barger et al. 2001, 2003) there has been great progress in understanding the origin of the X-ray background and the evolution…”