XMM-<i>Newton</i> spectroscopy of an X-ray  selected sample of RL AGNs

Galbiati, Eleonora; Caccianiga, A.; Maccacaro, T.; Braito, V.; Ceca, R. Della; Severgnini, P.; Brunner, H.; Lehmann, I.; Page, M. J.

doi:10.1051/0004-6361:20041716

Cited by 38 publications

(61 citation statements)

References 69 publications

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“…9 only includes LBL objects and that HBL sources make up two thirds the total contribution to the CXB (see above), the percentage scales to about 12% which is very close to the 11% obtained with the previous method. Both results are in good agreement with the independent estimate based on the XMM-Newton Bright Serendipitous Survey by Galbiati et al (2005), who conclude that the radio loud AGN content of the CXB is 13%.…”

Section: The Soft X-ray Backgroundsupporting

confidence: 90%

Non-thermal cosmic backgrounds from blazars: the contribution to the CMB, X-ray andγ-ray backgrounds

Giommi

Colafrancesco

Cavazzuti

et al. 2006

A&A

116

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We present a new assessment of the contribution of the blazar population to the extragalactic background radiation across the electromagnetic spectrum. Our calculations rely on deep blazar radio counts that we have derived by combining several radio and multi-frequency surveys. We show that blazar emission integrated over cosmic time gives rise to a considerable broad-band non-thermal cosmic background that in some parts of the electromagnetic spectrum dominates the extragalactic brightness. We confirm that blazars are the main discrete contributors to the Cosmic Microwave Background (CMB), where we estimate that their integrated emission causes an apparent temperature increase of 5−50 µK in the frequency range 50−250 GHz. The CMB primordial fluctuation spectrum is contaminated starting at multipole l ≈ 300−600, in the case of a completely random source distribution, or at lower l values if spatial clustering is present. We estimate that well over one hundred-thousand blazars will produce a significant signal in the maps of the upcoming Planck CMB anisotropy mission. Because of a tight correlation between the microwave and the X-ray flux, these sources are expected to be X-ray emitters with flux larger than a few 10 −15 erg cm −2 s −1 in the soft X-ray band. A large fraction of the foreground sources in current and near-future CMB anisotropy maps could therefore be identified and removed using a multi-frequency approach, provided that a sufficiently deep all-sky X-ray survey will become available in the near future. We show further that blazars are a major constituent of all high energy extragalactic backgrounds. Their contribution is expected to be 11−12% at X-ray frequencies and possibly 100% in the ∼0.5−50 MeV band. At higher energies (E > 100 MeV) the estimated blazar collective emission, obtained by extrapolating their integrated micro-wave flux to the γ-ray band using the SED of EGRET detected sources, overestimates the extragalactic background by a large factor, thus implying that not only blazars dominate the γ-ray sky but also that their average duty cycle at these frequencies must be rather low. Finally, we find that blazars of the HBL type may produce a significant amount of flux at TeV energies.

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Section: The Soft X-ray Backgroundsupporting

confidence: 90%

Non-thermal cosmic backgrounds from blazars: the contribution to the CMB, X-ray andγ-ray backgrounds

Giommi

Colafrancesco

Cavazzuti

et al. 2006

A&A

116

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“…Galbiati et al (2005) performed an analysis of the radio-loud AGN within the XBS. Severgnini et al (2003) unveiled the AGN-nature of three sources previously considered as normal galaxies.…”

Section: The Xbs Agn Samplementioning

confidence: 99%

“…For 111 AGN an X-ray spectral analysis was already reported and discussed in Severgnini et al (2003), Caccianiga et al (2004Caccianiga et al ( , 2007, Galbiati et al (2005) or in Della ; for the remaining AGN the main X-ray spectral properties and parameters are discussed in detail here for the first time. Note, however, that there could be small differences in the best-fit model and parameters already published and the ones presented here owing to the different XMM-Newton observations used and/or our different way of defining the best-fit model for each source.…”

Section: X-ray Spectral Analysismentioning

confidence: 99%

“…In other cases, the resulting photon index is ∼1, much lower than the typical values for unabsorbed AGN 3 . In those cases, we fixed Γ to 1.9, a common value for unabsorbed AGN Mateos et al 2005a,b;Galbiati et al 2005;Tozzi et al 2006;Mateos et al 2010). If there was no intrinsic absorption detected, an upper limit, at 90% confidence level, is given.…”

Section: X-ray Spectral Analysismentioning

confidence: 99%

“…Making use of the NVSS/XBS cross-correlation and analysis presented in Galbiati et al (2005), we removed all RL sources within these 267 type 1 AGN, which were 14 sources, and applied the same likelihood analysis by dividing into high-and low-luminosity AGN. We obtained the same result as for the whole sample, the only difference was a small decrement on the intrinsic dispersion for the high-luminosity subsample (σ = 0.19 ± 0.04), and the two samples were still different almost at the 3σ level.…”

Section: Photon Indexmentioning

confidence: 99%

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The X-ray spectral properties of the AGN population in theXMM-Newtonbright serendipitous survey

Corral

Ceca

Caccianiga

et al. 2011

A&A

Self Cite

130

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Context. X-ray surveys are a key instrument in the study of active galactic nuclei (AGN). Thanks to their penetrating ability, X-rays are able to map the innermost regions close to the central super massive black hole (SMBH) as well as to detect and characterize its emission up to high redshift. Aims. We present here a detailed X-ray spectral analysis of the AGN belonging to the XMM-Newton bright survey (XBS). The XBS is composed of two flux-limited samples selected in the complementary 0.5−4.5 and 4.5−7.5 keV energy bands and comprising more than 300 AGN up to redshift ∼2.4. Methods. We performed an X-ray analysis following two different approaches: by analyzing individually each AGN X-ray spectrum and by constructing average spectra for different AGN types. Results. From the individual analysis, we find that there seems to be an anti correlation between the spectral index and the sources' hard X-ray luminosity, such that the average photon index for the higher luminosity sources (>10 44 erg s −1 ) is significantly (>2σ) flatter than the average for the lower luminosity sources. We also find that the intrinsic column density distribution agrees with AGN unified schemes, although a number of exceptions are found (3% of the whole sample), which are much more common among optically classified type 2 AGN. We also find that the so-called "soft-excess", apart from the intrinsic absorption, constitutes the principal deviation from a power-law shape in AGN X-ray spectra and it clearly displays different characteristics, and likely a different origin, for unabsorbed and absorbed AGN. Regarding the shape of the average spectra, we find that it is best reproduced by a combination of an unabsorbed (absorbed) power law, a narrow Fe Kα emission line and a small (large) amount of reflection for unabsorbed (absorbed) sources. We do not significantly detect any relativistic contribution to the line emission and we compute an upper limit for its equivalent width (EW) of 230 eV at the 3σ confidence level. Finally, by dividing the type 1 AGN sample into high-and low-luminosity sources, we marginally detect a decrease in the narrow Fe Kα line EW and in the amount of reflection as the luminosity increases, the "so-called" Iwasawa-Taniguchi effect.

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Rolling down from the 30 keV peak: Modelling the hard X-ray and γ-ray backgrounds

Comastri¹,

Gilli²,

Hasinger³

2006

Focusing Telescopes in Nuclear Astrophysics

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XMM-Newton spectroscopy of an X-ray selected sample of RL AGNs

Cited by 38 publications

References 69 publications

Non-thermal cosmic backgrounds from blazars: the contribution to the CMB, X-ray andγ-ray backgrounds

Non-thermal cosmic backgrounds from blazars: the contribution to the CMB, X-ray andγ-ray backgrounds

The X-ray spectral properties of the AGN population in theXMM-Newtonbright serendipitous survey

Rolling down from the 30 keV peak: Modelling the hard X-ray and γ-ray backgrounds

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