X-ray spectra of the RIXOS source sample

Mittaz, J. P. D.; Carrera, Francisco J.; Romero-Colmenero, E.; Mason, K. O.; Hasinger, G.; McMahon, R. G.; Andernach, H.; Bower, Richard G.; Burgos-Martin, J.; Gonzalez-Serrano, J. I.; Wonnacott, David

doi:10.1046/j.1365-8711.1999.02750.x

Cited by 26 publications

(42 citation statements)

References 42 publications

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“…However the amount of observational results that cannot be explained in terms of the unified model of AGN is also significant. There is a substantial number of type-1 AGN for which X-ray absorption has been detected (Mittaz et al 1999;Fiore et al 2001;Page et al 2001;Schartel et al 2001;Tozzi et al 2001b;Mainieri et al 2002;Brusa et al 2003;Page et al 2003;Carrera et al 2004;Perola et al 2004;Mateos et al 2005), as well as Seyfert 2 galaxies unabsorbed in X-rays (Pappa et al 2001;Panessa et al 2002;Barcons et al 2003;Mateos et al 2005). The origin of the X-ray absorption in type-1 AGN is still not clear.…”

Section: Introductionmentioning

confidence: 99%

XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN

Mateos

Barcons

Carrera

et al. 2005

A&A

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110

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This paper presents the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources detected with XMM-Newton in the Lockman Hole field. This is the deepest observation carried out with XMM-Newton with more that 600 ks of good EPIC-pn data. We have spectra with good signal to noise (>500 source counts) for all objects down to 0.2−12 keV fluxes of ∼5 × 10 −15 erg cm −2 s −1 (flux limit of ∼6 × 10 −16 erg cm −2 s −1 in the 0.5−2 and 2−10 keV bands). At the time of the analysis, we had optical spectroscopic identifications for 60% of the sources, 46 being optical type-1 AGN and 28 optical type-2 AGN. Using a single power law model our sources' average spectral slope hardens at faint 0.5−2 keV fluxes but not at faint 2−10 keV fluxes. We have been able to explain this effect in terms of an increase in X-ray absorption at faint fluxes. We did not find in our data any evidence for the existence of a population of faint intrinsically harder sources. The average spectral slope of our sources is ∼1.9, with an intrinsic dispersion of ∼0.28. We detected X-ray absorption (F-test significance ≥95%) in 37% of the sources, ∼10% in type-1 AGN (rest-frame N H ∼ 1.6 × 10 21 −1.2 × 10 22 cm −2 ) and ∼77% (rest-frame N H ∼ 1.5 × 10 21 −4 × 10 23 cm −2 ) in type-2 AGN. Using X-ray fluxes corrected for absorption, the fraction of absorbed objects and the absorbing column density distribution did not vary with X-ray flux. Our type-1 and type-2 AGN do not appear to have different continuum shapes, but the distribution of intrinsic (rest-frame) absorbing column densities is different among both classes. A significant fraction of our type-2 AGN (5 out of 28) were found to display no substantial absorption (N H < 10 21 cm −2 ). We discuss possible interpretations to this in terms of Compton-thick AGN and intrinsic Broad Line Region properties. An emission line compatible with Fe Kα was detected in 8 sources (1 type-1 AGN, 5 type-2 AGN and 2 unidentified) with rest frame equivalent widths 120−1000 eV. However weak broad components can be easily missed in other sources by the relatively noisy data. The AGN continuum or intrinsic absorption did not depend on X-ray luminosity and/or redshift. Soft excess emission was detected in 18 objects, but only in 9 (including 4 type-1 AGN and 4 type-2 AGN) could we fit this spectral component with a black body model. The measured 0.5−2 keV luminosities of the fitted black body were not significantly different in type-1 and type-2 AGN, although the temperatures of the black body were slightly higher in type-2 AGN ( kT = 0.26 ± 0.08) than in type-1 AGN ( kT = 0.09 ± 0.01). For 9 sources (including 1 type-1 AGN and 3 type-2 AGN) a scattering model provided a better fit of the soft excess emission. We found that the integrated contribution from our sources to the X-ray background in the 2−7 keV band is softer (Γ = 1.5−1.6) than the background itself, implying that fainter sources need to be more absorbed.

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Section: Introductionmentioning

confidence: 99%

XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN

Mateos

Barcons

Carrera

et al. 2005

A&A

Self Cite

110

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“…There are not enough counts in the jet-like feature to do a detailed spectral analysis. However, the hardness ratios in Table 2 of the sources detected therein indicate a somewhat harder spectrum than the power law spectrum with photon index of 1.7 of NGC 6217 (see Mittaz et al 1999 and HR1 1.0, HR2 ∼ 0.2 compared to 0.89 and 0.00). While the feature is clearly extended from NGC 6217 to the SW it cannot be resolved by the PSPC in the perpendicular direction.…”

Section: Observations and Resultsmentioning

confidence: 94%

“…Mittaz et al (1999) characterized the X-ray spectra of the extragalactic objects in the RIXOS survey based on power law fits on three broad-band X-ray colors assuming galactic absorption. This method only gives reasonable fits if the intrinsic spectrum really can be described by a power law.…”

Section: Observations and Resultsmentioning

confidence: 99%

A possible X-ray jet from the starburst galaxy NGC 6217

Pietsch

Arp

2001

A&A

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Abstract. Deep ROSAT PSPC and HRI observations of the nuclear starburst, UV flat spectrum spiral NGC 6217 reveal a jet-like X-ray filament extending out 2. 7 (18.8 kpc) to the SW of the galaxy. Radio images of NGC 6217 show an extent in the same direction, giving further evidence for a one-sided X-ray jet interpretation of this feature. Its X-ray spectrum is harder than that of NGC 6217 and the luminosity in the 0.5-2.0 keV band is ∼1.7 ×10 39 erg s −1 . We compare our findings to parameters of other X-ray jets from other active galaxies. We also give positions of a total of 91 X-ray sources detected in the field to a limiting 0.5-2.0 keV flux of ∼2.2 ×10 −15 erg cm −2 s −1 and propose optical and radio identifications. Some of these sources have been identified in the RIXOS program.

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“…The average dust color temperature in the region was determined to be 27±4 K. We also determined the dust temperature distribution throughout the nebular region by dividing the 100 mm map by the 60 mm map and comparing the resulting I(100mm)/ I(60mm) values at each map location with the values given for dust grain models by Mittaz (1999). We found that the dust color temperature of the southern nucleus is 34±4 K and the temperature of its northern counterpart 32±4 K. The eastern filamentary structures are slightly cooler (20±2 K) than the western filamentary structures (26±3 K).…”

Section: Temperature Distance and Mass Estimatementioning

confidence: 99%

Retracted: Temperature and Mass Profile of Far-infrared Skeleton Nebula

Aryal

2017

Himalayan Physics

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X-ray spectra of the RIXOS source sample

Cited by 26 publications

References 42 publications

XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN

XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN

A possible X-ray jet from the starburst galaxy NGC 6217

Retracted: Temperature and Mass Profile of Far-infrared Skeleton Nebula

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