Redshift evolution of X-ray spectral index of quasars observed by XMM-NEWTON/SDSS

Shehata, Sh.M.; Misra, Ranjeev; Osman, Anas; Shalabiea, Osama M.; Hayman, Z. M.

doi:10.1016/j.jheap.2021.04.003

Cited by 5 publications

(5 citation statements)

References 33 publications

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“…7 right panel, as expected given that there is no obvious physical reason why a higher flux should be linked to column density, consistent with prior studies (e.g. Shehata et al 2021).…”

Section: Igm Column Density and Spectral Countssupporting

confidence: 90%

“…Given the luminosity bias in our sample, and the observed luminosity redshift relation in both our sample and the full SDSS-XMM-Newton catalogue, it is not surprising that there is also an apparent Nhxigm luminosity relation. This relation has been noted previously and it is not possible to determine which parameter of either luminosity or redshift, that Nhxigm is more closely related (Eitan & Behar 2013;Shehata et al 2021), or whether the luminosity relationship is causal in any way on Nhxigm. The results of Nhxigm redshift relations for other tracers in Section 6 should help clarify this point.…”

Section: Igm Column Density and Luminositymentioning

confidence: 88%

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Probing the parameters of the intergalactic medium using quasars

Dalton,

Morris,

Fumagalli

et al. 2022

Preprint

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We continue our series of papers on intergalactic medium (IGM) tracers using quasi-stellar objects (QSOs), having examined gamma-ray bursts (GRBs) and blazars in earlier studies. We have estimated the IGM properties of hydrogen column density (Nhxigm), temperature and metallicity using XMM-Newton QSO spectra over a large redshift range, with a collisional ionisation equilibrium (CIE) model for the ionised plasma. The Nhxigm parameter results were robust with respect to intrinsic power laws, spectral counts, reflection hump and soft excess features. There is scope for a luminosity bias given both luminosity and Nhxigm scale with redshift, but we find this unlikely given the consistent IGM parameter results across the other tracer types reviewed. The impact of intervening high column density absorbers was found to be minimal. The Nhxigm from the QSO sample scales as (1 + z) 1.5±0.2 . The mean hydrogen density at z = 0 is n 0 = (2.8 ± 0.3) × 10 −7 cm −3 , the mean IGM temperature over the full redshift range is log(T /K) = 6.5±0.1, and the mean metallicity is [X/H] = −1.3±0.1(Z ∼ 0.05). Aggregating with our previous GRB and blazar tracers, we conclude that we have provided evidence of the IGM contributing substantially and consistently to the total X-ray absorption seen in the spectra. These results are based on the necessarily simplistic slab model used for the IGM, due to the inability of current X-ray data to constrain the IGM redshift distribution.

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“…7 right panel, as expected given that there is no obvious physical reason why a higher flux should be linked to column density, consistent with prior studies (e.g. Shehata et al 2021).…”

Section: Igm Column Density and Spectral Countssupporting

confidence: 90%

Section: Igm Column Density and Luminositymentioning

confidence: 88%

Probing the parameters of the intergalactic medium using quasars

Dalton,

Morris,

Fumagalli

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Reeves & Turner 2000 ;Page et al 2005 ;Scott et al 2011 ), which is consistent with our results. 2006 ; Shehata et al 2021 ). This supports the argument that the observed N HX redshift relation in our results is IGM related and not intrinsic to the QSO properties, as there is no apparent relation between our N HXIGM results and power-law index in Fig.…”

Section: Igm Column Density and Intrinsic Power-law Indexsupporting

confidence: 89%

“…7 (right-hand panel), as expected given that there is no obvious physical reason why a higher flux should be linked to column density, consistent with prior studies (e.g. Shehata et al 2021 ).…”

Section: Igm Column Density and Spectral Countssupporting

confidence: 89%

“…Given the luminosity bias in our sample, and the observed luminosity redshift relation in both our sample and the full SDSS-XMM-Newton catalogue, it is not surprising that there is also an apparent N HXIGM luminosity relation. This relation has been noted previously and it is not possible to determine which parameter of either luminosity or redshift, that N HXIGM is more closely related(Eitan & Behar 2013 ;Shehata et al 2021 ), or whether the luminosity relationship MNRAS 513,822-834 (2022)…”

mentioning

confidence: 91%

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Probing the parameters of the intergalactic medium using quasars

Dalton

Morris

Fumagalli

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We continue our series of papers on intergalactic medium (IGM) tracers using quasi-stellar objects (QSOs), having examined gamma-ray bursts (GRBs) and blazars in earlier studies. We have estimated the IGM properties of hydrogen column density ($\mathit {N}\small {\rm hxigm}$), temperature and metallicity using XMM-Newton QSO spectra over a large redshift range, with a collisional ionisation equilibrium (CIE) model for the ionised plasma. The $\mathit {N}\small {\rm hxigm}$ parameter results were robust with respect to intrinsic power laws, spectral counts, reflection hump and soft excess features. There is scope for a luminosity bias given both luminosity and $\mathit {N}\small {\rm hxigm}$ scale with redshift, but we find this unlikely given the consistent IGM parameter results across the other tracer types reviewed. The impact of intervening high column density absorbers was found to be minimal. The $\mathit {N}\small {\rm hxigm}$ from the QSO sample scales as (1 + z)1.5 ± 0.2. The mean hydrogen density at z = 0 is n0 = (2.8 ± 0.3) × 10−7 cm−3, the mean IGM temperature over the full redshift range is log(T/K) =6.5 ± 0.1, and the mean metallicity is [X/H] = −1.3 ± 0.1(Z ∼ 0.05). Aggregating with our previous GRB and blazar tracers, we conclude that we have provided evidence of the IGM contributing substantially and consistently to the total X-ray absorption seen in the spectra. These results are based on the necessarily simplistic slab model used for the IGM, due to the inability of current X-ray data to constrain the IGM redshift distribution.

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Dependency of optical/UV parameters on X-ray spectral index in AGNs

Nour

Sriram

2023

Journal of High Energy Astrophysics

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Redshift evolution of X-ray spectral index of quasars observed by XMM-NEWTON/SDSS

Cited by 5 publications

References 33 publications

Probing the parameters of the intergalactic medium using quasars

Probing the parameters of the intergalactic medium using quasars

Probing the parameters of the intergalactic medium using quasars

Dependency of optical/UV parameters on X-ray spectral index in AGNs

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