Orientation effects on the near-infrared broad-band emission of quasars

Bisogni, S.; Lusso, Elisabeta; Marconi, A.; Risaliti, G.

doi:10.1093/mnras/stz495

Cited by 8 publications

(7 citation statements)

References 47 publications

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“…The results indicate no obvious correlations. It means the mid-infrared emission from jet contribution is weak in radio-loud quasars which is consistent with the view of Bisogni et al (2019), and implies that the emission of radio-loud quasars in mid-infrared band is dominated by the thermal emission from dusty torus.…”

Section: The Relation Between the Variability Amplitude In Mid-infrar...supporting

confidence: 83%

“…Mao et al (2018) showed γray blazars had larger mid-IR variability than non-γ-ray blazars. Bisogni et al (2019) showed the infrared bump cannot be induced by synchrotron emission form the blazar-like objects, and found no difference between radio quiet and radio-loud objects in the stacked mid-infrared spectral energy distribution. Rakshit et al (2019) found a positive correlation between the variability amplitude and 1.4 GHz radio power by analyzing 63 radio-detected Narrow Line Seyfert 1 galaxies.…”

Section: The Relation Between the Variability Amplitude In Mid-infrar...mentioning

confidence: 96%

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School of Teacher, Nanjing Xiao Zhuang University, Nanjing, 210000, China

Wang¹

2017

Advances in Psychological Science

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The nuclide 14 C can be produced in the atmosphere by high energy particles and γ-rays from high-energy phenomena. Through the carbon cycle, some of 14 CO 2 produced in the atmosphere can be retained in annual tree rings 1, 2 . Four events of rapid increase of the 14 C content occurred in AD 775, AD 994, BC 660 and BC 3371 were found 3-6 . Recently, the data of Jull et al. (2020) was inconsistent with our records around BC 3371. We measured our sample again and found the 14 C records are consistent with the value in Wang et al. (2017). Therefore, our 14 C records are robust. The inconsistency may be caused by the difference of calendar ages for the wood samples, or the physical origin of the event. First, crossdating on ring width can be performed only between trees whose growth has the same environmental conditions. Because the master tree-ring for dendrochronology is lack for Chinese trees. The master tree-ring from California has to be used. Therefore, the calendar ages derived from dendrochronology may be not precise. Second, the 14 C even may be not global. One evidence

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Section: The Relation Between the Variability Amplitude In Mid-infrar...supporting

confidence: 83%

Section: The Relation Between the Variability Amplitude In Mid-infrar...mentioning

confidence: 96%

School of Teacher, Nanjing Xiao Zhuang University, Nanjing, 210000, China

Wang¹

2017

Advances in Psychological Science

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“…We are planning to apply a correction for the disc inclination with respect to the line of sight by making use of the rest-frame equivalent width of the [O iii] emission line, EW[O iii], for the sources for which this line is available in SDSS (z < 0.8). This quantity has been proposed by our group as an orientation indicator of the accretion disc (Risaliti et al 2011;Bisogni et al 2017bBisogni et al , 2019. We will further analyse this aspect in a future work.…”

Section: Additional Contributions To the Dispersionmentioning

confidence: 90%

The Chandra view of the relation between X-ray and UV emission in quasars

Bisogni

Lusso

Civano

et al. 2021

A&A

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We present a study of the relation between X-rays and ultraviolet emission in quasars for a sample of broad-line, radio-quiet objects obtained from the cross-match of the Sloan Digital Sky Survey DR14 with the latest Chandra Source Catalog 2.0 (2332 quasars) and the Chandra COSMOS Legacy survey (273 quasars). The non-linear relation between the ultraviolet (at 2500 Å, LUV) and the X-ray (at 2 keV, LX) emission in quasars has been proved to be characterised by a smaller intrinsic dispersion than the observed one, as long as a homogeneous selection, aimed at preventing the inclusion of contaminants in the sample, is fulfilled. By leveraging on the low background of Chandra, we performed a complete spectral analysis of all the data available for the SDSS-CSC2.0 quasar sample (i.e. 3430 X-ray observations), with the main goal of reducing the uncertainties on the source properties (e.g. flux, spectral slope). We analysed whether any evolution of the LX − LUV relation exists by dividing the sample in narrow redshift intervals across the redshift range spanned by our sample, z ≃ 0.5−4. We find that the slope of the relation does not evolve with redshift and it is consistent with the literature value of 0.6 over the explored redshift range, implying that the mechanism underlying the coupling of the accretion disc and hot corona is the same at the different cosmic epochs. We also find that the dispersion decreases when examining the highest redshifts, where only pointed observations are available. These results further confirm that quasars are ‘standardisable candles’, that is we can reliably measure cosmological distances at high redshifts where very few cosmological probes are available.

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“…Recent study by Bisogni et al (2019) shows that the low EW[O III] sources are face-on view and have more flatter IR/optical SED compared to the high EW[O III] sources, which have edge-on view with respect to the observer. They also claim that their finding suggest the torus to be clumpy.…”

Section: Advanced Torus Modelsmentioning

confidence: 99%

Viewing angle effects in quasar application to cosmology

Prince,

Czerny,

Pollo

2021

Preprint

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The symmetry axes of active galactic nuclei (AGN) are randomly distributed in space but highly inclined sources are heavily obscured and are not seen as quasars with broad emission lines. The obscuring torus geometry determines the average viewing angle, and if the torus geometry changes with the redshift, this average viewing angle will also change. Thus the ratio between the isotropic luminosity and observed luminosity may change systematically with redshift. Therefore, if we use quasars to measure the luminosity distance by evaluating the isotropic absolute luminosity and measuring the observed flux, we can have a redshift-dependent bias which can propagate to cosmological parameters. We propose a toy model for testing the effect of viewing angle uncertainty on measurement of the luminosity distance. The model is based on analytical description of the obscuring torus applied to one-parameter observational data. It illustrates the possible change of the torus covering factor between the two chosen redshift ranges. We have estimated the possible error on specific cosmological parameters (H 0 , Ω m ) for the flat ΛCDM cosmology if a method is calibrated at low redshift and applied to the higher redshift. The errors on cosmological parameters due to potential dependence of viewing angle on redshift are found to be potentially significant, and the effect will have to be accommodated in the future in all quasar-based cosmological methods. A careful systematic study of AGN mean viewing angle across redshift is necessary, with the use of appropriate samples and models which uniquely determine the inclination of each source.

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Orientation effects on the near-infrared broad-band emission of quasars

Cited by 8 publications

References 47 publications

School of Teacher, Nanjing Xiao Zhuang University, Nanjing, 210000, China

School of Teacher, Nanjing Xiao Zhuang University, Nanjing, 210000, China

The Chandra view of the relation between X-ray and UV emission in quasars

Viewing angle effects in quasar application to cosmology

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