Modelling time delays from two reprocessors in active galactic nuclei

Jaiswal, Vikram Kumar; Prince, Raj; Panda, Swayamtrupta

doi:10.48550/arxiv.2206.12497

Cited by 4 publications

(5 citation statements)

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“…Although, details models which take into account both disk geometry and BLR contribution are required(see e.g. Jaiswal, Prince, Panda, & Czerny, 2022), further observations could also help to disentangle between these two different phenomena. For example, by performing multi-epoch detailed X-ray spectral-timing analysis at different stages of the campaign could help to constrain the inner geometry of the accretion flow (Mastroserio, Ingram, & van der Klis, 2020) and therefore quantify the real contribution of the BLR.…”

Section: Discussionmentioning

confidence: 99%

“…A dynamically evolving corona, as the one observed with pure X-ray spectral timing methods (e.g., Alston et al 2020), could play a significant role in at least driving the changing of the contribution from the diffuse continuum from the BLR to the overall multi-wavelength variability (Vincentelli et al 2021(Vincentelli et al , 2022. Although details models which take into account both disk geometry and BLR contribution are required(see e.g., Jaiswal et al 2022), further observations could also help to disentangle between these two different phenomena. For example, performing multi-epoch detailed X-ray spectral-timing analysis at different stages of the campaign could help to constrain the inner geometry of the accretion flow (Mastroserio et al 2020) and therefore quantify the real contribution of the BLR.…”

Section: Discussionmentioning

confidence: 99%

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The evolution of the UV/optical lag spectrum of NGC 7469 seen by the Liverpool Telescope

et al. 2023

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We present the results regarding the analysis of an intensive monitoring of the Active Galactic Nucleus (AGN) NGC 7469. We observed the source for 4 months with almost daily cadence in the ugriz bands, using the IO:O on the Liverpool Telescope. We measured the lags with respect to the u band and found a clear change of the lag spectrum between the first and the second half of the campaign. Given that the source varies on different timescales during these two segments, it is likely that different components are dominating the variability at different times. This result further confirms that reverberation models require a more complex geometry than a static illuminating point source and that particular attention has to be given in the interpretation of these delays.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The evolution of the UV/optical lag spectrum of NGC 7469 seen by the Liverpool Telescope

et al. 2023

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“…One way to distinguish between the effect of the position of the irradiating source and the contamination by the scattering medium (see Fig. 5) is discussed in Jaiswal et al (2022). However, in some sources, the effect may also be related to an incorrect estimate of the black hole mass (Pozo Nuñez et al 2014.…”

Section: Cosmology With Quasarsmentioning

confidence: 99%

Accretion disks, quasars and cosmology: meandering towards understanding

Czerny

Cao

Jaiswal

et al. 2023

Astrophys Space Sci

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As Setti and Woltjer noted back in 1973, one can use quasars to construct the Hubble diagram; however, the actual application of the idea was not that straightforward. It took years to implement the proposition successfully. Most ways to employ quasars for cosmology now require an advanced understanding of their structure, step by step. We briefly review this progress, with unavoidable personal biases, and concentrate on bright unobscured sources. We will mention the problem of the gas flow character close to the innermost stable circular orbit near the black hole, as discussed five decades ago. This problem later led to the development of the slim disk scenario and is recently revived in the context of Magnetically Arrested Disks (MAD) and Standard and Normal Evolution (SANE) models. We also discuss the hot or warm corona issue, which is still under debate and complicates the analysis of X-ray reflection. We present the scenario of the formation of the low ionization part of the Broad Line Region as a failed wind powered by radiation pressure acting on dust (Failed Radiatively Driven Dusty Outflow – FRADO). Next, we examine the cosmological constraints currently achievable with quasars, primarily concentrating on light echo methods (continuum time delays and spectral-line time delays to the continuum) that are (or should be) incorporating the progress mentioned above. Finally, we briefly discuss prospects in this lively subject area.

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“…Therefore, in the current paper, we simply assume the response function in the form of a symmetric Gaussian shape, with the time shift set by Equation 1, and the width σ BLR of 10% of the same delay. Exceptionally, we also performed tests using a half-Gaussian shape for this purpose, as done in the simulations of the time delay by Jaiswal et al (2022).…”

Section: Delayed Dense Lightcurvementioning

confidence: 99%

“…Thus, for the comparison, we performed simulations with the response function in the form of half-Gaussian (see e.g. Jaiswal et al 2022) but assuming the shift as implied by the formulae, and the width as in a standard model, i.e. 10 % of the time delay.…”

Section: Prediction Sensitivity On the Adopted Parametersmentioning

confidence: 99%

Expectations for time-delay measurements in active galactic nuclei with the Vera Rubin Observatory

Panda¹,

Prince²,

Jaiswal³

et al. 2023

Preprint

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Context. The Vera Rubin Observatory will provide an unprecedented set of time-dependent observations of the sky. The planned Legacy Survey of Space and Time (LSST) operating for 10 years will provide dense lightcurves for thousands of active galactic nuclei (AGN) in Deep Drilling Fields (DDFs) and less dense lightcurves for millions of AGN . Aims. In this paper, we model the prospects for measuring the time delays for the AGN emission lines with respect to the continuum, using these data. Methods. We model the artificial lightcurves using Timmer-König algorithm, we use the exemplary cadence to sample them (one for the Main Survey and one for the Deep Drilling Field), we supplement lightcurves with the expected contamination by the strong emission lines (Hβ, Mg II and CIV as well as with Fe II pseudo-continuum and the starlight). We choose the suitable photometric bands appropriate for the redshift and compare the assumed line time delay with the recovered time delay for 100 statistical realizations of the light curves. Results. We show that time delays for emission lines can be well measured from the Main Survey for the bright tail of the quasar distribution (about 15% of all sources) with the accuracy within 1σ error, for DDFs results for fainter quasars are also reliable when all 10 years of data are used. There are also some prospects to measure the time delays for the faintest quasars at the smallest redshifts from the first two years of data, and eventually even from the first season. The entire quasar population will allow obtaining results of apparently high accuracy but in our simulations, we see a systematic offset between the assumed and recovered time delay depending on the redshift and source luminosity which will not disappear even in the case of large statistics. Such a problem might affect the slope of the radius-luminosity relation and cosmological applications of quasars if simulations correcting for such effects are not performed.

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Modelling time delays from two reprocessors in active galactic nuclei

Cited by 4 publications

References 0 publications

The evolution of the UV/optical lag spectrum of NGC 7469 seen by the Liverpool Telescope

The evolution of the UV/optical lag spectrum of NGC 7469 seen by the Liverpool Telescope

Accretion disks, quasars and cosmology: meandering towards understanding

Expectations for time-delay measurements in active galactic nuclei with the Vera Rubin Observatory

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