Association of optical, ultraviolet, and soft X-ray excess emissions in AGNs

Nour, D.; Sriram, K.

doi:10.1093/mnras/stac3505

Association of optical, ultraviolet, and soft X-ray excess emissions in AGNs

Journal Article · Thu Dec 01 00:00:00 EST 2022 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stac3505· OSTI ID:1903409

Nour, D. ^[1]; Sriram, K. ^[2]

Osmania University, Hyderabad (India); Al Baath University, Homs (Syria)
Osmania University, Hyderabad (India)

Soft X-ray emission (0.5–2.0 keV) plays a pivotal role in regulating the optical and ultraviolet (UV) emission in the active galactic nuclei (AGNs). We collected a sample of 1811 AGNs from the SDSS database and obtained various parameters of Balmer lines, optical continuum, Mg ii line & UV continuum and studied their dependencies on soft X-ray luminosity. Based on the linear regression analysis, we found that FWHM$$_{\rm {Mg\,\,\small {II}}}$$ ∝ FWHM$$_{\text{H}\beta }^{0.554}$$ suggesting that UV emission is arising from a region relatively outside the broad-line region (BLR) associated to the Hβ emission and found a strong correlation between optical and UV luminosities (L$$_{\rm {Mg\,\,\small {II}}}$$ ∝ $$L_{\rm {H}\beta }^{0.822}$$). It was noticed that the dependency of optical continuum luminosities on soft excess changes with the redshift (L_X ∝ L$$^{0.596}_{5100\, \mathring{\rm A}}$$ for z < 0.5 and L_X ∝ L$$^{0.429}_{5100\, \mathring{\rm A}}$$ for z > 0.5). The full width at half-maximum components of Hβ and Mg II core components were found to be virialized and is not affected by the soft excess emission whereas the wings of Mg II display a dependency. We estimated a relation viz. L_X ∝L$$^{0.520}_{3000\, \mathring{\rm A}}$$ FWHM$$^{0.525}_{\rm {Mg\,\,\small {II}}}$$ and found to be well in agreement with a proposed physical scenario. All the derived relations were used to understand the intermodulating association of the BLR and disc in the AGNs.

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Research Organization:: US Department of Energy (USDOE), Washington, DC (United States). Office of Science, Sloan Digital Sky Survey (SDSS)

Sponsoring Organization:: USDOE

OSTI ID:: 1903409

Alternate ID(s):: OSTI ID: 2425107

Journal Information:: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 4 Vol. 518; ISSN 0035-8711

Publisher:: Oxford University PressCopyright Statement

Country of Publication:: United States

Language:: English

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