Continuum reverberation mapping in a<i>z</i>= 1.41 radio-loud quasar

Goicoechea, L. J.; Shalyapin, V. N.; Gil-Merino, R.; Braga, V. F.

doi:10.1088/1742-6596/372/1/012058

Cited by 3 publications

(5 citation statements)

References 13 publications

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“…On the other hand, mass accretion fluctuations propagate from outer to inner radii in the accretion disc, which means that the flux variations caused by the mass accretion fluctuations occur at the optical (longer) wavelengths prior to the UV (shorter) wavelengths (e.g., Arévalo et al 2008;Uttley & Casella 2014). Within the UV-optical wavelength range, the inter-band time delay of the AGN continuum for several AGNs are reported to be as expected in the reprocessing model (e.g., Collier et al 1999;Sergeev et al 2005;Suganuma et al 2006;Czerny & Janiuk 2007;Cackett, Horne & Winkler 2007;Goicoechea et al 2012;Chelouche 2013;Lohfink et al 2014;Shappee et al 2014;McHardy et al 2014;Edelson et al 2015), although results from different observing campaigns are conflicting (see, e.g., Nandra et al 1998;Uttley 2006). Moreover, several authors have pointed out that the X-ray luminosity of AGNs is insufficient to power the large UV-optical variability amplitude (e.g., Antonucci et al 1996;Gaskell 2008;Edelson et al 2014;Uttley & Casella 2014).…”

Section: Discussionmentioning

confidence: 75%

Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability

Kokubo

2015

Monthly Notices of the Royal Astronomical Society

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The physical mechanisms of the quasar ultraviolet (UV)-optical variability are not well understood despite the long history of observations. Recently, Dexter & Agol presented a model of quasar UV-optical variability, which assumes large local temperature fluctuations in the quasar accretion discs. This inhomogeneous accretion disc model is claimed to describe not only the single-band variability amplitude, but also microlensing size constraints and the quasar composite spectral shape. In this work, we examine the validity of the inhomogeneous accretion disc model in the light of quasar UV-optical spectral variability by using five-band multi-epoch light curves for nearly 9 000 quasars in the Sloan Digital Sky Survey (SDSS) Stripe 82 region. By comparing the values of the intrinsic scatter σ int of the two-band magnitude−magnitude plots for the SDSS quasar light curves and for the simulated light curves, we show that Dexter & Agol's inhomogeneous accretion disc model cannot explain the tight inter-band correlation often observed in the SDSS quasar light curves. This result leads us to conclude that the local temperature fluctuations in the accretion discs are not the main driver of the several years' UV-optical variability of quasars, and consequently, that the assumption that the quasar accretion discs have large localized temperature fluctuations is not preferred from the viewpoint of the UV-optical spectral variability.

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Section: Discussionmentioning

confidence: 75%

Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability

Kokubo

2015

Monthly Notices of the Royal Astronomical Society

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“…The future constraints on size of sources will be compared to current results from microlensing analyses (e.g. Refsdal et al 2000;Hainline et al 2012) and reverberation mapping techniques Goicoechea et al 2012). The main results from LT polarimetric observations are presented in Table 7.…”

Section: Summary and Prospectsmentioning

confidence: 99%

“…There is also strong evidence supporting the presence of a centrally irradiated AD in the heart of QSO B0957+561. A Chandra-UVOT-LT monitoring campaign from late 2009 to mid-2010 suggested that a central EUV source drives the variability of the first GLQ, so EUV flares originated in the immediate vicinity of the black hole are thermally reprocessed in the AD at 20−30 Schwarzschild radii from the dark object 10 (Gil-Merino et al 2012;Goicoechea et al 2012). Interpreting the reverberationbased size of the 2600 Å source as a flux-weighted emitting radius (e.g.…”

Section: Quasar Accretion Flowsmentioning

confidence: 99%

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New database for a sample of optically bright lensed quasars in the northern hemisphere

Gil-Merino

Goicoechea

Shalyapin

et al. 2018

A&A

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In the framework of the Gravitational LENses and DArk MAtter (GLENDAMA) project, we present a database of nine gravitationally lensed quasars (GLQs) that have two or four images brighter than r = 20 mag and are located in the northern hemisphere. This new database consists of a rich variety of follow-up observations included in the GLENDAMA global archive, which is publicly available online and contains 6557 processed astronomical frames of the nine lens systems over the period 1999−2016. In addition to the GLQs, our archive also incorporates binary quasars, accretion-dominated radio-loud quasars, and other objects, where about 50% of the non-GLQs were observed as part of a campaign to identify GLQ candidates. Most observations of GLQs correspond to an ongoing long-term macro-programme with 2−10 m telescopes at the Roque de los Muchachos Observatory, and these data provide information on the distribution of dark matter at all scales. We outline some previous results from the database, and we additionally obtain new results for several GLQs that update the potential of the tool for astrophysical studies.

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“…Kochanek 2004;Eigenbrod et al 2008;Poindexter, Morgan & Kochanek 2008;Dai et al 2010;Morgan et al 2010Morgan et al , 2012Hainline et al 2013;Mosquera et al 2013;Blackburne et al 2014;MacLeod et al 2015). Multiwavelength intrinsic variability of GLQ images also produces valuable reverberation maps of emitting regions of quasars (Gil-Merino et al 2012;Goicoechea et al 2012), which will become in critical tools to check microlensing-derived source structures.…”

Section: Introductionmentioning

confidence: 99%

Discovery of the optically bright, wide separation double quasar SDSS J1442+4055

Sergeyev¹,

Zheleznyak²,

Shalyapin³

et al. 2015

Mon. Not. R. Astron. Soc.

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Optically bright, wide separation double (gravitationally lensed) quasars can be easily monitored, leading to light curves of great importance in determining the Hubble constant and other cosmological parameters, as well as the structure of active nuclei and halos of galaxies. Searching for new double quasars in the SDSS-III database, we discovered SDSS J1442+4055. This consists of two bright images (r ∼ 18−19) of the same distant quasar at z = 2.575. The two quasar images are separated by ∼ 2. 1, show significant parallel flux variations and can be monitored from late 2015. We also found other two double quasar candidates, SDSS J1617+3827 (z = 2.079) and SDSS J1642+3200 (z = 2.264), displaying evidence for the presence of a lensing object and parallel flux variations, but requiring further spectroscopic observations to be confirmed as lensed quasars.

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Continuum reverberation mapping in az= 1.41 radio-loud quasar

Cited by 3 publications

References 13 publications

Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability

Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability

New database for a sample of optically bright lensed quasars in the northern hemisphere

Discovery of the optically bright, wide separation double quasar SDSS J1442+4055

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