The performance of photometric reverberation mapping at high redshift and the reliability of damped random walk models

Read, Shaun C.; Smith, D. J. B.; Jarvis, Matt J.; Gürkan, G.

doi:10.1093/mnras/stz3574

Cited by 3 publications

(2 citation statements)

References 99 publications

(202 reference statements)

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“…Antonucci 1993;Lacy et al 2004;Martínez-Sansigre et al 2005), since accretion processes are variable (e.g. Read et al 2020) and since AGN are highly multimodal (e.g. Hardcastle et al 2007;Best & Heckman 2012).…”

Section: Introductionmentioning

confidence: 99%

The LOFAR Two-metre Sky Survey Deep Fields

Smith

Haskell

Gürkan

et al. 2021

A&A

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In this paper, we investigate the relationship between 150 MHz luminosity and the star-formation rate – the SFR-L150 MHz relation – using 150 MHz measurements for a near-infrared selected sample of 118 517 z < 1 galaxies. New radio survey data offer compelling advantages over previous generation surveys for studying star formation in galaxies, including huge increases in sensitivity, survey speed, and resolution, while remaining impervious to extinction. The LOFAR Surveys Key Science Project is transforming our understanding of the low-frequency radio sky, with the 150 MHz data over the European Large Area Infrared Space Observatory Survey-North 1 field reaching an rms sensitivity of 20 μJy beam−1 over 10 deg2 at 6 arcsec resolution. All of the galaxies studied have SFR and stellar mass estimates that were derived from energy balance spectral energy distribution fitting using redshifts and aperture-matched forced photometry from the LOFAR Two-metre Sky Survey (LoTSS) Deep Fields data release. The impact of active galactic nuclei (AGN) is minimised by leveraging the deep ancillary data in the LoTSS data release, alongside median-likelihood methods that we demonstrate are resistant to AGN contamination. We find a linear and non-evolving SFR-L150 MHz relation, apparently consistent with expectations based on calorimetric arguments, down to the lowest SFRs < 0.01M⊙ yr−1. However, we also recover compelling evidence for stellar mass dependence in line with previous work on this topic, in the sense that higher mass galaxies have a larger 150 MHz luminosity at a given SFR, suggesting that the overall agreement with calorimetric arguments may be a coincidence. We conclude that, in the absence of AGN, 150 MHz observations can be used to measure accurate galaxy SFRs out to z = 1 at least, but it is necessary to account for stellar mass in the estimation in order to obtain 150 MHz-derived SFRs accurate to better than 0.5 dex. Our best-fit relation is log10(L150 MHz ∕W Hz−1) = (0.90 ± 0.01)log10(ψ∕M⊙ yr−1) + (0.33 ± 0.04)log10(M∕1010M⊙) + 22.22 ± 0.02.

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Section: Introductionmentioning

confidence: 99%

The LOFAR Two-metre Sky Survey Deep Fields

Smith

Haskell

Gürkan

et al. 2021

A&A

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“…Similar to CREAM, JAVELIN (Zu et al 2011) uses a damped random walk (DRW) model to describe the stochastic variability of the quasar lightcurves. Even though the DRW model may be an incomplete description for quasars on short timescales (Mushotzky et al 2011;Kozłowski 2016), studies have shown that the DRW model still provides a flexible approach to accurately measuring lags (Li et al 2019;Read et al 2020) and a reasonable fit to observations of quasar variability on the timescales of our monitoring program (days to weeks) (Kelly et al 2009;MacLeod et al 2010MacLeod et al , 2012Kozłowski 2016).…”

Section: Lag Identificationmentioning

confidence: 99%

The Sloan Digital Sky Survey Reverberation Mapping Project: UV–Optical Accretion Disk Measurements with the Hubble Space Telescope

Homayouni

Sturm

Trump

et al. 2022

ApJ

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We present accretion-disk structure measurements from UV–optical reverberation mapping (RM) observations of a sample of eight quasars at 0.24 < z < 0.85. Ultraviolet photometry comes from two cycles of Hubble Space Telescope monitoring, accompanied by multiband optical monitoring by the Las Cumbres Observatory network and Liverpool Telescopes. The targets were selected from the Sloan Digital Sky Survey Reverberation Mapping project sample with reliable black hole mass measurements from Hβ RM results. We measure significant lags between the UV and various optical griz bands using JAVELIN and CREAM methods. We use the significant lag results from both methods to fit the accretion-disk structure using a Markov Chain Monte Carlo approach. We study the accretion disk as a function of disk normalization, temperature scaling, and efficiency. We find direct evidence for diffuse nebular emission from Balmer and Fe ii lines over discrete wavelength ranges. We also find that our best-fit disk color profile is broadly consistent with the Shakura & Sunyaev disk model. We compare our UV–optical lags to the disk sizes inferred from optical–optical lags of the same quasars and find that our results are consistent with these quasars being drawn from a limited high-lag subset of the broader population. Our results are therefore broadly consistent with models that suggest longer disk lags in a subset of quasars, for example, due to a nonzero size of the ionizing corona and/or magnetic heating contributing to the disk response.

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Modelling photometric reverberation mapping data for the next generation of big data surveys. Quasar accretion discs sizes with the LSST

Núñez

Bruckmann

Desamutara

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Photometric reverberation mapping can detect the radial extent of the accretion disc (AD) in Active Galactic Nuclei by measuring the time delays between light curves observed in different continuum bands. Quantifying the constraints on the efficiency and accuracy of the delay measurements is important for recovering the AD size-luminosity relation, and potentially using quasars as standard candles. We have explored the possibility of determining the AD size of quasars using next-generation Big Data surveys. We focus on the Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory, which will observe several thousand quasars with the Deep Drilling Fields and up to 10 million quasars for the main survey in six broadband filter during its 10-year operational lifetime. We have developed extensive simulations that take into account the characteristics of the LSST survey and the intrinsic properties of the quasars. The simulations are used to characterise the light curves from which AD sizes are determined using various algorithms. We find that the time delays can be recovered with an accuracy of 5 and 15% for light curves with a time sampling of 2 and 5 days, respectively. The results depend strongly on the redshift of the source and the relative contribution of the emission lines to the bandpasses. Assuming an optically thick and geometrically thin AD, the recovered time-delay spectrum is consistent with black hole masses derived with 30% uncertainty.

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The performance of photometric reverberation mapping at high redshift and the reliability of damped random walk models

Cited by 3 publications

References 99 publications

The LOFAR Two-metre Sky Survey Deep Fields

The LOFAR Two-metre Sky Survey Deep Fields

The Sloan Digital Sky Survey Reverberation Mapping Project: UV–Optical Accretion Disk Measurements with the Hubble Space Telescope

Modelling photometric reverberation mapping data for the next generation of big data surveys. Quasar accretion discs sizes with the LSST

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