Time Delay of Mg ii Emission Response for the Luminous Quasar HE 0435-4312: toward Application of the High-accretor Radius–Luminosity Relation in Cosmology

Abstract

Using six years of spectroscopic monitoring of the luminous quasar HE 0435-4312 (z = 1.2231) with the Southern African Large Telescope, in combination with photometric data (CATALINA, OGLE, SALTICAM, and BMT), we determined a rest-frame time delay of days between the Mg ii broad-line emission and the ionizing continuum using seven different time-delay inference methods. Time-delay artifact peaks and aliases were mitigated using the bootstrap method and prior weighting probability function, as well as by analyzing unevenly sampled mock light curves. The Mg ii emission is considerably variable with a fractional variability of ∼5.4%, which is comparable to the continuum variability (∼4.8%). Because of its high luminosity (L 3000 = 1046.4 erg s−1), the source is beneficial for a further reduction of the scatter along the Mg ii-based radius–luminosity relation and its extended versions, especially when the highly accreting subsample that has an rms scatter of ∼0.2 dex is considered. This opens up the possibility of using the high-accretor Mg ii-based radius–luminosity relation for constraining cosmological parameters. With the current sample of 27 reverberation-mapped sources, the best-fit cosmological parameters (Ωm, ΩΛ) = (0.19; 0.62) are consistent with the standard cosmological model within the 1σ confidence level.

Standardizing reverberation-measured Mg II time-lag quasars, by using the radius-luminosity relation, and constraining cosmological model parameters

“…the higher the acrretion rate, the larger the departure. The same trend was later confirmed for the Mg II QSO 𝑅 − 𝐿 relation (Zajaček et al 2020;Martínez-Aldama et al 2020b;Zajaček et al 2021).…”

“…This sample includes the first 69 QSOs listed in Table A1. These data are described in detail in Martínez-Aldama et al (2020b) and Zajaček et al (2021). This quasar sample contains 69 QSOs including those from the most recent Mg II Sloan Digital Sky Survey Reverberation Mapping data set (SDSS-RM, 57 sources; Homayouni et al 2020), from previous SDSS-RM results (6 sources; Shen et al 2016, where one source is included in the more 5 Recent observational constraints on the 𝜙CDM model are discussed in Avsajanishvili et al (2015), Solà Peracaula et al (2018Peracaula et al ( , 2019, Zhai et al (2017), Ooba et al (2018bOoba et al ( , 2019, Park & Ratra (2018, 2019b, Sangwan et al (2018), Singh et al (2019), Ureña-López & Roy (2020), Sinha & Banerjee (2021), and references therein.…”

“…We refer to these reverberation-mapped sources as Mg II QSOs. We use Mg II QSOs to constrain cosmological dark energy models for the following reasons: (i) The current reasonably large number, 78, of studied Mg II QSOs at intermediate 𝑧 (Czerny et al 2019;Homayouni et al 2020;Martínez-Aldama et al 2020b;Zajaček et al 2020Zajaček et al , 2021Yu et al 2021). The current Mg II QSO redshift range 0.0033 ≤ 𝑧 ≤ 1.89 is more extended, especially towards higher redshifts, than that of 117 reverberation-mapped H𝛽 quasars (0.002 ≤ 𝑧 ≤ 0.89; Martínez-Aldama et al 2019).…”

“…The 𝑅 − 𝐿 correlation, although with a relatively large dispersion of ∼ 0.3 dex for Mg II QSOs (Martínez-Aldama et al 2020b;Zajaček et al 2021), in principle enables us to use reverberationmeasured Mg II QSOs to determine constraints on cosmological parameters since the time delay measurement allows one to obtain the source absolute luminosity (see Panda et al 2019;Martinez Aldama et al 2020a, for overviews). Some attempts have previously been made to use reverberation-measured QSOs in cosmology (Martínez-Aldama et al 2019;Czerny et al 2021;Zajaček et al 2021), and so far an overall agreement has been found with the standard ΛCDM cosmological model for H𝛽 QSOs (Martínez-Aldama et al 2019), combined H𝛽 and Mg II sources (Czerny et al 2021), and Mg II QSOs alone (Zajaček et al 2021).…”

Cosmological constraints from H ii starburst galaxy apparent magnitude and other cosmological measurements

“…Gurvits et al 1999;Vishwakarma 2001;Lima & Alcaniz 2002;Zhu & Fujimoto 2002;Chen & Ratra 2003) with the compilation of Cao et al (2017) being a significant step forward. Other probes under development now include reverberation-measured Mg ii time-lag radiusluminosity relation QSOs that reach to z ∼ 1.9 (Martínez-Aldama et al 2019b;Czerny et al 2021;Zajaček et al 2021;Yu et al 2021;. High redshift options include QSO X-ray and UV flux measurements which extend to z ∼ 7.5 (Risaliti & Lusso 2015Khadka & Ratra 2020aYang et al 2020;Lusso et al 2020;Li et al 2021;Lian et al 2021), 3 and gamma-ray burst (GRB) data that extend to z ∼ 8.2 (Amati et al 2008(Amati et al , 2019Samushia & Ratra 2010;Wang et al 2016;Demianski et al 2021;Fana Dirirsa et al 2019;Khadka & Ratra 2020c;Wang et al 2021;Hu et al 2021).…”