Discovery of a new extreme changing-state quasar with 4 mag variation, SDSS J125809.31+351943.0

Abstract

We report the discovery of a quasar, SDSS J125809.31+351943.0 (J1258), which brightened in optical wavelengths for 4 mag from 1983 to 2015: one of the largest quasar brightening events so far. The history of optical photometry data of this quasar from the Catalina Real-time Transient Survey and All Sky Automated Survey for Super Novae (ASAS-SN), mid-infrared photometry data from the WISE satellite, and the broad emission line (BEL) flux obtained by spectroscopy of the Sloan Digital Sky Survey shows significant increases between 2003 and 2015. Investigating the Canada–France–Hawaii Telescope photometric observations in 1983 and the United States Naval Observatory B catalogue, which contains data from 1975 and 1969, we found that the source was 4 mag fainter before than at the peak of the recent ASAS-SN photometry. From the history of these data, we identified J1258 as a new changing-state quasar (CSQ). We also performed follow-up spectroscopic observations in 2018 December and 2019 May using the 2 m telescope at the Nishi-Harima Astronomical Observatory. The results show that the continuum flux and the BEL flux decreased to about 50% of their peak. This indicates that J1258 present two changing states for the BEL flux and continuum flux. We argue that J1258’s variability, especially its brightening event, can be explained by the propagation of the heating front and the accretion disk state transitions based on the timescale and Eddington ratio variations. The estimated mass of the black hole of J1258 is about an order of magnitude larger than the CSQs found so far. Since both the changing timescale and the size of the accretion disk depend on the black hole mass, the J1258 brightening event can be interpreted as a scaled version of the variability in other CSQs. This suggests that samples of distant quasars with larger black hole masses may contain objects with longer and more severe variations.

The Time Domain Spectroscopic Survey: Changing-look Quasar Candidates from Multi-epoch Spectroscopy in SDSS-IV

“…Yang et al (2018) found the MIR Wide-field Infrared Survey Explorer colors of CLQs are redder when brighter, indicating a strong hot dust contribution rather than reddening. In several cases, the IR tracks the optical variability (e.g., Nagoshi et al 2021), again suggesting that obscuration is not the cause of dimming in CLQs.…”

Are “Changing-look” Active Galactic Nuclei Special in the Coevolution of Supermassive Black Holes and Their Hosts? I.

“…"Changing-look" active galactic nuclei (CL-AGNs), which are AGNs with a temporary appearance or disappearance of their broad emission lines, show a spectral transition between Type 1, intermediate type, and Type 2 within a timescale of years to decades (Ricci & Trakhtenbrot 2022;Komossa & Grupe 2023). 5 The CL phenomenon is rare; thus far, with multiepoch photometry and optical spectroscopy, only ∼150 CL-AGNs have been identified (e.g., MacLeod et al 2010MacLeod et al , 2016MacLeod et al , 2019Shapovalova et al 2010;Shappee et al 2014;LaMassa et al 2015;McElroy et al 2016;Parker et al 2016;Ruan et al 2016Ruan et al , 2019Runnoe et al 2016;Gezari et al 2017;Sheng et al 2017Sheng et al , 2020Kollatschny et al 2018Kollatschny et al , 2020Mathur et al 2018;Stern et al 2018;Wang et al 2018Wang et al , 2019Wang et al , 2020aWang et al , 2022Yang et al 2018;Frederick et al 2019;Guo et al 2019;Marin et al 2019;Parker et al 2019;Trakhtenbrot et al 2019;Yan et al 2019;Ai et al 2020;Graham et al 2020;Nagoshi et al 2021;Green et al 2022;Hon et al 2020Hon et al , 2022...…”

Discovering vanishing objects in POSS I red images using the Virtual Observatory

“…Other potential types of variable objects can be found in Byrne & Fraser (2022). Moreover, extragalactic transients that can be associated to rare blazars or accretion outbursts in active galactic nuclei (Lawrence et al 2016) or highly variable quasars or microlensing events (Nagoshi et al 2021) can also contribute.…”