S. Frederick, E. Kara, C. Reynolds, C. Pinto, A. Fabian
{"title":"X-Ray Reverberation Mapping and Dramatic Variability of Seyfert 1 Galaxy 1H 1934-063","authors":"S. Frederick, E. Kara, C. Reynolds, C. Pinto, A. Fabian","doi":"10.3847/1538-4357/aae306","DOIUrl":"https://doi.org/10.3847/1538-4357/aae306","url":null,"abstract":"A fraction of active galactic nuclei (AGN) exhibit dramatic variability, which is observed on timescales down to minutes in the X-ray band. We introduce the case study of 1H 1934-063 (z = 0.0102), a Narrow-line Seyfert 1 among the brightest and most variable AGN ever observed with XMM-Newton. This work includes spectral and temporal analyses of a concurrent XMM-Newton and NuSTAR 2015 observation lasting 130 kiloseconds, during which the X-ray source exhibited a steep (factor of ∼6) plummet and subsequent full recovery of the flux level, accompanied by deviation from a single log-normal flux distribution. We rule out Compton-thin obscuration as the cause for this dramatic variability observed even at NuSTAR energies. In order to constrain coronal geometry, dynamics, and emission/absorption processes, we compare a detailed spectral fitting with a Fourier-based timing analysis. Similar to other well-studied, highly variable Seyfert 1s, this AGN is X-ray bright and displays strong reflection features. We find a narrower broad iron line component compared to most Seyfert 1s, and constrain the black hole spin to be <0.1, one of the lowest yet discovered for such systems. Combined spectral and timing results are consistent with a dramatic change in the continuum on timescales as short as a few kiloseconds dictating the nature of this variability. We also discover a Fe–K time lag, measuring a delay of 20 s between relativistically blurred reflection off the inner accretion flow and the hard X-ray continuum emission.","PeriodicalId":107180,"journal":{"name":"Th0e Astrophysical Journal","volume":"05 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129656265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}