Spectral optical monitoring of a double-peaked emission line AGN Arp 102B

Abstract

Context. We present results of long-term (1987-2010) optical spectral monitoring of the broad-line radio galaxy Arp 102B, a prototype of an active galactic nucleus with double-peaked broad emission lines that are commonly assumed to be emitted from an accretion disk. Aims. To explore the structure of the broad-line region (BLR), we analyze the light-curves of the broad Hα and Hβ lines and the continuum flux. We aim to estimate the dimensions of the broad-line emitting regions and the mass of the central black hole. Methods. We used the cross correlation function to find lags between the lines and continuum variations. We investigated the correlation between line and continuum fluxes in more detail and explored periodical variations of the red-to-blue line flux ratio using Lomb-Scargle periodograms. Results. The line and continuum light-curves show several flare-like events. The fluxes in lines and in the continuum show no significant change (around 20%) during the monitored period. We found a weak correlation between the line and continuum flux variation that may indicate that the line variation is weakly connected with the variation of the central photoionization source. In spite of this weak line-continuum correlation, we estimated a time lag for Hβ of about 20 days using various methods. The correlation between the Hβ and Hα flux variation is significantly higher than that between the lines and continuum. During the monitored period, the Hβ and Hα lines show double-peaked profiles, and we found an indication for a periodical oscillation in the red-to-blue flux ratio of the Hα line. The estimated mass of the central black hole is ∼1.1 × 10 8 M , which agrees with the mass estimated from the M-σ * relation.

Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

“…All spectral data for each objects have been first presented and analyzed separately in Shapovalova et al (2001Shapovalova et al ( , 2004Shapovalova et al ( , 2008Shapovalova et al ( , 2010aShapovalova et al ( , 2012Shapovalova et al ( , 2013Shapovalova et al ( , 2016Shapovalova et al ( , 2017. However, since the obtained spectra are observed, reduced and analyzed in the same manner, the final result is a uniform set of data, which can be compared and discussed.…”

SALT long-slit spectroscopy of quasar HE 0435-4312: fast displacement of the Mg II emission line

“…Intrinsic variations of the emission line profile (i.e., not just the line intensity) have been measured for a few sources, almost always for Balmer lines (e.g., NGC 4151: Shapovalova et al 2008, 2010a, 3C 390.3: Gaskell 1996, Shapovalova et al 2010b; Arp 102B: Shapovalova et al 2013, Popovic et al 2014; Ark 564: Shapovalova et al 2012;NGC 1097: Storchi-Bergmann et al 1995, Schimoia et al 2015NGC 5548: Peterson et al 1987, Shapovalova et al 2004, Sergeev et al 2007, Bon et al 2016; see Ilic et al 2015 for a campaign summary). Variability of the Mg II and C IV line wings was explored by Punsly (2013), but in this case part of the emission is related to the radio jet mechanism.…”

Line Shape Variability in a Sample of AGN with Broad Lines

“…It is assumed that the BLR gas is photoionized by the continuum coming from the central source, and that is gravitationally bound Shapovalova et al (2013Shapovalova et al ( ) (1987Shapovalova et al ( -2013 15900/14300…”