Changing looks of the nucleus of Seyfert galaxy NGC 3516 during 2016-2020

TL;DR

This study presents spectral observations of NGC 3516 from 2016 to 2020, revealing multiple changes in its spectral type and broad emission line strength, indicating variable activity states of the galaxy's nucleus.

Contribution

It provides a detailed observational record of the changing spectral states of NGC 3516 over several years, highlighting variability in its broad emission lines.

Findings

Detected spectral type change in 2016 with broad Hbeta component

Observed weakening and strengthening of Hbeta over years

Documented multiple changing looks of NGC 3516 during 2016-2020

Abstract

The results of spectral observations of NGC 3516 with the 2-m telescope of the Shamakhy Astrophysical Observatory during 2016-2020 are presented. In the first half of 2016, the intensive broad component Hbeta was found, which indicates a spectral type change compared to 2014, when the broad component was almost invisible. In the second half of 2016, the broad component H${\beta}$ again was weakened and was practically not observed, remaining as weak until the end of 2019. At the end of 2019, the broad component Hbeta strengthened again, and in May 2020 reached a typical level for the high state of the object. During 2016-2020 we observed several changing looks of NGC 3516.