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Long-term multiwavelength monitoring and reverberation mapping of NGC 2617 during a changing-look event.
- Source :
- Monthly Notices of the Royal Astronomical Society; 10/20/2023, Vol. 525 Issue 2, p2571-2584, 14p
- Publication Year :
- 2023
-
Abstract
- We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 2617 carried out from 2016 until 2022 and covering the wavelength range from the X-ray to the near-IR. The facilities included the telescopes of the SAI MSU, MASTER Global Robotic Net, the 2.3-m WIRO telescope, Swift , and others. We found significant variability at all wavelengths and, specifically, in the intensities and profiles of the broad Balmer lines. We measured time delays of ∼6 d (∼8 d) in the responses of the Hβ (Hα) line to continuum variations. We found the X-ray variations to correlate well with the UV and optical (with a small time delay of a few days for longer wavelengths). The K -band lagged the B band by 14 ± 4 d during the last three seasons, which is significantly shorter than the delays reported previously by the 2016 and 2017–2019 campaigns. Near-IR variability arises from two different emission regions: the outer part of the accretion disc and a more distant dust component. The HK -band variability is governed primarily by dust. The Balmer decrement of the broad-line components is inversely correlated with the UV flux. The change of the object's type from Sy1 to Sy1.8 was recorded over a period of ∼8 yr. We interpret these changes as a combination of two factors: changes in the accretion rate and dust recovery along the line of sight. [ABSTRACT FROM AUTHOR]
- Subjects :
- ACCRETION disks
ACCRETION (Astrophysics)
DUST
Subjects
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 525
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 171877256
- Full Text :
- https://doi.org/10.1093/mnras/stad2442