| Name: | Ritesh Ghosh |
| Affiliation: | Post Doctoral Research Associate, NASA/CRESST-II/UMBC |
| Conference ID : | ASI2023_107 |
| Title : | NASA’s Swift Tracks Potential Magnetic Flip of super-massive Black Hole |
| Authors : | Sibasish Laha, Eileen Meyer, Agniva Roychowdhury, Josefa Becerra Gonzalez, J. A. Acosta–Pulido, Aditya Thapa, Ehud Behar, Luigi C. Gallo, Gerard A. Kriss, Francesca Panessa, Stefano Bianchi, Fabio La Franca, Nicolas Scepi, Mitchell C. Begelman, Anna Lia Longinotti, Elisabeta Lusso, Samantha Oates, Matt Nicholl, and S. Bradley Cenko |
| Mode of Presentation: | Oral |
| Abstract Category : | Extragalactic Astronomy |
| Abstract : | Changing-look AGNs are a new sub-class of AGNs that show dramatic changes in their spectra in a year’s timescale. This dramatic change in the form of the appearance or disappearance of broad Balmer emission lines within months-years challenges our understanding of the AGN unified model. This behavior is often associated with changes in the accretion rate and optical/X-ray spectral state of the AGN. 1ES~1927+654 is a unique changing look active galactic nucleus (CL-AGN) which has recently gone through some dramatic changes in optical-UV, X-ray, and radio emission. In this work, we report the evolution of the radio, optical, UV, and X-rays from the pre-flare state through mid-2021 with new and archival data from the Neil Gehrels Swift Observatory, XMM-Newton, Very Long Baseline Array, the Very Large Array, Gran Telescopio Canaris, and Galileo National Telescope. The main results from our work are: 1) The source has returned to its pre-flare state in optical, UV, and X-ray; the disk--corona relation has been re-established. 2) The X-rays vanished for several months and then again resurfaced, while the UV luminosity from the accretion disk continued to fall monotonically as a power law t^(-0.91). This slope is shallower compared to tidal disruption events (t^{-5/3). We conjecture that a magnetic flux inversion event is the cause of this enigmatic event. 3)There is no correlation between the UV and X-rays at any time during the changing look phase. 4). The compact radio emission at spatial scales <1pc was at its lowest level during the changing look event in 2018, contemporaneous with the vanishing of the power law component, indicating that the core radio emission from the source originated from the corona. Our work resulted in a NASA press release on 5th May 2022, with the following web-link:
https://www.nasa.gov/feature/goddard/2022/nasa-s-swift-tracks-potential-magnetic-flip-of-monster-black-hole
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