A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states

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dc.contributor.authorLaha, Sibasish
dc.contributor.authorMeyer, Eileen
dc.contributor.authorRoychowdhury, Agniva
dc.contributor.authorBecerra, Josefa G.
dc.contributor.authorAcosta-Pulido, J. A.
dc.contributor.authorThapa, Aditya
dc.contributor.authorGhosh, Ritesh
dc.contributor.authorBehar, Ehud
dc.contributor.authorGallo, Luigi C.
dc.contributor.authorKriss, Gerard A.
dc.contributor.authorPanessa, Francesca
dc.contributor.authorBianchi, Stefano
dc.contributor.authorLa Franca, Fabio
dc.contributor.authorScepi, Nicolas
dc.contributor.authorBegelman, Mitchell C.
dc.contributor.authorLonginotti, Anna Lia
dc.contributor.authorLusso, Elisabeta
dc.contributor.authorOates, Samantha
dc.contributor.authorNicholl, Matt
dc.contributor.authorCenko, S. Bradley
dc.date.accessioned2022-04-13T13:21:32Z
dc.date.available2022-04-13T13:21:32Z
dc.date.issued2022-03-16
dc.description.abstractThe nearby type-II AGN 1ES1927+654 went through a violent changing-look (CL) event beginning December 2017 during which the optical and UV fluxes increased by four magnitudes over a few months, and broad emission lines newly appeared in the optical/UV. By July 2018 the X-ray coronal emission had completely vanished, only to reappear a few months later. 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 Very Long Baseline Array (VLBA), the European VLBI Network, the Very Large Array (VLA), the Telescopio Nazionale Galileo (TNG), Gran Telescopio Canarias (GTC), The Neil Gehrels Swift observatory and XMM-Newton. The main results from our work are: (1) The source has returned to its pre-CL state in optical, UV, and X-ray; the disk-corona relation has been re-established as has been in the pre-CL state, with an αₒₓ∼1.02. The optical spectra are dominated by narrow emission lines. (2) The UV light curve follows a shallower slope of ∝t⁻⁰·⁹¹±⁰·⁰⁴ compared to that predicted by a tidal disruption event. We conjecture that a magnetic flux inversion event is the possible cause for this enigmatic event. (3) The compact radio emission which we tracked in the pre-CL (2014), during CL (2018) and post-CL(2021) at spatial scales <1 pc was at its lowest level during the changing look event in 2018, nearly contemporaneous with a low 2−10 keV emission. The radio to X-ray ratio of the compact source LRadio/LX−ray∼10⁻⁵·⁵, follows the Gudel-Benz relation, typically found in coronally active stars, and several AGN. (4) We do not detect any presence of nascent jets at the spatial scales of ∼5−10 pc.en_US
dc.description.sponsorshipThe authors acknowledge useful discussions with A. Vazdekis. The material is based upon work supported by NASA under award number 80GSFC21M0002. JBG and JAP acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) through the Spanish State Research Agency, under Severo Ochoa Program 2020-2023 (CEX2019-000920- S). SB acknowledges financial support from the Italian Space Agency (grant 2017-12-H.0). SL is thankful to the Swift team for granting the director’s discretionary time to observe the source at a regular cadence. SL is thankful to Jay Friedlander who has created the graphics of the magnetic flux inversion event (Fig 9). MN is supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 948381) and by a Fellowship from the Alan Turing Institute. E.B. acknowledges support by a Center of Excellence of THE ISRAEL SCIENCE FOUNDATION (grant No. 2752/19).en_US
dc.description.urihttps://arxiv.org/abs/2203.07446en_US
dc.format.extent31 pagesen_US
dc.genrejournal articlesen_US
dc.genrepreprintsen_US
dc.identifierdoi:10.13016/m2t7wp-iqjz
dc.identifier.issnhttps://doi.org/10.48550/arXiv.2203.07446
dc.identifier.urihttp://hdl.handle.net/11603/24539
dc.language.isoen_USen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Center for Space Sciences and Technology
dc.relation.ispartofUMBC Faculty Collection
dc.relation.ispartofUMBC Physics Department
dc.relation.ispartofUMBC Joint Center for Earth Systems Technology (JCET)
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.en_US
dc.rightsAttribution 4.0 International (CC BY 4.0)*
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/*
dc.titleA radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare statesen_US
dc.typeTexten_US
dcterms.creatorhttps://orcid.org/0000-0003-2714-0487en_US
dcterms.creatorhttps://orcid.org/0000-0002-7676-9962en_US
dcterms.creatorhttps://orcid.org/0000-0003-1101-8436en_US
dcterms.creatorhttps://orcid.org/0000-0002-8843-9581en_US
dcterms.creatorhttps://orcid.org/0000-0003-1673-970Xen_US

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