dc.contributor.author | Masterson, Megan | |
dc.contributor.author | Kara, Erin | |
dc.contributor.author | Pasham, Dheeraj R. | |
dc.contributor.author | D’Orazio, Daniel J. | |
dc.contributor.author | Walton, Dominic J. | |
dc.contributor.author | Fabian, Andrew C. | |
dc.contributor.author | Lucchini, Matteo | |
dc.contributor.author | Remillard, Ronald A. | |
dc.contributor.author | Arzoumanian, Zaven | |
dc.contributor.author | Burkhonov, Otabek | |
dc.contributor.author | Choi, Hyeonho | |
dc.contributor.author | Ehgamberdiev, Shuhrat A. | |
dc.contributor.author | Ferrara, Elizabeth C. | |
dc.contributor.author | Guolo, Muryel | |
dc.contributor.author | Im, Myungshin | |
dc.contributor.author | Kim, Yonggi | |
dc.contributor.author | Mirzaqulov, Davron O. | |
dc.contributor.author | Paek, Gregory S. H. | |
dc.contributor.author | Sung, Hyun-Il | |
dc.contributor.author | Yoon, Joh-Na | |
dc.date.accessioned | 2023-03-21T16:15:03Z | |
dc.date.available | 2023-03-21T16:15:03Z | |
dc.date.issued | 2023-03-14 | |
dc.identifier.citation | Masterson , M , Kara , E , Pasham , D R , D’Orazio , D J , Walton , D J , Fabian , A C , Lucchini , M , Remillard , R A , Arzoumanian , Z , Burkhonov , O , Choi , H , Ehgamberdiev , S A , Ferrara , E C , Guolo , M , Im , M , Kim , Y , Mirzaqulov , D O , Paek , G S H , Sung , H-I & Yoon , J-N 2023 , ' Unusual Hard X-Ray Flares Caught in NICER Monitoring of the Binary Supermassive Black Hole Candidate AT2019cuk/Tick Tock/SDSS J1430+2303 ' , Astrophysical Journal Letters , vol. 945 , no. 2 , L34 , pp. 1-18 . https://doi.org/10.3847/2041-8213/acbea9 | |
dc.identifier.issn | 2041-8205 | |
dc.identifier.other | Jisc: 958076 | |
dc.identifier.other | publisher-id: apjlacbea9 | |
dc.identifier.other | manuscript: acbea9 | |
dc.identifier.other | other: aas44139 | |
dc.identifier.other | ORCID: /0000-0001-5819-3552/work/131544921 | |
dc.identifier.uri | http://hdl.handle.net/2299/26129 | |
dc.description | © 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/ | |
dc.description.abstract | The nuclear transient AT2019cuk/Tick Tock/SDSS J1430+2303 has been suggested to harbor a supermassive black hole (SMBH) binary near coalescence. We report results from high-cadence NICER X-ray monitoring with multiple visits per day from 2022 January to August, as well as continued optical monitoring during the same time period. We find no evidence of periodic/quasiperiodic modulation in the X-ray, UV, or optical bands; however, we do observe exotic hard X-ray variability that is unusual for typical active galactic nuclei (AGN). The most striking feature of the NICER light curve is repetitive hard (2–4 keV) X-ray flares that result in distinctly harder X-ray spectra compared to the nonflaring data. In its nonflaring state, AT2019cuk looks like a relatively standard AGN, but it presents the first case of day-long, hard X-ray flares in a changing-look AGN. We consider a few different models for the driving mechanism of these hard X-ray flares, including (1) corona/jet variability driven by increased magnetic activity, (2) variable obscuration, and (3) self-lensing from the potential secondary SMBH. We prefer the variable corona model, as the obscuration model requires rather contrived timescales and the self-lensing model is difficult to reconcile with a lack of clear periodicity in the flares. These findings illustrate how important high-cadence X-ray monitoring is to our understanding of the rapid variability of the X-ray corona and necessitate further high-cadence, multiwavelength monitoring of changing-look AGN like AT2019cuk to probe the corona-jet connection. | en |
dc.format.extent | 18 | |
dc.format.extent | 2746174 | |
dc.language.iso | eng | |
dc.relation.ispartof | Astrophysical Journal Letters | |
dc.subject | 330 | |
dc.subject | High-Energy Phenomena and Fundamental Physics | |
dc.subject | Astronomy and Astrophysics | |
dc.subject | Space and Planetary Science | |
dc.title | Unusual Hard X-Ray Flares Caught in NICER Monitoring of the Binary Supermassive Black Hole Candidate AT2019cuk/Tick Tock/SDSS J1430+2303 | en |
dc.contributor.institution | Centre for Astrophysics Research (CAR) | |
dc.contributor.institution | Department of Physics, Astronomy and Mathematics | |
dc.contributor.institution | School of Physics, Engineering & Computer Science | |
dc.description.status | Peer reviewed | |
dc.identifier.url | http://www.scopus.com/inward/record.url?scp=85150423122&partnerID=8YFLogxK | |
rioxxterms.versionofrecord | 10.3847/2041-8213/acbea9 | |
rioxxterms.type | Journal Article/Review | |
herts.preservation.rarelyaccessed | true | |