AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus
AT 2019aalc is a peculiar sequence of highly variable emission events observed towards the nucleus of the broad-line active galactic nucleus (AGN) SDSS J152416.66+045119.0. The system exhibited two distinct UV-optical flares (the first detected in 2019, the second one in 2023). Spectra obtained foll...
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| Format: | Article |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/aded13 |
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| author | Marzena Śniegowska Benny Trakhtenbrot Lydia Makrygianni Iair Arcavi Claudio Ricci Sara Faris Biswaraj Palit D. Andrew Howell Megan Newsome Joseph Farah Curtis McCully Estefania Padilla-Gonzalez Giacomo Terreran |
| author_facet | Marzena Śniegowska Benny Trakhtenbrot Lydia Makrygianni Iair Arcavi Claudio Ricci Sara Faris Biswaraj Palit D. Andrew Howell Megan Newsome Joseph Farah Curtis McCully Estefania Padilla-Gonzalez Giacomo Terreran |
| author_sort | Marzena Śniegowska |
| collection | DOAJ |
| description | AT 2019aalc is a peculiar sequence of highly variable emission events observed towards the nucleus of the broad-line active galactic nucleus (AGN) SDSS J152416.66+045119.0. The system exhibited two distinct UV-optical flares (the first detected in 2019, the second one in 2023). Spectra obtained following the detection of the second flare revealed prominent Bowen fluorescence (BF) and high-ionization coronal emission lines, which were much weaker, if at all detectable, in a spectrum taken following the first flare. We present and analyze a large set of multi-wavelength, multi-epoch data for this source, with particular emphasis on optical spectroscopic monitoring conducted with the Las Cumbres Observatory network. During the relatively slow dimming that followed the second optical flare, the UV-optical light curve shows a sequence of minor rebrightening events, while the BF and the coronal lines vary (roughly) in tandem with these “bumps” in the broadband light curve. Most of the observed behavior of AT 2019aalc links it to the growing class of BF flares while setting it apart from canonical tidal disruption events. However, AT 2019aalc has some outstanding peculiarities, including two short flares seen in its soft X-ray light-curve during the dimming phase of the second optical flare, and which do not seem to be linked to the emission line variations. We discuss the optical and X-ray properties of the source and possible scenarios of the origin of the flare, in particular radiation pressure instabilities in the (preexisting) AGN accretion disk. |
| format | Article |
| id | doaj-art-57df84e8e05e467f93f77de8d4f25b9a |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-57df84e8e05e467f93f77de8d4f25b9a2025-08-20T03:36:26ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01989217310.3847/1538-4357/aded13AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic NucleusMarzena Śniegowska0https://orcid.org/0000-0003-2656-6726Benny Trakhtenbrot1https://orcid.org/0000-0002-3683-7297Lydia Makrygianni2https://orcid.org/0000-0002-7466-4868Iair Arcavi3https://orcid.org/0000-0001-7090-4898Claudio Ricci4https://orcid.org/0000-0001-5231-2645Sara Faris5https://orcid.org/0009-0007-8485-1281Biswaraj Palit6https://orcid.org/0000-0002-4533-3170D. Andrew Howell7https://orcid.org/0000-0003-4253-656XMegan Newsome8https://orcid.org/0000-0001-9570-0584Joseph Farah9https://orcid.org/0000-0003-4914-5625Curtis McCully10https://orcid.org/0000-0001-5807-7893Estefania Padilla-Gonzalez11https://orcid.org/0000-0003-0209-9246Giacomo Terreran12https://orcid.org/0000-0003-0794-5982School of Physics and Astronomy, Tel Aviv University , Tel Aviv 69978, Israel ; marzena.sniegowska@gmail.comSchool of Physics and Astronomy, Tel Aviv University , Tel Aviv 69978, Israel ; marzena.sniegowska@gmail.com; Max-Planck-Institut für extraterrestrische Physik , Gießenbachstraße 1, 85748 Garching, Germany; Excellence Cluster ORIGINS , Boltzmannsstraße 2, 85748 Garching, GermanyDepartment of Physics, Lancaster University , Lancaster LA1 4YB, UKSchool of Physics and Astronomy, Tel Aviv University , Tel Aviv 69978, Israel ; marzena.sniegowska@gmail.com; CIFAR Azrieli Global Scholars Program , CIFAR, Toronto, CanadaInstituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales , Av. Ejército Libertador 441, Santiago, Chile; Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People’s Republic of ChinaSchool of Physics and Astronomy, Tel Aviv University , Tel Aviv 69978, Israel ; marzena.sniegowska@gmail.comNicolaus Copernicus Astronomical Center , Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, PolandLas Cumbres Observatory , 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USA; Department of Physics, University of California , Santa Barbara, CA 93106-9530, USALas Cumbres Observatory , 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USA; Department of Physics, University of California , Santa Barbara, CA 93106-9530, USALas Cumbres Observatory , 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USA; Department of Physics, University of California , Santa Barbara, CA 93106-9530, USALas Cumbres Observatory , 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USALas Cumbres Observatory , 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USA; Department of Physics, University of California , Santa Barbara, CA 93106-9530, USALas Cumbres Observatory , 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USAAT 2019aalc is a peculiar sequence of highly variable emission events observed towards the nucleus of the broad-line active galactic nucleus (AGN) SDSS J152416.66+045119.0. The system exhibited two distinct UV-optical flares (the first detected in 2019, the second one in 2023). Spectra obtained following the detection of the second flare revealed prominent Bowen fluorescence (BF) and high-ionization coronal emission lines, which were much weaker, if at all detectable, in a spectrum taken following the first flare. We present and analyze a large set of multi-wavelength, multi-epoch data for this source, with particular emphasis on optical spectroscopic monitoring conducted with the Las Cumbres Observatory network. During the relatively slow dimming that followed the second optical flare, the UV-optical light curve shows a sequence of minor rebrightening events, while the BF and the coronal lines vary (roughly) in tandem with these “bumps” in the broadband light curve. Most of the observed behavior of AT 2019aalc links it to the growing class of BF flares while setting it apart from canonical tidal disruption events. However, AT 2019aalc has some outstanding peculiarities, including two short flares seen in its soft X-ray light-curve during the dimming phase of the second optical flare, and which do not seem to be linked to the emission line variations. We discuss the optical and X-ray properties of the source and possible scenarios of the origin of the flare, in particular radiation pressure instabilities in the (preexisting) AGN accretion disk.https://doi.org/10.3847/1538-4357/aded13AccretionTransient sourcesTime domain astronomyActive galactic nuclei |
| spellingShingle | Marzena Śniegowska Benny Trakhtenbrot Lydia Makrygianni Iair Arcavi Claudio Ricci Sara Faris Biswaraj Palit D. Andrew Howell Megan Newsome Joseph Farah Curtis McCully Estefania Padilla-Gonzalez Giacomo Terreran AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus The Astrophysical Journal Accretion Transient sources Time domain astronomy Active galactic nuclei |
| title | AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus |
| title_full | AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus |
| title_fullStr | AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus |
| title_full_unstemmed | AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus |
| title_short | AT 2019aalc: A Bowen Fluorescence Flare with a Precursor Flare in an Active Galactic Nucleus |
| title_sort | at 2019aalc a bowen fluorescence flare with a precursor flare in an active galactic nucleus |
| topic | Accretion Transient sources Time domain astronomy Active galactic nuclei |
| url | https://doi.org/10.3847/1538-4357/aded13 |
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