A4 Refereed article in a conference publication
Long term multi-wavelength analysis of the Flat Spectrum Radio Quasar OP 313
Authors: Bartolini, Chiara; Lindfors, Elina; Giroletti, Marcello; Tramacere, Andrea; Giacchino, Federica; Casaburo, Fausto; Cerasole, Davide; Myserlis, Ioannis; Lähteenmäki, Anne; Tornikoski, Merja; D'Ammando, Filippo; Marchili, Nicola; Righini, Simona; Angelakis, Emmanouil; Kraus, Alexander; Rao, Ramprasad; Agudo, Ivan; Gurwell, Mark A.; Keating, Garrett; Marscher, Alan; Jorstad, Svetlana G.; Bissaldi, Elisabetta; Di Venere, Leonardo; Giordano, Francesco; Loporchio, Serena
Editors: N/A
Conference name: International Cosmic Ray Conference
Publisher: Sissa Medialab
Publication year: 2025
Journal: POS Proceedings of Science
Book title : Proceedings of 39th International Cosmic Ray Conference (ICRC2025)
Article number: 565
Volume: 501
eISSN: 1824-8039
DOI: https://doi.org/10.22323/1.501.0565
Publication's open availability at the time of reporting: Open Access
Publication channel's open availability : Open Access publication channel
Web address : https://doi.org/10.22323/1.501.0565
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/508978675
Self-archived copy's licence: CC BY NC ND
Self-archived copy's version: Publisher`s PDF
The Flat Spectrum Radio Quasar OP 313 is a high-redshift blazar that was characterized by intense γ-ray emission starting from November 2023 to March 2024, as observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi). We present a multi-wavelength analysis covering 15 years of Fermi-LAT observations, from August 2008 to March 2024, to understand the mechanisms involved in particle acceleration inside the jet of this galaxy, and how emitted radiation in different wavelengths is connected. We analyzed a large sample of datasets coming from different facilities and projects to look at the trend in the multi-wavelength light-curves. From these, we identified the 7 most intense γ-ray flaring periods, and we analyzed each of them to unveil the responsible physical mechanisms. We realized for each of them the photon index versus flux plot in order to identify potential hysteresis patterns, and then, a kinematic study of the VLBA dataset was pursued to see if new knots arose in the jet before or during the 7 flaring periods we see. Finally, we performed an SED modeling for 2 of the 7 flaring periods. From the SED modeling, we found that a photon field coming from the dusty torus outside the jet is responsible for the γ-ray emission we saw starting from November 2023.
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Funding information in the publication:
This proceeding and related research have been conducted during and with the support of the Italian national inter-university PhD program in Space Science and Technology. F.G.: acknowledges financial support from Junta de Castilla y Le\u00F3n project SA101P24. The Fermi-LAT Collaboration acknowledges support for LAT development, operation and data analysis from NASA and DOE (United States), CEA/Irfu and IN2P3/CNRS (France), ASI and INFN (Italy), MEXT, KEK, and JAXA (Japan), and the K.A. Wallenberg Foundation, the Swedish Research Council and the National Space Board (Sweden). Science analysis support in the operations phase from INAF (Italy) and CNES (France) is also gratefully acknowledged. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d\u2019\u00C9tudes Spatiales in France. This work was performed in part under DOE Contract DE-AC02-76SF00515. This research has made use of the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. This publication makes use of data obtained at Mets\u00E4hovi Radio Observatory, operated by Aalto University in Finland. This publication makes use of data based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut f\u00FCr Radioastronomie). I.M., I.N. and V.K. were funded by the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne. This research has made use of data from the MOJAVE database that is maintained by the MOJAVE team [16]. This study makes use of VLBA data from the VLBA-BU Blazar Monitoring Program (BEAM-ME and VLBA-BU-BLAZAR; http://www.bu.edu/blazars/BEAM-ME.html), funded by NASA through the Fermi Guest Investigator Program. This research has made use of data from the MOJAVE database that is maintained by the MOJAVE team [16]. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. Maunakea, the location of the SMA, is a culturally important site for the indigenous Hawaiian people; we are privileged to study the cosmos from its summit.
