Blazar OJ 287 after First VHE Activity: Tracking the Reemergence of the HBL-like Component in 2020

Autor(es)

Kushwaha, Pankaj ^[1] ; Pal, Main ^[2] ; Kalita, Nibedita ^[3] ; Kumari, Neeraj ^{[4, 5]} ; Naik, Sachindra ^[5] ; Gupta, Alok C. ^{[3, 1]} ; de Gouveia Dal Pino, E. M. ^[6] ; Gu, Minfeng ^[3]

Afiliação do(s) autor(es)

^[1] Aryabhatta Res Inst Observat Sci ARIES, Naini Tal 263002 - India

^[2] Jamia Millia Islamia, Ctr Theoret Phys, New Delhi 110025 - India

^[3] Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, 80 Nandan Rd, Shanghai 200030 - Peoples R China

^[4] Indian Inst Technol, Gandhinagar 382355, Gujarat - India

^[5] Phys Res Lab, Astron & Astrophys Div, Ahmadabad 380009, Gujarat - India

^[6] Univ Sao Paulo, Dept Astron IAG USP, BR-05508090 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ASTROPHYSICAL JOURNAL; v. 921, n. 1 NOV 2021.
• Citações Web of Science: 0

Resumo

We report the reemergence of a new broadband emission through a detailed and systematic study of the multiwavelength spectral and temporal behavior of OJ 287 after its first-ever reported very high energy activity in 2017 to date, which includes the second-highest X-ray flux of the source. The source shows high optical to X-ray flux variations, accompanied mainly by strong spectral changes. The optical to X-ray flux variations are correlated and simultaneous except for two durations when they are anticorrelated. The flux variations, however, are anticorrelated with the X-ray spectral state while correlated with optical-UV (ultraviolet). Weekly binned Fermi-LAT data around the duration of the highest X-ray activity show a few detections with a log-parabola model but none with a power law, yet the extracted LAT spectral energy distribution of the high-activity duration for both the models is similar and shows a hardening above 1 GeV. Further, near-infrared data indicate strong spectral change, resembling a thermal component. Overall, the combined optical to gamma-ray broadband spectrum establishes the observed variations to a new high-energy-peaked broadband emission component, similar to the one seen during the highest reported X-ray flux state of the source in 2017. The observed activities indicate some peculiar features that seem to be characteristic of this emission component, while its appearance a few years around the claimed similar to 12 yr optical outbursts strongly indicates a connection between the two. (AU)

• Processo FAPESP: 13/10559-5 - Investigação de fenômenos de altas energias e plasmas astrofísicos: teoria, simulações numéricas, observações e desenvolvimento de instrumentação para o Cherenkov Telescope Array (CTA)
• Beneficiário: Elisabete Maria de Gouveia Dal Pino
• Modalidade de apoio: Auxílio à Pesquisa - Projetos Especiais