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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Author(s):
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]
Total Authors: 8
Affiliation:
[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
Total Affiliations: 6
Document type: Journal article
Source: ASTROPHYSICAL JOURNAL; v. 921, n. 1 NOV 2021.
Web of Science Citations: 0
Abstract

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)

FAPESP's process: 13/10559-5 - Investigation of high energy and plasma astrophysics phenomena: theory, numerical simulations, observations, and instrument development for the Cherenkov Telescope Array (CTA)
Grantee:Elisabete Maria de Gouveia Dal Pino
Support Opportunities: Special Projects