2021ApJ...921...18K -
Astrophys. J., 921, 18-18 (2021/November-1)
Blazar OJ 287 after first VHE activity: tracking the reemergence of the HBL-like component in 2020.
KUSHWAHA P., PAL M., KALITA N., KUMARI N., NAIK S., GUPTA A.C., DE GOUVEIA DAL PINO E.M. and GU M.
Abstract (from CDS):
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 ∼12 yr optical outbursts strongly indicates a connection between the two.
Abstract Copyright:
© 2021. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Blazars - Relativistic jets - High energy astrophysics - Active galaxies - Non-thermal radiation sources - BL Lacertae objects - Supermassive black holes - X-ray active galactic nuclei
Simbad objects:
3
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