Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst
We present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by <i>Swift</i> satellite during September 2019–March 2020. In this period, the source showed moderate variability characterized by variabi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-08-01
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| Series: | Galaxies |
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| Online Access: | https://www.mdpi.com/2075-4434/8/3/58 |
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| author | Nibedita Kalita Alok C. Gupta Minfeng Gu |
| author_facet | Nibedita Kalita Alok C. Gupta Minfeng Gu |
| author_sort | Nibedita Kalita |
| collection | DOAJ |
| description | We present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by <i>Swift</i> satellite during September 2019–March 2020. In this period, the source showed moderate variability characterized by variability amplitude of ∼22–31% in all the wavelengths on a short timescale, except the hard X-ray band which was variable by only ∼8%. We observed that the X-ray flux of the source was significantly dominated by the soft photons below 2 keV. Soft lags of ∼45 days were detected between the optical/UV and soft X-ray emissions, while there is no correlation between the hard X-rays and the lower energy bands indicating the presence of two emission components or electron populations. Although two components contribute to the X-ray emission, most of the 0.3–10 keV spectra were well fitted with an absorbed power-law model which outlines the dominance of synchrotron over inverse Compton (IC) mechanism. The X-ray spectra follow a weak “softer when brighter” trend. |
| first_indexed | 2024-03-10T17:52:19Z |
| format | Article |
| id | doaj.art-e87edc18ff0c49d796e6ca7e7c2ae488 |
| institution | Directory Open Access Journal |
| issn | 2075-4434 |
| language | English |
| last_indexed | 2024-03-10T17:52:19Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Galaxies |
| spelling | doaj.art-e87edc18ff0c49d796e6ca7e7c2ae4882023-11-20T09:19:36ZengMDPI AGGalaxies2075-44342020-08-01835810.3390/galaxies8030058Temporal and Spectral Variability of OJ 287 before the April–June 2020 OutburstNibedita Kalita0Alok C. Gupta1Minfeng Gu2Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, ChinaAryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263001, IndiaKey Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, ChinaWe present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by <i>Swift</i> satellite during September 2019–March 2020. In this period, the source showed moderate variability characterized by variability amplitude of ∼22–31% in all the wavelengths on a short timescale, except the hard X-ray band which was variable by only ∼8%. We observed that the X-ray flux of the source was significantly dominated by the soft photons below 2 keV. Soft lags of ∼45 days were detected between the optical/UV and soft X-ray emissions, while there is no correlation between the hard X-rays and the lower energy bands indicating the presence of two emission components or electron populations. Although two components contribute to the X-ray emission, most of the 0.3–10 keV spectra were well fitted with an absorbed power-law model which outlines the dominance of synchrotron over inverse Compton (IC) mechanism. The X-ray spectra follow a weak “softer when brighter” trend.https://www.mdpi.com/2075-4434/8/3/58BL Lac objectsindividualOJ 287 galaxiesactive-galaxiesjets-radiation mechanismsnon-thermal X-rays |
| spellingShingle | Nibedita Kalita Alok C. Gupta Minfeng Gu Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst Galaxies BL Lac objects individual OJ 287 galaxies active-galaxies jets-radiation mechanisms non-thermal X-rays |
| title | Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst |
| title_full | Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst |
| title_fullStr | Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst |
| title_full_unstemmed | Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst |
| title_short | Temporal and Spectral Variability of OJ 287 before the April–June 2020 Outburst |
| title_sort | temporal and spectral variability of oj 287 before the april june 2020 outburst |
| topic | BL Lac objects individual OJ 287 galaxies active-galaxies jets-radiation mechanisms non-thermal X-rays |
| url | https://www.mdpi.com/2075-4434/8/3/58 |
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