| Autor: |
S. Adhikari, P. Peñil, J. R. Westernacher-Schneider, A. Domínguez, M. Ajello, S. Buson, A. Rico, J. Zrake |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
|
| Zdroj: |
The Astrophysical Journal, Vol 965, Iss 2, p 124 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
1538-4357 |
| DOI: |
10.3847/1538-4357/ad310a |
| Popis: |
PG 1553+113 is a well-known blazar exhibiting evidence of a ∼2.2 yr quasiperiodic oscillation (QPO) in the radio, optical, X-ray, and γ -ray bands. Since QPO mechanisms often predict multiple QPOs, we search for a second QPO in its historical optical light curve covering a century of observations. Despite challenging data quality issues, we find hints of a 21.8 ± 4.7 yr oscillation. On its own, this ∼22 yr period has a modest statistical significance of 1.6 σ when accounting for the look-elsewhere effect. However, the joint significance of both the 2.2 and 22 yr periods arising from colored noise alone is ∼3.6 σ . The next peak of the 22 yr oscillation is predicted to occur around July 2025. We find that such a ∼10:1 relation between two periods can arise in the gas dynamics of a plausible supermassive black hole binary model of PG 1553+113. While the 22 yr QPO is preliminary, an interpretation of PG 1553+113's two QPOs in this binary model suggests that the binary engine has a mass ratio ≳0.2, an eccentricity ≲0.1, and accretes from a disk with characteristic aspect ratio ∼0.03. The putative binary radiates nHz gravitational waves, but the amplitude is ∼10–100 times too low for detection by foreseeable pulsar timing arrays. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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