Kavli Affiliate: Kejia Lee
| First 5 Authors: Dengke Zhou, Dengke Zhou, , ,
| Summary:
Possible periodic features in fast radio bursts (FRBs) may provide insights
into their astrophysical origins. Using extensive observations from the
Five-hundred-meter Aperture Spherical radio Telescope (FAST), we conduct a
search for periodicity across multiple timescales in the exceptionally active
repeater source FRB 20240114A. A detailed analysis of 11,553 bursts reveals
three candidate periodic signals (3.4-6$sigma$), with frequencies of
approximately 1.486 Hz, 1.576 Hz, and 1.865 Hz. This finding offers tentative
evidence for a potential association with magnetar spin, although further
studies are necessary for definitive confirmation. On longer timescales, a
67.5-69.2 day activity cycle is identified using two independent methods, with
a significance exceeding $3.5sigma$. In the burst time series, quasi-periodic
oscillations (QPOs) in the range of a few hundred Hz are identified, with a
significance exceeding 5$sigma$, and a strong correlation is found between
their central frequencies and widths (Pearson $R=0.97$). The decomposed
temporal profiles of these QPOs suggest an amplitude-modulated quasi-periodic
signal. The burst clusters manifest periodic burst trains ranging from a few
milliseconds to several tens of milliseconds, revealing transient periodic
characteristics. Despite the unprecedentedly large sample size from a single
repeating FRB source during a time-continuous active period, no stable periodic
signals are detected. Instead, there are multiple QPOs that dynamically evolve
over time. These results clarify the bias of previous studies that occasionally
detected QPOs believed to be potentially related to the spin of compact
objects.
| Search Query: ArXiv Query: search_query=au:”Kejia Lee”&id_list=&start=0&max_results=3