Multifrequency variability study of flat-spectrum radio quasar PKS 0346-27

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We have presented a multiwavelength temporal and spectral study of the blazar PKS 0346-27 for the period 2019 January–2021 December (MJD 58484–59575) using data from Fermi-LAT (γ-rays), Swift-XRT (X-rays), and Swift-UVOT (ultraviolet and optical). We identified multiple flaring episodes by analysing the gamma-ray light curve generated from the Fermi-LAT data over a 2-yr period. The light curves of these individual gamma-ray flares with 1-d binning were then modelled using a sum-of-exponentials fit. We found the minimum variability times for the gamma-ray light curve to be 1.34 ± 0.3 d and a range of 0.1–3.2 d for the Swift wavelengths, suggesting the compactness of the source. The broad-band emission mechanism was studied by modelling the simultaneous multiwaveband spectral energy distributions (SEDs) using the one-zone leptonic emission mechanism. We found that the optical-UV and X-ray data can be explained by the synchrotron and synchrotron self-Compton (SSC) emissions. However, the disc component of the external Compton (EC) radiation is dominant at higher energies with contributions from the EC broad-line region component and SSC. Further, we performed a power spectral density analysis with data from the gamma-ray light curve using the power spectrum response method. With the power-law model, the best-fitting slope of 2.15 ± 0.87 was found. This source could be a promising target for the upcoming Cherenkov telescope array for its harder spectrum at lower energies (tens of GeV).