Modeling the time-variable broadband emission and correlation study of FSRQ S5 1044+71

Abstract

We present a detailed temporal and spectral analysis of the blazar S5 1044+71 using multiwavelength data obtained from the Fermi-LAT and Swift-XRT/UVOT telescopes. Applying the Bayesian block algorithm to the 3-day binned γ-ray light curve, we identify pronounced variability, including four major outbursts marked by significant flux enhancements. The highest flux recorded was (1.1 ± 0.2) × 10−6 photons cm−2 s −1 on 57868.5 MJD. Each outburst comprises multiple components, and light-curve profile analysis indicates predominantly symmetric temporal structures. The shortest variability timescale of 4.5 hr constrains the emission region to be located within 0.03 pc of the central engine, likely near the broad-line region (BLR). Additionally, two highest-energy photons were detected with energies of 46.4 GeV (on 57739.6 MJD) and 42.5 GeV (on 59161.9 MJD), observed outside the peak flaring activity. The fractional variability shows an overall increasing trend from UV/ optical to γ-ray bands, with a noticeable dip in the X-ray range, consistent with the shape of the broadband spectral energy distribution (SED). The flux distributions during flares exhibit lognormal or double-lognormal behavior, suggesting multiplicative variability processes and evolving emission zones. Cross-correlation analysis reveals a strong positive correlation between the γ-ray and X-ray bands, with X-rays lagging by 42.5 days. Broadband SED modeling across different flux states supports a one-zone leptonic scenario, with γ-ray emission produced via external Compton scattering of IR and BLR photons. High flux states show harder electron spectra, elevated break energies, and reduced magnetic fields—features consistent with efficient particle acceleration and Compton dominance.