Swift follow-up of the gamma-ray flare of high-redshift blazar S5 0212+73
ATel #16684; Rukaiya Khatoon (North-West University), Markus Boettcher (North-West University)
on 2 Jul 2024; 17:39 UT
Credential Certification: Rukaiya Khatoon (rukaiyakhatoon12@gmail.com )
Subjects: X-ray, AGN, Blazar, Quasar
The gamma-ray flare from the blazar, Flat Spectrum Radio Quasar (FSRQ) S5 0212+73 (R.A = 34.378388 deg, Dec. = +73.825728 deg, (J2000), Johnston et al. 1995, AJ, 110, 880), located at z=2.34623 (Koss et al. 2022, ApJS, 261, 2), was observed on June 25-27, 2024, using Fermi-LAT (ATel #16679). This marks the first report of enhanced gamma-ray activity from this source in the ~16 years of Fermi-LAT operation. We conducted follow-up observations of this flaring activity using the Swift observatory on June 29 and July 1, 2024 (observation ID: 00032098004,00032098005), with exposure times of ~1.3 kiloseconds for both observations.
We present the preliminary analysis results of the Swift-XRT data. The Swift-XRT spectrum (0.3-10 keV band) can be fitted with an absorbed power-law model, with the absorption fixed at the Galactic value of N_H = 2.66 x 10^21 cm^-2 (Kalberla et al. 2005, A&A, 440, 775). The resulting unabsorbed flux for the observation conducted on June 29, 2024 is ~1.10 (+0.27, -0.23) x 10^-11 erg cm^-2 s^-1 with a photon index of 0.69+/-0.30. Subsequent observations on July 1, 2024, indicated a slight decrease in flux to ~8.50 (+1.59, -1.48) x 10^-12 erg cm^-2 s^-1, with a photon index of 1.18+/-0.29. This suggests a trend of hardening with increased brightness in the X-ray band, contrasting with the ATel #16679 implication of a softening trend in the gamma-ray band. We will continue monitoring the source activity across multiple wavebands.
We encourage further multi-wavelength observations of this object. We would like to extend our gratitude to the Swift Team for their rapid and efficient scheduling of the ToO observation.
