Swift follow-up of the flaring high-z FSRQ PKS 0537-286
ATel #15415; Filippo D'Ammando (INAF-IRA Bologna)
on 6 Jun 2022; 13:43 UT
Credential Certification: Filippo D'Ammando (dammando@ira.inaf.it)
Subjects: X-ray, AGN, Black Hole, Blazar, Quasar
Following the gamma-ray flaring activity of the high redshift (z = 3.104, Osmer et al. 1994, ApJ, 436, 678) flat spectrum radio quasar PKS 0537-286 detected by Fermi-LAT on 2022 May 28 (ATel #15405), Swift observations were performed on June 2, 3, and 4.
Swift-XRT data were taken in Photon Counting mode for a net exposure of about 1.5, 1.8, and 1.2 ksec, respectively. The X-ray spectrum (0.3-10 keV) observed on 2022 June 2, 3, and 4 can be fit by an absorbed power law model with a HI column density consistent with the Galactic value in the direction of the source (n_H = 1.8 x 10^20 cm^-2, Ben Bekhti N. et al., 2016, A&A, 594, A116) and a photon index of 1.17 +/- 0.18, 1.17 +/- 0.16, and 1.35 +/- 0.23, respectively. The corresponding (observed) 0.3-10 keV fluxes are (7.0 +/- 0.7) x10^-12 erg cm^-2 s^-1, (7.4 +/- 0.8) x10^-12 erg cm^-2 s^-1, and (5.2 +/- 0.7) x10^-12 erg cm^-2 s^-1, indicating a high flux level on 2022 June 2 and 3 with respect to the fluxes observed by XRT during 2005-2021 (i.e. 2.3-9.8 x10^-12 erg cm^-2 s^-1), although not comparable to the peak value observed on 2020 December 30.
In consideration of the ongoing activity of this source, confirmed also by the Swift-XRT observations, we encourage further multi-wavelength observations.
We would like to thank the Swift Team for making these observations possible, in particular K. L. Page as the Swift Observatory Duty Scientist.
