Swift XRT/UVOT follow-up of the renewed flaring activity of blazar PKS 0514-459

ATel #14645; Rukaiya Khatoon (Tezpur Univ), Raj Prince (CFT), and Rupjyoti Gogoi (Tezpur Univ)
on 19 May 2021; 15:41 UT
Credential Certification: Aditi Agarwal (aditiagarwal.phy@gmail.com)

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The current flaring activity of the blazar, PKS 0514-459 (R.A = 78.938767 deg, Dec. = -45.945369 deg (J2000), Costa & Loyola 1996, A&AS, 115, 75) located at z=0.194 (Stickel, Kuehr, & Fried 1993, A&AS, 97, 483), has been reported in gamma-ray and optical bands detected by Fermi-LAT, AGILE, and MASTER teams (ATel #14633, ATel #14634, ATel #14644). We conducted a follow-up observation of this flaring activity using Swift-XRT and UVOT observatory on 2021 May 18 for an exposure of ~ 2 ks.

We report the preliminary analysis results using the Swift-XRT and UVOT observations. The extracted Swift-XRT spectrum in the 0.3-10 keV range can be fitted by an absorbed power-law model, with the absorption is fixed at the Galactic value of N_H = 2.16 x 10^20 cm^-2 (Kalberla et al. 2005, A&A, 440, 775). The resulting unabsorbed flux is ~ 1.3 (+0.28, -0.26) x 10^-11 erg cm^-2 s^-1 with a photon index of 1.71+/-0.3. The flux obtained from our analysis matches well with the flux 1.3+/-0.1 x 10^-11 erg cm^-2 s^-1 obtained using the previous observations of 2020 December 4 (ATel #14245), which was reported as the highest flux of PKS 0514-459 ever detected by the XRT. However, the photon index estimated from our analysis is softer than the index 1.3 reported using the observation of 2020 December 4. We will follow up the activity of the source using the upcoming Swift observations.

We perform the UVOT analysis with six filters, viz. V, B, U, UVW1, UVM2 and UVW2 with time exposure as 39.09s, 39.15s, 39.16s, 79.49s, 130.34s, and 159.22s respectively. The magnitudes obtained in the AB system is 14.41 +/- 0.05 mag (statistical error only) for the V band, 14.76 +/- 0.04 mag for B band, 15.25 +/- 0.04 mag for U band, 15.82 +/- 0.04 mag for UVW1 band, 15.98 +/- 0.04 mag for UVM2 band and 16.17 +/- 0.03 mag for UVW2 band.

We encourage further multi-wavelength observations of this object. We would like to thank the Swift Team for the extremely rapid and efficient scheduling of the ToO observation.