Continued Swift observations of the FSRQ PKS 1127-14 during a high activity period
ATel #15397; Filippo D'Ammando (INAF-IRA Bologna)
on 24 May 2022; 11:28 UT
Credential Certification: Filippo D'Ammando (dammando@ira.inaf.it)
Subjects: Optical, Ultra-Violet, X-ray
Following the first Swift observations of the flat spectrum radio quasar PKS 1127-14 (z = 1.184; Wilkes 1986, MNRAS, 218, 331) after the gamma-ray flare detected by Fermi-LAT, performed on 2022 May 17 and 18 (ATel #15385), further Swift observations were obtained on May 20 and 23.
Swift-XRT data were taken in Photon Counting mode for a net exposure of about 2.1 ksec and 2.0 ksec, respectively. The X-ray spectrum (0.3-10 keV) observed on 2022 May 20 and 23 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 = 3.5 x 10^20 cm^-2, Ben Bekhti N. et al., 2016, A&A, 594, A116) and a photon index of 0.92 +/- 0.12 and 1.01 +/- 0.13, respectively. The corresponding (observed) 0.3-10 keV fluxes are (1.62 +/- 0.13) x10^-11 erg cm^-2 s^-1 and (1.39 +/- 0.11) x10^-11 erg cm^-2 s^-1, respectively, indicating a flux level comparable to the peak value observed on 2022 May 17.
Simultaneous Swift-UVOT observations were performed on 2022 May 20 and 23. The measured magnitudes in optical and UV bands show a brightness level similar to what is observed on 2022 May 17 (see ATel #15385).
The measured magnitudes are:
| Band | 2022 May 20 | 2022 May-23 |
|---|
| V | 16.72 +/- 0.08 | 16.74 +/- 0.08 |
| B | 16.93 +/- 0.06 | 16.91 +/- 0.06 |
| U | 15.93 +/- 0.06 | 15.83 +/- 0.06 |
| W1 | 15.73 +/- 0.07 | 15.79 +/- 0.07 |
| M2 | 15.92 +/- 0.07 | 15.87 +/- 0.07 |
| W2 | 16.17 +/- 0.07 | 16.05 +/- 0.06 |
In consideration of the ongoing activity of this source, confirmed also by the Swift observations, we encourage further multi-wavelength observations.
We would like to thank the Swift Team for making these observations possible, in particular M. H. Siegel as the Swift Observatory Duty Scientist.
