Swift follow-up of the flaring FSRQ PMN J0231-4746
ATel #13212; F. D'Ammando (INAF-IRA Bologna), G. Principe (INAF-IRA Bologna), and R. Angioni (SSDC/INFN) on behalf of the Fermi Large Area Telescope Collaboration
on 22 Oct 2019; 13:57 UT
Credential Certification: Filippo D'Ammando (dammando@ira.inaf.it)
Subjects: Optical, Ultra-Violet, X-ray, Gamma Ray, AGN, Black Hole, Blazar, Quasar
Referred to by ATel #: 13248
Following the flaring activity of the flat spectrum radio quasar PMN J0231-4746 at redshift z=0.765 (Healey S. E. et al. 2008, ApJS, 175, 97) observed in gamma rays by Fermi-LAT on October 19 (ATel #13209), a Swift target of opportunity observation was performed on October 21.
Swift-XRT data were taken in Photon Counting mode for a net exposure of about 2.0 ksec. The X-ray spectrum (0.3-10 keV) observed in 2019 October 21 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 = 1.5 x 10^20 cm^-2, Ben Bekhti N. et al., 2016, A&A, 594, A116) and a photon index of 1.55 +/- 0.26. The corresponding 2-10 keV flux is (1.4+/-0.2) x10^-12 erg cm^-2 s^-1. The flux observed on 2019 October 21 is a factor of 4 higher than the value observed by Swift-XRT on 2009 November 5, (3.0+/-0.7) x10^-13 erg cm^-2 s^-1, with a photon index of 1.73 +/- 0.36.
Simultaneous Swift-UVOT observations were performed on 2019 October 21. The measured magnitudes are V = 16.64 +/-0.18, B = 16.99 +/- 0.08, U = 16.14 +/- 0.08, W1 = 16.02 +/- 0.09, M2 = 15.83 +/- 0.07, W2 = 16.19 +/- 0.08. The source is significantly brighter in UV with respect to the values observed in 2009 November 5, M2 = 17.28 +/- 0.10 and W2 = 17.42 +/- 0.08. This confirms the high activity state of the source in UV and X-rays.
In consideration of the ongoing activity of this source, confirmed also by the Swift observations, we encourage further multiwavelength observations. For this source the Fermi LAT contact person is Giacomo Principe (giacomo.principe@inaf.it).
We would like to thank the Swift Team for making these observations possible, in particular B. Sbarufatti as the Swift Observatory Duty Scientist.