Swift XRT follow-up observations of the FSRQ 3C 345
ATel #16329; Nibedita Kalita (Polar Research Institute of China, Shanghai, China)
on 10 Nov 2023; 03:10 UT
Credential Certification: Nibedita Kalita (nibeditaklt1@gmail.com)
Subjects: X-ray, AGN, Blazar
Following the Fermi-LAT detection of renewed gamma-ray activity (ATel #16274) from the flat spectrum radio quasar 3C 345, we requested a Swift Target-of-Opportunity observations of the source (request number 19490).
The target was observed by the X-Ray telescope on board the Neil Gehrels Swift Observatory (Swift-XRT ) between October 10 to November 4, 2023, with a total exposure time of around 18ks. X-ray spectral analysis indicates that the source was in a high state on October 29, 2023, with an unabsorbed 0.3-10 keV X-ray flux of 3.67 x 10^-10 erg cm^-2 s^-1. This corresponds to a flux increase by ~ 2 order of magnitudes relative to the fluxes estimated from previous observations taken during October 10 to 19, 2023 and April 2022. The enhanced activity lasted for a short period of time as the flux level fell back to its normal state by November 4, 2023.
We fitted the 0.3-10 keV spectra with a simple power law model by fixing the HI column density at N_HI = 8.89 \times x 10^19 cm^-2 (Kalberla et al. 2005, A&A, 440, 775). The list of unabsorbed 0.3 -10 keV X-ray fluxes for different dates is given below.
Date --- Flux (error) in erg cm^-2 s^-1
10/10/2023 --- 4.60 (+/- 0.76) x 10^-12
11/10/2023 --- 6.22 (+/- 0.79) x 10^-12
12/10/2023 --- 3.15 (+/- 0.68) x 10^-12
13/10/2023 --- 4.15 (+/- 0.72) x 10^-12
14/10/2023 --- 4.00 (+/- 0.69) x 10^-12
15/10/2023 --- 5.29 (+/- 0.74) x 10^-12
16/10/2023 --- 4.33 (+/- 0.65) x 10^-12
19/10/2023 --- 4.25 (+/- 0.62) x 10^-12
29/10/2023 --- 3.67 (+/- 0.80) x 10^-10
04/11/2023 --- 5.01 (+/- 0.51) x 10^-12
We thank Neil Gehrels Swift Observatory for scheduling these observations.
