A multiwavelength study of the flat-spectrum radio quasar NVSS J141922−083830 covering four flaring episodes

We present multiwavelength observations and a model for flat spectrum radio quasar NVSS J141922-083830, originally classified as blazar candidate of unknown type (BCU II object) in the Third Fermi-LAT AGN Catalog (3LAC). Relatively bright flares (>3 magnitudes) were observed on 21 February 2015 (MJD 57074) 8 September 2018 58369) optical band with MASTER Global Robotic Net (MASTER-Net) telescopes. Optical spectra obtained Southern African Large Telescope (SALT) 1 March 57082), during outburst, 30 May 2017 57903), quiescence, showed emission lines at 5325\r{A} $\approx$3630\r{A} that we identified Mg 2798\r{A} C III] 1909\r{A} lines, respectively, hence derived redshift z = 0.903. Analysis data was performed quiescent regime (5 years data) four prominent flaring states February-April 2014, October-November February-March 2018. spectral timing analysis Fermi-LAT. report hardening gamma-ray last three periods, power-law index $\Gamma 2.0$-$2.1$. The maximum flux level 24 October 2014 56954) $(7.57 \pm 1.83) \times 10^{-7}$ ph~cm$^{-2}$s$^{-1}$. multi-wavelength energy distribution flare supports earlier evidence this to belong FSRQ class. SED can be well represented single-zone leptonic parameters typical FSRQs, but also hadronic origin high-energy not ruled out.