TY - JOUR

T1 - A multiwavelength study of the flat-spectrum radio quasar NVSS J141922−083830 covering four flaring episodes

AU - Buckley, D A H

AU - Britto, R J

AU - Chandra, S

AU - Krushinsky, V

AU - Böttcher, M

AU - Razzaque, S

AU - Lipunov, V

AU - Stalin, C S

AU - Gorbovskoy, E

AU - Tiurina, N

AU - Vlasenko, D

AU - Kniazev, A

N1 - Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d' Études Spatiales in France. The SALT spectra were obtained under the programmes 2014-2- DDT-002 (PI: AK) and 2016-2-LSP-001 (PI: DB). DB, RJB, MB, SR, and AK acknowledge support from the National Research Foundation, South Africa and the South African Gamma-ray Astronomy Programme (SA-GAMMA). The work of MB is supported through the South African Research Chair Initiative of the National Research Foundation 13 and the Department of Science and Innovation, South Africa, under SARChI Chair grant No. 64789. The work of VK was supported by the Ministry of Science and Higher Education of the Russian Federation, topic No. FEUZ-2020-0038.

PY - 2022/11/10

Y1 - 2022/11/10

N2 - We present multiwavelength observations and a model for flat-spectrum radio quasar (FSRQ) NVSS J141922-083830, originally classified as a blazar candidate of unknown type (BCU II object) in the Third Fermi-LAT AGN Catalog. Relatively bright flares (>3 magnitudes) were observed on 2015 February 21 (MJD 57074) and 2018 September 8 (MJD 58369) in the optical band with the MASTER Global Robotic Nettelescopes. Optical spectra obtained with the Southern African Large Telescopeon 2015 March 1 (MJD 57082), during outburst, and on 2017 May 30 (MJD 57903), during quiescence, showed emission lines at 5325 angstrom and at approximate to 3630 angstrom that we identified as the Mg II 2798 angstrom and C III] 1909 angstrom lines, respectively, and hence derived a redshift z = 0.903. Analysis of Fermi-Large Area Telescope (LAT) data was performed in the quiescent regime (5 yr of data) and during four prominent flaring states in 2014 February-April, 2014 October-November, 2015 February-March, and 2018 September. We present spectral and timing analysis with Fermi-LAT. We report a hardening of the gamma-ray spectrum during the last three flaring periods, with a power-law spectral index Gamma = 2.0-2.1. The maximum gamma-ray flux level was observed on 2014 October 24 (MJD 56954) at (7.57 +/- 1.83) x 10(-7) ph cm(-2) s(-1). The multiwavelength spectral energy distribution (SED) during the 2015 February-March flare supports the earlier evidence of this blazar to belong to the FSRQ class. The SED can be well represented with a single-zone leptonic model with parameters typical of FSRQs, but also a hadronic origin of the high-energy emission cannot be ruled out.

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

UR - https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=tsmetrics&SrcApp=tsm_test&DestApp=WOS_CPL&DestLinkType=FullRecord&KeyUT=000881809100035

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=85145252910

U2 - 10.1093/mnras/stac2181

DO - 10.1093/mnras/stac2181

M3 - Article

VL - 517

SP - 5791

EP - 5804

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -