The radio structure of the narrow-line Seyfert 1 Mrk 783 with VLBA and e-MERLIN. Issue 3 (1st October 2020)

• Record Type: Journal Article
• Authors: Congiu, E; Kharb, P; Tarchi, A; Berton, M; Caccianiga, A; Chen, S; Crepaldi, L; Di Mille, F; Järvelä, E; Jarvis, M E; La Mura, G; Vietri, A
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 499:Issue 3(2020)
• Page Start: 3149
• Page End: 3157
• Publication Date: 2020-10-01
• Subjects: galaxies: individual: Mrk 783 -- galaxies: Seyfert -- radio continuum: galaxies; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa3024
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: In this paper, we present the analysis of new radio and optical observations of the narrow-line Seyfert 1 galaxy Mrk 783. $1.6\, \mathrm{GHz}$ observations performed with the e-MERLIN interferometer confirm the presence of the diffuse emission previously observed. The Very Long Baseline Array (VLBA) also detects the nuclear source both at $1.6\, \mathrm{GHz}$ ( L band) and $5\, \mathrm{GHz}$ ( C band). While the L -band image shows only an unresolved core, the C -band image shows the presence of a partially resolved structure at a position angle of 60 ○ . The brightness temperature of the emission in both bands (${\gt}10^6\, \mathrm{K}$ ) suggests that it is a pc-scale jet produced by the active galactic nucleus. The relatively steep VLBA spectral index (αVLBA = 0.63 ± 0.03) is consistent with the presence of optically thin emission on milliarcsecond scales. Finally, we investigated two possible scenarios that can result in the misalignment between the kpc and pc-scale radio structure detected in the galaxy. We also analysed the optical morphology of the galaxy, which suggests that Mrk 783 underwent a merging in relatively recent times.