Hunting for the nature of the enigmatic narrow-line Seyfert 1 galaxy PKS 2004-447
Berton M, Peluso G, Marziani P, Komossa S, Foschini L, Ciroi S, Chen S, Congiu E, Gallo LC, Bjorklund I, Crepaldi L, Di Mille F, Jaervelae E, Kotilainen J, Kreikenbohm A, Morrell N, Romano P, Sani E, Terreran G, Tornikoski M, Vercellone S, Vietri A (2021)
Publication Type: Journal article
Publication year: 2021
Journal
Book Volume: 654
Article Number: A125
DOI: 10.1051/0004-6361/202141409
Abstract
Narrow-line Seyfert 1 (NLS1) galaxies are a class of active galactic nuclei (AGN) that, in some cases, can harbor powerful relativistic jets. One of them, PKS 2004-447, shows γ-ray emission, and underwent its first recorded multifrequency flare in 2019. However, past studies revealed that in radio this source can be classified as a compact steep-spectrum source (CSS), suggesting that, unlike other γ-ray sources, the relativistic jets of PKS 2004-447 have a large inclination with respect to the line of sight. We present here a set of spectroscopic observations of this object, aimed at carefully measuring its black hole mass and Eddington ratio, determining the properties of its emission lines, and characterizing its long term variability. We find that the black hole mass is (1.5 ± 0.2)×107 M⊙, and the Eddington ratio is 0.08. Both values are within the typical range of NLS1s. The spectra also suggest that the 2019 flare was caused mainly by the relativistic jet, while the accretion disk played a minor role during the event. In conclusion, we confirm that PKS 2004-447 is one of the rare examples of γ-ray emitting CSS/NLS1s hybrid, and that these two classes of objects are likely connected in the framework of AGN evolution.
Involved external institutions
Northwestern University
United States (USA) (US)
Saint Mary's University
Canada (CA)
University of Turku / Turun yliopisto
Finland (FI)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
Carnegie Observatories
United States (USA) (US)
University of Padua / Universita degli Studi di Padova
Italy (IT)
Max-Planck-Institut für Radioastronomie / Max Planck Institute for Radio Astronomy
Germany (DE)
European Southern Observatory (ESO)
Germany (DE)
European Space Astronomy Centre (ESAC)
Spain (ES)
Aalto University Espoo
Finland (FI)
Universidad de Santiago de Chile (USACH) / University of Santiago, Chile
Chile (CL)
United States (USA) (US)
Saint Mary's University
Canada (CA)
University of Turku / Turun yliopisto
Finland (FI)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
Carnegie Observatories
United States (USA) (US)
University of Padua / Universita degli Studi di Padova
Italy (IT)
Max-Planck-Institut für Radioastronomie / Max Planck Institute for Radio Astronomy
Germany (DE)
European Southern Observatory (ESO)
Germany (DE)
European Space Astronomy Centre (ESAC)
Spain (ES)
Aalto University Espoo
Finland (FI)
Universidad de Santiago de Chile (USACH) / University of Santiago, Chile
Chile (CL)
How to cite
APA:
Berton, M., Peluso, G., Marziani, P., Komossa, S., Foschini, L., Ciroi, S.,... Vietri, A. (2021). Hunting for the nature of the enigmatic narrow-line Seyfert 1 galaxy PKS 2004-447. Astronomy & Astrophysics, 654. https://doi.org/10.1051/0004-6361/202141409
MLA:
Berton, Marco, et al. "Hunting for the nature of the enigmatic narrow-line Seyfert 1 galaxy PKS 2004-447." Astronomy & Astrophysics 654 (2021).
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