19 citations · 42 across the 8 of their papers we have counts for
8 papers
An X-ray and optical spectral study of the changing-look narrow-line Seyfert 1 2MASX J0413-0050
A. Vietri, A. Tortosa, D. Ilić +12
Active galactic nuclei (AGN) showing dramatic spectral and flux variations, either due to changes in the accretion rate (changing-state, CS-AGN) of the supermassive black hole or i…
NOCTURNE. I. The radio spectrum of narrow-line Seyfert 1 galaxies
M. Berton, E. Järvelä, S. Chen +8
The origin of the radio emission in active galactic nuclei (AGN) is still debated. Multiple physical mechanisms can contribute to the spectrum at these frequencies, including relat…
A comprehensive radio study of narrow-line Seyfert 1 galaxies
I. Varglund, E. Järvelä, M. J. Hardcastle +2
Narrow-line Seyfert 1 (NLS1) galaxies are a type of active galactic nuclei (AGN) that were originally classified as sources with little to no radio emission. Although the class is…
The host galaxy of low-luminosity compact sources
A. Vietri, M. Berton, E. Järvelä +6
The term 'active galactic nuclei' (AGN) subtends a huge variety of objects, classified on their properties at different wavelengths. Peaked sources (PS) represent a class of AGN at…
Unprecedented extreme high-frequency radio variability in early-stage active galactic nuclei
E. Järvelä, T. Savolainen, M. Berton +9
We report on the discovery of one of the most extreme cases of high-frequency radio variability ever measured in active galactic nuclei (AGN), observed on timescales of days and ex…
A host galaxy study of southern narrow-line Seyfert 1 galaxies
I. Varglund, E. Järvelä, S. Ciroi +4
We studied seven nearby narrow-line Seyfert 1 (NLS1) galaxies in - and -bands with redshifts varying from 0.019 to 0.092. This is the first multi-source study targeting the…
Long-term Swift and Metsähovi monitoring of SDSS J164100.10+345452.7 reveals multi-wavelength correlated variability
P. Romano, A. Lähteenmäki, S. Vercellone +10
We report on the first multi-wavelength Swift monitoring campaign performed on SDSS J164100.10+345452.7, a nearby narrow-line Seyfert 1 galaxy formerly known as radio quiet which w…
Jetted narrow-line Seyfert 1 galaxies breaking the jet paradigm -- a comprehensive study of host galaxy morphologies
Irene Varglund, Emilia Järvelä, Anne Lähteenmäki +3
Narrow-line Seyfert 1 (NLS1) galaxies are unevolved active galactic nuclei (AGN) that exist predominantly in spiral galaxies. However, mostly due to the small number of sources stu…