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Presentation . 2026
License: CC BY
Data sources: Datacite
ZENODO
Presentation . 2026
License: CC BY
Data sources: Datacite
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An X-ray and optical spectral study of the changing-look narrow-line Seyfert 1 2MASX J0413-0050

Authors: Vietri, Amelia;

An X-ray and optical spectral study of the changing-look narrow-line Seyfert 1 2MASX J0413-0050

Abstract

Changing-look (CL) active galactic nuclei (AGN) exhibit dramatic spectral and flux variations, caused by changes in the accretion rate (changing-state, CS-AGN) or in the line-of-sight column density (changing-obscuration, CO-AGN). Here I present J0413-0050, initially identified as a narrow-line Seyfert 1 (NLS1) galaxy, which was observed in 2004 and again in 2021, showing the complete disappearance of the Hß line. A third observation confirmed the absence of Hß and the broad Ha component, along with a significant decrease in the continuum level. Meanwhile, the X-ray flux increased across 3 observations spanning a decade, with a particularly notable spike (2 dex higher) in the most recent spectrum. A new optical spectrum then revealed the reappearance of both the narrow Hß and the broad components of Hß and Ha. J0413-0050 may have experienced several switch-on/switch-off phases, with an unknown timescale, potentially affecting the accretion power and thus the optical continuum and the emission lines coming from the broad-line region (BLR). In this talk, I explore all the possible scenarios that could explain these unpredictable variations including CS-AGN behaviour, disc wind or clumpy medium obscuring the BLR, or even BLR 'holidays'. New simultaneous optical/X-rays data I obtained may confirm one of these hypotheses. However, the case of J0413-0050 validates the idea that even highly accreting NLS1s can experience CL phenomena.

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
Average
Average
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