The first broad-band X-ray view of the narrow-line Seyfert 1 Ton S180

Journal
Date Issued
2020
Author(s)
Matzeu, G. A.
•
•
Parker, M. L.
•
Reeves, J. N.
•
•
Porquet, D.
•
Middei, R.
•
Kammoun, E.
•
Lusso, E.
•
Alston, W. N.
•
Giustini, M.
•
Lobban, A. P.
•
Joyce, A. M.
•
Igo, Z.
•
Ebrero, J.
•
Ballo, L.
•
Santos-Lleó, M.
•
Schartel, N.
DOI
Abstract
We present joint XMM-Newton and NuSTAR observations of the 'bare' narrow-line Seyfert 1 Ton S180 (z = 0.062), carried out in 2016 and providing the first hard X-ray view of this luminous galaxy. We find that the 0.4-30 keV band cannot be self-consistently reproduced by relativistic reflection models, which fail to account simultaneously for the soft and hard X-ray emission. The smooth soft excess prefers extreme blurring parameters, confirmed by the nearly featureless nature of the Reflection Grating Spectrometer (RGS) spectrum, while the moderately broad Fe K line and the modest hard excess above 10 keV appear to arise in a milder gravity regime. By allowing a different origin of the soft excess, the broad-band X-ray spectrum and overall spectral energy distribution (SED) are well explained by a combination of (a) direct thermal emission from the accretion disc, dominating from the optical to the far/extreme UV; (b) Comptonization of seed disc photons by a warm (kTe ~ 0.3 keV) and optically thick (τ ~ 10) corona, mostly contributing to the soft X-rays; (c) Comptonization by a standard hot ($kT_{\rm \mathrm{ e}}\gtrsim 100$ keV) and optically thin (τ < 0.5) corona, responsible for the primary X-ray continuum; and (d) reflection from the mid/outer part of the disc. The two coronae are suggested to be rather compact, with $R_{\rm hot}\lesssim R_{\rm warm}\lesssim 10\, r_{\rm g}$. Our SED analysis implies that Ton S180 accretes at super-Eddington rates. This is a key condition for the launch of a wind, marginal (i.e. 3.1σ significance) evidence of which is indeed found in the RGS spectrum.
Volume
497
Issue
2
Start page
2352
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2020MNRAS.497.2352M
Rights
open.access
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