XMM-Newton campaign on the ultraluminous X-ray source NGC 247 ULX-1: outflows

Pinto, C.; Soria, R.; Walton, D.; D'Ai, A.; Pintore, F.; Kosec, P.; Alston, W.N.; Fuerst, F.; Middleton, M.J.; Roberts, T.P.; Del Santo, M.; Barret, D.; Ambrosi, E.; Robba, A.; Earnshaw, H.; Fabian, A.

doi:10.1093/mnras/stab1648

XMM-Newton campaign on the ultraluminous X-ray source NGC 247 ULX-1: outflows

Pinto, C.; Soria, R.; Walton, D.; D'Ai, A.; Pintore, F.; Kosec, P.; Alston, W.N.; Fuerst, F.; Middleton, M.J.; Roberts, T.P.; Del Santo, M.; Barret, D.; Ambrosi, E.; Robba, A.; Earnshaw, H.; Fabian, A.

Authors

C. Pinto

R. Soria

D. Walton

A. D'Ai

F. Pintore

P. Kosec

W.N. Alston

F. Fuerst

M.J. Middleton

Professor Tim Roberts t.p.roberts@durham.ac.uk
Professor

M. Del Santo

D. Barret

E. Ambrosi

A. Robba

H. Earnshaw

A. Fabian

Abstract

Most ultraluminous X-ray sources (ULXs) are believed to be powered by super-Eddington accreting neutron stars and, perhaps, black holes. Above the Eddington rate the disc is expected to thicken and to launch powerful winds through radiation pressure. Winds have been recently discovered in several ULXs. However, it is yet unclear whether the thickening of the disc or the wind variability causes the switch between the classical soft and supersoft states observed in some ULXs. In order to understand such phenomenology and the overall super-Eddington mechanism, we undertook a large (800 ks) observing campaign with XMM-Newton to study NGC 247 ULX-1, which shifts between a supersoft and classical soft ULX state. The new observations show unambiguous evidence of a wind in the form of emission and absorption lines from highly ionized ionic species, with the latter indicating a mildly relativistic outflow (−0.17c) in line with the detections in other ULXs. Strong dipping activity is observed in the light curve and primarily during the brightest observations, which is typical among soft ULXs, and indicates a close relationship between the accretion rate and the appearance of the dips. The latter is likely due to a thickening of the disc scale height and the wind as shown by a progressively increasing blueshift in the spectral lines.

Citation

Pinto, C., Soria, R., Walton, D., D'Ai, A., Pintore, F., Kosec, P., …Fabian, A. (2021). XMM-Newton campaign on the ultraluminous X-ray source NGC 247 ULX-1: outflows. Monthly Notices of the Royal Astronomical Society, 505(4), 5058-5074. https://doi.org/10.1093/mnras/stab1648

Journal Article Type	Article
Acceptance Date	Jun 3, 2021
Online Publication Date	Jun 10, 2021
Publication Date	2021-08
Deposit Date	Jul 2, 2021
Publicly Available Date	Nov 16, 2021
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	505
Issue	4
Pages	5058-5074
DOI	https://doi.org/10.1093/mnras/stab1648
Related Public URLs	https://arxiv.org/pdf/2104.11164.pdf

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This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.