A persistent ultraviolet outflow from an accreting neutron star binary transient

Castro Segura, N. and Knigge, C. and Pahari, M. and et al, . (2022) A persistent ultraviolet outflow from an accreting neutron star binary transient. Nature, 603 (7899). pp. 52-57. ISSN 0028-0836

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Abstract

All disc-accreting astrophysical objects produce powerful disc winds. In compact binaries containing neutron stars or black holes, accretion often takes place during violent outbursts. The main disc wind signatures during these eruptions are blue-shifted X-ray absorption lines, which are preferentially seen in disc-dominated ‘soft states’1,2. By contrast, optical wind-formed lines have recently been detected in ‘hard states’, when a hot corona dominates the luminosity3. The relationship between these signatures is unknown, and no erupting system has as yet revealed wind-formed lines between the X-ray and optical bands, despite the many strong resonance transitions in this ultraviolet (UV) region4. Here we report that the transient neutron star binary Swift J1858.6-0814 exhibits wind-formed, blue-shifted absorption lines associated with C iv, N v and He ii in time-resolved UV spectroscopy during a luminous hard state, which we interpret as a warm, moderately ionized outflow component in this state. Simultaneously observed optical lines also display transient blue-shifted absorption. Decomposing the UV data into constant and variable components, the blue-shifted absorption is associated with the former. This implies that the outflow is not associated with the luminous flares in the data. The joint presence of UV and optical wind features reveals a multi-phase and/or spatially stratified evaporative outflow from the outer disc5. This type of persistent mass loss across all accretion states has been predicted by radiation–hydrodynamic simulations6 and helps to explain the shorter-than-expected duration of outbursts7. © 2022, The Author(s), under exclusive licence to Springer Nature Limited.

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IITH Creators:

IITH Creators	ORCiD
Pahari, M.	UNSPECIFIED

Item Type:

Article

Additional Information:

N.C.S. and C.K. acknowledge support from the Science and Technology Facilities Council (STFC), and from STFC grant ST/M001326/1. Partial support for K.S.L.’s effort on the project was provided by NASA through grant numbers HST-GO-15984 and HST-GO-16066 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. N.C.S. thanks T. Royle for helping to coordinate the time-critical observations in this article. N.D.D. acknowledges support from a Vidi grant for the Netherlands Organization for Scientific Research (NWO). J.V.H.S. acknowledges support from STFC grant ST/R000824/1. M.A.P., J.C., F.J.-I. and T.M.D. acknowledge support from grants AYA2017-83216-P and PID2020-120323GB-I00. T.M.-D. also acknowledges RYC-2015-18148 and EUR2021-122010. T.M.-D. and M.A.P. acknowledge support from grants with references ProID2020010104 and ProID2021010132. J.M. acknowledges a Herchel Smith Fellowship at Cambridge. T.D.R. acknowledges a financial contribution from the agreement ASI-INAF n.2017-14-H.0. J.v.d.E. is supported by a Lee Hysan Junior Research Fellowship from St Hilda’s College, Oxford. G.V. acknowledges support by NASA grants 80NSSC20K1107, 80NSSC20K0803 and 80NSSC21K0213. M.Ö.A. acknowledges support from the Royal Society through the Newton International Fellowship program. J.A.C. acknowledges support from grants PICT-2017-2865 (ANPCyT), PID2019-105510GB-C32/AEI/10.13039/501100011033 and FQM-322, as well as FEDER funds.

Uncontrolled Keywords:

absorption; accretion; corona; outflow; resonance; X-ray spectroscopy

Subjects:

Physics
Physics > Astronomy Astrophysics

Divisions:

Department of Physics

Depositing User:

. LibTrainee 2021

Date Deposited:

22 Jul 2022 06:15

Last Modified:

22 Jul 2022 06:15