TY - JOUR
T1 - Chandra reveals a possible ultrafast outflow in the super-Eddington Be/X-ray binary Swift J0243.6+6124
AU - Van Den Eijnden, J.
AU - Degenaar, N.
AU - Schulz, N. S.
AU - Nowak, M. A.
AU - Wijnands, R.
AU - Russell, T. D.
AU - Herńandez Santisteban, J. V.
AU - Bahramian, A.
AU - MacCarone, T. J.
AU - Kennea, J. A.
AU - Heinke, C. O.
N1 - Funding Information:
We are grateful to the anonymous referee for their constructive comments that improved this paper, and to Belinda Wilkes and the Chandra scheduling team for rapidly accepting and performing the Director’s Discretionary Time observation. We thank Ciro Pinto, Mark Reynolds, and Jacco Vink for useful discussions on X-ray spectroscopy, super-Eddington accretion, and outflows. JvdE, ND, and JVHS are supported by a Vidi grant from the Netherlands Organization for Scientific Research (NWO) awarded to ND. TDR is supported by a Veni grant from the NWO. COH acknowledges
Funding Information:
an NSERC Discovery Grant. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. This research has made use of MAXI data provided by RIKEN, JAXA and the MAXI team. ASAS-SN is supported by National Science Foundation (NSF) grant AST-1515927. Development of ASAS-SN has been supported by NSF grant AST-0908816, the Center for Cosmology and AstroParticle Physics at the Ohio State University, the Mt. Cuba Astronomical Foundation, and by George Skestos.
Publisher Copyright:
© The Author(s) 2019.
PY - 2019/8/11
Y1 - 2019/8/11
N2 - Accretion at super-Eddington rates is expected to be accompanied by strong outflows. Such outflows are observed inGalactic X-ray binaries and extragalactic ultraluminous X-ray sources (ULXs). However, due to their large source distances, ULX outflows are challenging to detect and study in detail. Galactic neutron stars accreting from a Be-star companion at super- Eddington rates show many similarities to ULX pulsars, and therefore offer an alternative approach to study outflows in this accretion regime. Here, we present Chandra high-resolution spectroscopy of such a super-Eddington accreting neutron star, Swift J0243.6+6124, to search for wind outflow signatures during the peak of its 2017/2018 giant outburst.We detect narrow emission features at rest from Ne, Mg, S, Si, and Fe. In addition, we detect a collection of absorption features which can be identified in two ways: Either as all Fe transitions at rest (with a possible contribution from Mg), or a combination of three blue-shifted Ne and Mg lines at ∼0.22c, while the remaining lines are at rest. The second scenario would imply an outflow with a velocity similar to those seen in ULXs, including the ULX pulsar NGC 300 ULX-1. This result would also imply that Swift J0243.6+6124 launches both a jet, detected in radio and reported previously, and an ultrafast wind outflow simultaneously at super-Eddington accretion rates.
AB - Accretion at super-Eddington rates is expected to be accompanied by strong outflows. Such outflows are observed inGalactic X-ray binaries and extragalactic ultraluminous X-ray sources (ULXs). However, due to their large source distances, ULX outflows are challenging to detect and study in detail. Galactic neutron stars accreting from a Be-star companion at super- Eddington rates show many similarities to ULX pulsars, and therefore offer an alternative approach to study outflows in this accretion regime. Here, we present Chandra high-resolution spectroscopy of such a super-Eddington accreting neutron star, Swift J0243.6+6124, to search for wind outflow signatures during the peak of its 2017/2018 giant outburst.We detect narrow emission features at rest from Ne, Mg, S, Si, and Fe. In addition, we detect a collection of absorption features which can be identified in two ways: Either as all Fe transitions at rest (with a possible contribution from Mg), or a combination of three blue-shifted Ne and Mg lines at ∼0.22c, while the remaining lines are at rest. The second scenario would imply an outflow with a velocity similar to those seen in ULXs, including the ULX pulsar NGC 300 ULX-1. This result would also imply that Swift J0243.6+6124 launches both a jet, detected in radio and reported previously, and an ultrafast wind outflow simultaneously at super-Eddington accretion rates.
KW - Accretion, accretion discs
KW - Pulsars: Individual: Swift J0243.6+6124
KW - Stars: neutron
KW - X-rays: Binaries
UR - http://www.scopus.com/inward/record.url?scp=85072276188&partnerID=8YFLogxK
U2 - 10.1093/mnras/stz1548
DO - 10.1093/mnras/stz1548
M3 - Article
AN - SCOPUS:85072276188
VL - 487
SP - 4355
EP - 4371
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -