The post-quiescence properties of Cir X-1 at orbital phase around periastron observed by NuSTAR and NICER

ABSTRACT Cir X-1 is an unusual X-ray binary, which has resumed periodic outbursts since August 2019. We investigate the post-quiescence spectral properties of Cir X-1 at orbital phase around the periastron using NICER and NuSTAR X-ray observatories after the resumption of outbursts. We identify two...

Full description

Saved in:
Bibliographic Details
Published inMonthly notices of the Royal Astronomical Society Vol. 527; no. 3; pp. 8029 - 8042
Main Authors Yu, Z L, Zhang, S, Chen, Y P, Kong, L D, Wang, P J, Shui, Q C, Peng, J Q, Yan, Z, Li, X D, Zhang, S N
Format Journal Article
LanguageEnglish
Published London Oxford University Press 01.01.2024
Subjects
Absorption
Binary stars
Observatories
Outbursts
Stellar winds
X ray binaries
X ray stars
X-rays: binaries
accretion, accretion discs
X-rays: individual: Cir X-1
Online AccessGet full text

Cover

More Information
Summary:ABSTRACT Cir X-1 is an unusual X-ray binary, which has resumed periodic outbursts since August 2019. We investigate the post-quiescence spectral properties of Cir X-1 at orbital phase around the periastron using NICER and NuSTAR X-ray observatories after the resumption of outbursts. We identify two distinct classes of spectral properties. The first class exhibits highly ionized absorption, whereas the second class does not. We suggest that the ionized absorption originates from the shelter of the disc wind, while the low-ionized/neutral absorption arises from the companion’s stellar wind. We also suggest that the disc wind may be always present in both classes, and a warped precession disc could alter the visibility of the disc wind.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stad3696