Are There Magnetars in High-Mass X-Ray Binaries? The Case of Supergiant Fast X-Ray Transients

By E. Bozzo, L. Stella, M. Falanga. 2008

173 citations recorded by the source corpus.

In this paper we survey the theory of wind accretion in high-mass X-ray binaries hosting a magnetic neutron star and a supergiant companion. We concentrate on the different types of interaction between the inflowing wind matter and the neutron star magnetosphere that are relevant when accretion of matter onto the neutron star surface is largely inhibited; these include inhibition through the centrifugal and magnetic barriers. Expanding on earlier work, we calculate the expected luminosity for each regime and derive the conditions under which transition from one regime to another can take place. We show that very large luminosity swings (~104 or more on timescales as short as hours) can result from transitions across different regimes. The activity displayed by supergiant fast X-ray transients, a recently discovered class of high-mass X-ray binaries in our galaxy, has often been interpreted in terms of direct accretion onto a neutron star immersed in an extremely clumpy stellar wind. We show here that the transitions across the magnetic and/or centrifugal barriers can explain the variability properties of these sources as a result of relatively modest variations in the stellar wind velocity and/or density. According to this interpretation we expect that supergiant fast X-ray transients which display very large luminosity swings and host a slowly spinning neutron star are characterized by magnetar-like fields, irrespective of whether the magnetic or the centrifugal barrier applies. Supergiant fast X-ray transients might thus provide a new opportunity to detect and study magnetars in binary systems.

Subfields: Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/f531747cc68edc4cea7f66e308bdde0b7fecf1b5

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In Astronomy and Astrophysics

1. Bing Zhang
2. Pawan Kumar
3. E. Berger
4. A. Pe’er
5. F. Ryde
6. L. Amati
7. N. Langer
8. B. Metzger

In Computational Mechanics

1. N. Langer
2. M. Colpi
3. A. Ferrara
4. S. Ettori
5. Pawan Kumar
6. Sung-Chul Yoon
7. Luciano Rezzolla
8. Umberto De Maio

Citations in the corpus

• Formation of Double Neutron Star Systems (2017, background): “However, it is also possible that a strong reduction of the long-term mass-accretion rate is produced by the effect of a strong magnetic field and/or a fast spin of the NS, which could lead to magnetic and/or centrifugal barriers, respectively (Bozzo et al. 2008, 2016).”
• The THESEUS space mission concept: science case, design and expected performances (2017, background): “, 2016), and the origin of the bright flares possibly due to wind accretion onto a magnetar (Bozzo et al., 2008).”
• High-mass X-ray binaries in the Milky Way (2013, background): “6-1703 was also observed twice with XMMNewton close to the apastron, but not detected Bozzo et al. (2008b, 2012b).”