On the origin of quiescent X-ray emission from A0535+26

Authors
Citation
Nr. Ikhsanov, On the origin of quiescent X-ray emission from A0535+26, ASTRON ASTR, 367(2), 2001, pp. 549-556
Citations number
30
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
367
Issue
2
Year of publication
2001
Pages
549 - 556
Database
ISI
SICI code
0004-6361(200102)367:2<549:OTOOQX>2.0.ZU;2-C
Abstract
The quiescent X-ray emission from A0535+26 (L-x similar to 2 10(35) ergs(-1 )) is explored in terms of the spherically symmetrical accretion onto a mag netized neutron star. I find the magnetospheric boundary of the neutron sta r in A0535+26 to be stable with respect to interchange instabilities. The f astest mode by which the accreting plasma can enter the magnetosphere is th e magnetic lines reconnection. Under this condition the quiescent X-ray lum inosity of the system can be explained provided the mass capture rate by th e neutron star from the wind of the Be companion of similar to 10(-9) m(cir cle dot) yr(-1). I show this value to be in a good agreement with the mass capture rate independently evaluated from the established parameters of the Be star circumstellar environment. The suggested approach allows to interp ret the low luminous state of the system (L-x similar to 4 10(33) erg s(-1) ) in August - November 1998 in terms of the accretion powered pulsar model. I find the mass capture rate by the neutron star during this time of 3 10( -11) M-circle dot yr(-1). This can be realized provided the plasma density in the circumstellar disk of the Be companion is by two orders of magnitude smaller than its average value. Under this condition the disk is expected to be invisible in the optical/IR.