Is there a highly magnetized neutron star in GX 301-2?

被引:53
作者
Doroshenko, V. [1 ]
Santangelo, A. [1 ]
Suleimanov, V. [1 ,5 ]
Kreykenbohm, I. [2 ,3 ]
Staubert, R. [1 ]
Ferrigno, C. [1 ,4 ]
Klochkov, D. [1 ]
机构
[1] Inst Astron & Astrophys, D-72076 Tubingen, Germany
[2] Dr Karl Remeis Sternwarte, D-96049 Bamberg, Germany
[3] ECAP, D-91058 Erlangen, Germany
[4] ISDC Data Ctr Astrophys, CH-1290 Versoix, Switzerland
[5] Kazan VI Lenin State Univ, Kazan 420008, Russia
关键词
pulsars: individual: GX 301-2; stars: neutron; binaries: general; X-RAY PULSARS; WIND-ACCRETION; ORBITAL CYCLE; STELLAR WIND; WRAY-977; SPECTROSCOPY; SIMULATIONS; HYPERGIANT; MECHANISM; SPECTRUM;
D O I
10.1051/0004-6361/200912951
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present the results of an in-depth study of the long-period X-ray pulsar GX 301-2. Using archival data of INTEGRAL, RXTE ASM, and CGRO BATSE, we study the spectral and timing properties of the source. Comparison of our timing results with previously published work reveals a secular decay of the orbital period at a rate of similar or equal to-3.25 x 10(-5) dyr(-1), which is an order of magnitude faster than for other known systems. We argue that this is probably result either of the apsidal motion or of gravitational coupling of the matter lost by the optical companion with the neutron star, although current observations do not allow us to distinguish between those possibilities. We also propose a model to explain the observed long pulse period. We find that a very strong magnetic field B similar to 10(14) G can explain the observed pulse period in the framework of existing models for torques affecting the neutron star. We show that the apparent contradiction with the magnetic field strength B-CRSF similar to 4 x 10(12) G derived from the observed cyclotron line position may be resolved if the line formation region resides in a tall accretion column of height similar to 2.5-3 R-NS. The color temperature measured from the spectrum suggests that such a column may indeed be present, and our estimates show that its height is sufficient to explain the observed cyclotron line position.
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页数:10
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