2010A&A...512A...9B


Query : 2010A&A...512A...9B

2010A&A...512A...9B - Astronomy and Astrophysics, volume 512, A9-9 (2010/3-1)

On the nature of the Cygnus X-2 like Z-track sources.

BALUCINSKA-CHURCH M., GIBIEC A., JACKSON N.K. and CHURCH M.J.

Abstract (from CDS):

Based on the results of applying the extended ADC emission model for low mass X-ray binaries to three Z-track sources: GX340+0, GX5-1 and CygX-2, we propose an explanation of the CygnusX-2 like Z-track sources. The Normal Branch is dominated by the increasing radiation pressure of the neutron star caused by a mass accretion rate that increases between the soft apex and the hard apex. The radiation pressure continues to increase on the Horizontal Branch becoming several times super-Eddington. We suggest that this disrupts the inner accretion disk and that part of the accretion flow is diverted vertically forming jets which are detected by their radio emission on this part of the Z-track. We thus propose that high radiation pressure is the necessary condition for the launching of jets. On the Flaring Branch there is a large increase in the neutron star blackbody luminosity at constant mass accretion rate indicating an additional energy source on the neutron star. We find that there is good agreement between the mass accretion rate per unit emitting area of the neutron star {dot}(m) at the onset of flaring and the theoretical critical value at which burning becomes unstable. We thus propose that flaring in the CygnusX-2 like sources consists of unstable nuclear burning. Correlation of measurements of kilohertz QPO frequencies in all three sources with spectral fitting results leads to the proposal that the upper kHz QPO is an oscillation always taking place at the inner accretion disk edge, the radius of which increases due to disruption of the disk by the high radiation pressure of the neutron star.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: neutron - X-rays: binaries - X-rays: individual: Cyg X-2 - X-rays: individual: GX340+0 - X-rays: individual: GX5-1

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 V* V818 Sco LXB 16 19 55.0692669024 -15 38 25.017666540 11.60 12.40 11.1     Oev 1594 0
2 4U 1624-49 LXB 16 28 05.5318788600 -49 12 40.011095160           ~ 216 0
3 4U 1642-45 LXB 16 45 47.7 -45 36 40     14.30     ~ 401 1
4 [KRL2007b] 214 LXB 17 00 58.46 -46 11 08.6           ~ 231 0
5 V* V1101 Sco LXB 17 05 44.4916006152 -36 25 23.049324480   20.10 18.6     ~ 425 0
6 4U 1758-25 LXB 18 01 09.7308060816 -25 04 44.120221284     11.08     ~ 634 1
7 V* NP Ser LXB 18 16 01.389 -14 02 10.62   18.8       K 624 2
8 V* V1341 Cyg LXB 21 44 41.1544345272 +38 19 17.066570988 15.00 15.13 14.68 15.00   A9III 1116 1

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2023.02.04-09:32:50

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