2010A&A...519A..37F


Query : 2010A&A...519A..37F

2010A&A...519A..37F - Astronomy and Astrophysics, volume 519, A37-37 (2010/9-1)

X-ray variation statistics and wind clumping in Vela X-1.

FUERST F., KREYKENBOHM I., POTTSCHMIDT K., WILMS J., HANKE M., ROTHSCHILD R.E., KRETSCHMAR P., SCHULZ N.S., HUENEMOERDER D.P., KLOCHKOV D. and STAUBERT R.

Abstract (from CDS):

We investigate the structure of the wind in the neutron star X-ray binary system Vela X-1 by analyzing its flaring behavior. Vela X-1 shows constant flaring, with some flares reaching fluxes of more than 3.0Crab between 20-60keV for several 100s, while the average flux is around 250mCrab. We analyzed all archival INTEGRAL data, calculating the brightness distribution in the 20-60keV band, which, as we show, closely follows a log-normal distribution. Orbital resolved analysis shows that the structure is strongly variable, explainable by shocks and a fluctuating accretion wake. Analysis of RXTE ASM data suggests a strong orbital change of NH. Accreted clump masses derived from the INTEGRAL data are on the order of 5x1019-1021g. We show that the lightcurve can be described with a model of multiplicative random numbers. In the course of the simulation we calculate the power spectral density of the system in the 20-100keV energy band and show that it follows a red-noise power law. We suggest that a mixture of a clumpy wind, shocks, and turbulence can explain the measured mass distribution. As the recently discovered class of supergiant fast X-ray transients (SFXT) seems to show the same parameters for the wind, the link between persistent HMXB like Vela X-1 and SFXT is further strengthened.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - X-rays: binaries - X-rays: individual: Vela X-1 - methods: statistical

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 V* BQ Cam HXB 03 34 59.9116110096 +53 10 23.296879776   17.16 15.42 14.26 13.04 O8.5Ve 431 1
2 HD 74194 HXB 08 40 47.7915253032 -45 03 30.235569624 7.05 7.77 7.55 8.70   O8.5Ib-II(f)p 189 0
3 V* GP Vel HXB 09 02 06.8608812864 -40 33 16.899168060 6.85 7.37 6.87 6.31 6.05 B0.5Ia 1430 0
4 4U 1908+075 HXB 19 10 48.2133201408 +07 35 51.707133960           O7.5-9.5sg 110 0
5 HD 226868 HXB 19 58 21.6757355952 +35 12 05.784512688 9.38 9.72 8.91 8.42   O9.7Iabpvar 4122 0

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2022.08.10-04:33:23

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