2006A&A...452..975A


C.D.S. - SIMBAD4 rel 1.7 - 2021.04.16CEST11:02:32

2006A&A...452..975A - Astronomy and Astrophysics, volume 452, 975-984 (2006/6-4)

Probing the temporal variability of Cygnus X-1 into the soft state.

AXELSSON M., BORGONOVO L. and LARSSON S.

Abstract (from CDS):

Building on results from previous studies of Cygnus X-1, we analyze Rossi X-ray Timing Explorer (RXTE) data taken when the source was in the soft and transitional spectral states. We look at the power spectrum in the 0.01-50Hz range, using a model consisting of a cut-off power-law and two Lorentzian components. We are able to constrain the relation between the characteristic frequencies of the Lorentzian components, and show that it is consistent with a power-law relation having the same index (1.2) as previously reported for the hard state, but shifted by a factor ∼2. Furthermore, it is shown that the change in the frequency relation seen during the transitions can be explained by invoking a shift of one Lorentzian component to a higher harmonic, and we explore the possible support for this interpretation in the other component parameters. With the improved soft state results we study the evolution of the fractional variance for each temporal component. This approach indicates that the two Lorentzian components are connected to each other, and unrelated to the power-law component in the power spectrum, pointing to at least two separate emission components.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: binaries: close - stars: individual: Cyg X-1 - X-rays: binaries

VizieR on-line data: <Available at CDS (J/A+A/452/975): table1.dat>

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* GU Mus HXB 11 26 26.5947467816 -68 40 32.888148788           K3V-K7V 677 1
2 [GHJ2008] 3 HXB 16 50 00.980 -49 57 43.60     11.89     K4V 358 0
3 V* V821 Ara HXB 17 02 49.3810714542 -48 47 23.163091737 16.20 16.30 15.5     ~ 1826 0
4 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3997 0

    Equat.    Gal    SGal    Ecl

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