J/A+A/397/711 Comptonization and reflection in GRS 1915+105 (Rau+, 2003)
Comptonization and reflection of X-ray radiation and the X-ray-radio correlation
in the χ-states of GRS 1915+105.
Rau A., Greiner J.
<Astron. Astrophys. 397, 711 (2003)>
=2003A&A...397..711R 2003A&A...397..711R
ADC_Keywords: X-ray sources ; Binaries, X-ray
Keywords: X-ray: stars - stars: binaries: close -
X-rays: individual: GRS 1915+105
Abstract:
We present a comprehensive X-ray study of four years of pointed RXTE
observations of GRS 1915+105 in the χ-state. We interpret the
behavior of the hard power law tail spectrum as coming from inverse
Compton scattering of soft disk photons on a thermally dominated
hybrid corona above the accretion disk. GRS 1915+105 shows a strong,
variable reflection amplitude. As in other BHC and in Seyfert
galaxies, a correlation between the power law slope and the reflection
was found. Also, the radio fluxes at 2.25GHz and 15GHz correlate
with the power law slope, thus revealing a connection between the
outflowing matter and the comptonizing region in the χ-states.
Description:
Results of the analysis of 139 RXTE spectra of GRS 1915+105 in the
χ-state are shown. PCU0 of the Proportional Counter Array (PCA)
and High Energy X-Ray Timing Experiment (HEXTE) Cluster 0 data were
fitted in XSPEC 11.0 with a model consisting of of (i) photoelectric
absorption (WABS; Balucinska-Church & McGammon, 1992, Cat. VI/62),
(ii) a spectrum from an accretion disk consisting of multiple
blackbody components (DISKBB) and (iii) a power law spectrum reflected
from an ionized relativistic accretion disk (REFSCH; Fabian et al.,
1989MNRAS.238..729F 1989MNRAS.238..729F, Magdziarz & Zdziarski, 1995MNRAS.273..837M 1995MNRAS.273..837M).
Objects:
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RA (2000) DE Designation(s)
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19 15 11.5 +10 56 44 GRS 1915+105
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 161 139 Fitting results
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See also:
VI/62 : Photoelectric absorption cross-sections (Balucinska-Church+, 1992)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" Date Observational date
12- 21 F10.2 d JD Julian date
24- 27 I4 s Exp Exposure time
30- 33 I4 ct/s PCU0 Count rate in PCU0
36- 37 I2 ct/s H0 Count rate in Hexte cluster 0
40- 44 F5.2 keV kT Accretion disk temperature
47- 51 F5.2 keV E_kT Upper error of kT
53- 57 F5.2 keV e_kT Lower error of kT
59- 64 F6.2 --- Dbbno Accretion disk normalization (1)
66- 71 F6.2 --- E_Dbbno Upper error of Dbbno
73- 77 F5.2 --- e_Dbbno Lower error of Dbbno
80- 83 F4.2 --- Gamma Power law photon index (2)
86- 89 F4.2 --- E_Gamma Upper error of Gamma
92- 95 F4.2 --- e_Gamma Lower error of Gamma
97-101 F5.2 --- Refl Reflection amplitude
103-107 F5.2 --- E_Refl Upper error of Refl
109-113 F5.2 --- e_Refl Lower error of Refl
115-119 F5.1 ph/cm2/s/keV Kpo Power law normalization (2)
122-125 F4.1 ph/cm2/s/keV E_Kpo Upper error of Kpo
128-131 F4.1 ph/cm2/s/keV e_Kpo Lower error of Kpo
134-137 I4 --- xi Ionization parameter
140-143 I4 --- E_xi Upper error of xi
146-149 I4 --- e_xi Lower error pf xi
152-155 F4.2 --- c Factor for normalization of PCU0 and
Hexte Cluster 0
158-161 F4.2 --- chi2 Reduced chi-square
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Note (1): Dbbno = [ri/(D/10kpc)]2*cosθ , where
ri is the inner disk radius
Note (2): the Gamma index is such that
N(E) = Kpo (E/Eo)-Gamma
where N(E) = number of photons/keV/cm2/s,
Kpo = normalization for Eo = 1keV
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Acknowledgements: Arne Rau
(End) Arne Rau [MPE, Germany] 06-Oct-2002