J/ApJ/808/144 Swift/XRT 0.5-10keV obs. of MAXI J1659-152 (Kalamkar+, 2015)
Swift X-ray telescope study of the black hole binary MAXI J1659-152:
variability from a two component accretion flow.
Kalamkar M., van der Klis M., Heil L., Homan J.
<Astrophys. J., 808, 144 (2015)>
=2015ApJ...808..144K 2015ApJ...808..144K (SIMBAD/NED BibCode)
ADC_Keywords: X-ray sources ; Binaries, X-ray
Keywords: accretion, accretion disks; X-rays: binaries;
X-rays: individual: MAXI J1659-152
Abstract:
We present an energy dependent X-ray variability study of the 2010
outburst of the black hole X-ray binary MAXI J1659-152 with the Swift
X-ray Telescope (XRT). The broadband noise components and the
quasi-periodic oscillations (QPO) observed in the power spectra show a
strong and varied energy dependence. Combining Swift XRT data with
data from the Rossi X-ray Timing Explorer, we report, for the first
time, an rms spectrum (fractional rms amplitude as a function of
energy) of these components in the 0.5-30keV energy range. We find
that the strength of the low-frequency component (<0.1Hz) decreases
with energy, contrary to the higher frequency components (>0.1Hz)
whose strengths increase with energy. In the context of the
propagating fluctuations model for X-ray variability, we suggest that
the low-frequency component originates in the accretion disk (which
dominates emission below ∼2keV) and the higher frequency components
are formed in the hot flow (which dominates emission above ∼2keV). As
the properties of the QPO suggest that it may have a different driving
mechanism, we investigate the Lense-Thirring precession of the hot
flow as a candidate model. We also report on the QPO coherence
evolution for the first time in the energy band below 2keV. While
there are strong indications that the QPO is less coherent at energies
below 2keV than above 2keV, the coherence increases with intensity
similar to what is observed at energies above 2keV in other black hole
X-ray binaries.
Description:
We analyzed all 38 observations taken in Windowed Timing (WT) mode
with the XRT on board the Swift satellite between 2010 September 25
(MJD 55464) and 2010 October 22 (MJD 55491).
For comparison, we also use the results from the first 47 RXTE
observations taken between September 28, 2010 (MJD 55467) and October
22, 2010 (MJD 55491), the same period as the XRT observations, in the
2-60keV energy band as previously presented in Kalamkar et al.
(2011ApJ...731L...2K 2011ApJ...731L...2K).
Objects:
-------------------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------------------
16 59 01.71 -15 15 28.5 MAXI J1659-152 = MAXI J1659-152
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 70 108 *Swift observations
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Note on table2.dat: The Time of the observation, the Swift observation ID,
the frequency, and fractional rms amplitude in the 0.5-2 and 2-10keV bands of
the lfn, the break (only when present and is indicated with a "*"),
the quasi-periodic oscillation (QPO), and the hump components, respectively.
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See also:
B/cb : Cataclysmic Binaries, LMXBs, and related objects (Ritter+, 2014)
J/ApJS/209/14 : The Swift/BAT hard X-ray transient monitor (Krimm+, 2013)
J/A+A/545/A27 : INTEGRAL/IBIS 9-year Galactic Hard X-Ray Survey (Krivonos+,
2012)
J/MNRAS/426/1701 : High-frequency QPO in black hole binaries (Belloni+, 2012)
J/MNRAS/415/292 : MAXI J1659-152 2010 outburst analysis (Munoz-Darias+, 2011)
J/A+A/452/975 : Temporal variability of Cygnus X-1 (Axelsson+, 2006)
J/A+A/407/1039 : X-ray power spectra of Cygnus X-1 (Pottschmidt+, 2003)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian Date of the observation (1)
11 A1 --- f_MJD [*] *: break
13- 23 I11 --- ObsID Swift observation identifier
25- 29 F5.3 Hz nuSoft [0.007/1.2]? Soft 0.5-2 keV band frequency
31- 35 F5.3 Hz e_nuSoft [0.002/0.1]? Uncertainty in nuSoft
37- 41 F5.2 % rmsSoft [2.6/24.5]? Soft 0.5-2 keV band fractional
rms amplitude
43- 46 F4.2 % e_rmsSoft [0.3/2]? Uncertainty in rmsSoft
48- 52 F5.3 Hz nuHard [0.01/3.7]? Hard 2-10 keV band frequency
54- 58 F5.3 Hz e_nuHard [0.003/1.1]? Uncertainty in nuHard
60- 64 F5.2 % rmsHard [5.6/26]? Hard 2-10 keV band fractional
rms amplitude
66- 70 F5.3 % e_rmsHard [0.09/2.1]? Uncertainty in rmsHard
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Note (1): The first four observations show the parameters in multiple
Good Time Intervals (GTIs).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Dec-2015