J/ApJ/926/123 NIR variability of Cyg X-3 (Antokhin+, 2022)
Near-IR and X-ray variability of Cyg X-3: evidence for a compact IR source and
complex wind structures.
Antokhin I.I., Cherepashchuk A.M., Antokhina E.A., Tatarnikov A.M.
<Astrophys. J., 926, 123 (2022)>
=2022ApJ...926..123A 2022ApJ...926..123A
ADC_Keywords: Binaries, X-ray; Photometry, infrared; X-ray sources
Keywords: Wolf-Rayet stars ; High mass x-ray binary stars ; Black holes ;
Neutron stars ; Stellar mass loss ; Infrared photometry
Abstract:
We study near-infrared (JHK) and X-ray light curves of Cyg X-3
obtained with the 2.5m telescope of the Caucasian Mountain Observatory
of MSU SAI and collected from the RXTE ASM and MAXI archives. The
light curves in the X-ray and IR domains are strongly affected by
irregular variations. However, the mean curves are remarkably stable
and qualitatively similar in both domains. This means that the IR flux
of the system originates not only from the free-free radiation of the
Wolf-Rayet (WR) wind but also from a compact IR source located near
the relativistic companion. The shape of the mean X-ray and IR light
curves suggest the existence of two additional structures in the WR
wind-a bow shock near the relativistic companion and a so-called
"clumpy trail." Modeling of the mean X-ray and IR light curves allowed
us to obtain important system parameters: the orbital phase of the
superior conjunction of the relativistic companion
ph0=-0.066±0.006, the orbital inclination angle
i=29.5°±1.2°, and the WR mass-loss rate
dM/dt=(0.96±0.14)x10-5M☉/yr. By using relations between
dM/dt and the rate of the period change and between dM/dt and the WR
mass, we estimated the probable mass of the relativistic companion
MC∼7.2M☉, which points toward the black hole hypothesis.
However, this estimate is based on the assumption of a smooth WR wind.
Considering the uncertainty associated with clumping, the mass-loss
rate can be lower, which leaves room for the neutron star hypothesis.
Description:
Infrared photometry of Cyg X-3 was carried out in 2016 and 2017 at the
2.5m telescope of the Caucasian Mountain Observatory (CMO) of the
Lomonosov Moscow State University Sternberg State Astronomical
Institute (MSU SAI). The telescope is equipped with an infrared
camera-spectrograph ASTRONIRCAM. It was used in a photometric mode
with JHK bands of the Maunakea Observatories photometric system. A
total of 14 nights of observations were obtained.
To compare our IR data with the X-ray light curve of Cyg X-3, we used
the same RXTE ASM and MAXI data as in our previous paper (Antokhin &
Cherepashchuk 2019, J/ApJ/871/244).
Objects:
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RA (ICRS) DE Designation(s)
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20 32 25.77 +40 57 27.9 X Cyg X-3 = 2MASS J20322578+4057279
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 18 2790 Photometry in J band
table3.dat 18 413 Photometry in H band
table4.dat 19 1709 Photometry in K band
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)
J/MNRAS/308/473 : Cygnus X-3 IR spectra (Fender+, 1999)
J/MNRAS/373/781 : JHK photometry of faint standard stars (Leggett+, 2006)
J/MNRAS/406/307 : Radio variations of Cygnus X-3 (Koljonen+, 2010)
J/AJ/141/129 : Chandra Transmission Grating Data Cat. (Huenemoerder+, 2011)
J/BaltA/24/395 : X-ray and radio sources in binaries (Malkov+, 2015)
J/other/NewA/47.81 : Distances of X-ray binaries (Islam+, 2016)
J/ApJS/222/15 : WATCHDOG: all-sky database of Gal. BHXBs (Tetarenko+, 2016)
J/ApJ/871/244 : Times of X-ray minima & orbits of Cyg X-3 (Antokhin+, 2019)
J/A+A/640/A128 : Cygnus OB2 association NIR light curves (Roquette+, 2020)
J/ApJ/906/10 : Radio flares of Cygnus X-3 (Egron+, 2021)
J/A+A/645/A18 : SVOM-ECLAIRs known X-ray sources catalogue (Dagoneau+, 2021)
J/A+A/671/A149 : HMXBs in the Galaxy catalogue (Fortin+, 2023)
J/A+A/677/A134 : Galactic High Mass X-ray Binary catalogue (Neumann+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 F12.6 d MJD [57552.77/58016.98] Modified Julian date
14- 18 F5.3 mag var-c1 [2.49/4.39] Differential magnitude, J band (G1)
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.6 d MJD [58007.81/58016.98] Modified Julian date
14- 18 F5.3 mag var-c1 [1.26/1.74] Differential magnitude, H band (G1)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 12 F12.6 d MJD [57552.77/58016.98] Modified Julian date
14- 19 F6.3 mag var-c1 [-0.25/0.69] Differential magnitude, K band (G1)
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Global notes:
Note (G1): The differential magnitudes were calculated relative to the primary
2MASS comparison star c1=J20322359+4057156 (JMKO=12.283,
HMKO=11.700, KMKO=11.495).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Oct-2023