J/ApJ/826/37 Fermi/GBM obs. of V404 Cygni 2015 outburst (Jenke+, 2016)
Fermi GBM observations of V404 Cyg during its 2015 outburst.
Jenke P.A., Wilson-Hodge C.A., Homan J., Veres P., Briggs M.S., Burns E.,
Connaughton V., Finger M.H., Hui M.
<Astrophys. J., 826, 37-37 (2016)>
=2016ApJ...826...37J 2016ApJ...826...37J (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, X-ray
Keywords: stars: black holes; X-rays: binaries
Abstract:
V404 Cygni was discovered in 1989 by the Ginga X-ray satellite during
its only previously observed X-ray outburst and soon after confirmed
as a black hole binary. On 2015 June 15, the Gamma-ray Burst Monitor
(GBM) triggered on a new outburst of V404 Cygni. We present 13 days of
GBM observations of this outburst, including Earth occultation flux
measurements and spectral and temporal analysis. The Earth occultation
fluxes reached 30 Crab with detected emission to 100keV and
determined, via hardness ratios, that the source was in a hard state.
At high luminosity, spectral analysis between 8 and 300keV showed that
the electron temperature decreased with increasing luminosity. This is
expected if the protons and electrons are in thermal equilibrium
during an outburst with the electrons cooled by the Compton scattering
of softer seed photons from the disk. However, the implied seed photon
temperatures are unusually high, suggesting a contribution from
another source, such as the jet. No evidence of state transitions is
seen during this time period. The temporal analysis reveals power
spectra that can be modeled with two or three strong, broad
Lorentzians, similar to the power spectra of black hole binaries in
their hard state.
Description:
The Gamma-ray Burst Monitor (GBM) triggered on V404 Cyg 169 times
between 2015 June 15-27.
Objects:
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RA (ICRS) DE Designation(s)
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20 24 03.83 +33 52 02.2 V404 Cyg = NOVA Cyg 1989
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 163 155 V404 Cyg spectral modeling results
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See also:
J/A+A/587/A61 : BlackCAT, stellar-mass BH in X-ray trans. (Corral-Santana+,
2016)
J/BaltA/24/395 : X-ray and radio sources in binaries (Malkov+, 2015)
J/ApJS/218/11 : The 5yr Fermi/GBM magnetar burst catalog (Collazzi+, 2015)
J/ApJS/216/32 : Localizations of GRBs with Fermi GBM (Connaughton+, 2015)
J/ApJ/800/17 : Mass-transfer sequences in 16 Galactic LMXBs (Fragos+, 2015)
J/A+A/564/A107 : Galactic ridge X-ray emission (Molaro+, 2014)
J/A+A/469/807 : Catalogue of Galactic low-mass X-ray binaries (Liu+, 2007)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- ID Event number
11- 13 I3 s Dur [8/726] Event selection duration
15- 18 F4.2 --- SpInd [0.06/1.7] Spectral index of cut-off
powerlaw model
20- 24 F5.2 --- e_SpInd ? Uncertainty in SpInd (1)
26- 31 F6.2 keV Ecut [7.5/148.2] Cut-Off energy of cut-off
powerlaw model
33- 38 F6.2 keV e_Ecut Uncertainty in Ecut
40- 44 F5.2 10+30W cutLum [3/76.4] Cut-off powerlaw model
10-1e3keV luminosity (2)
46- 50 F5.2 10+30W e_cutLum Uncertainty in cutLum
52- 55 F4.2 --- cutRChi [0.8/2.4] Reduced Χ2 of cut-off
powerlaw model
57- 60 F4.2 --- ref [1] Reflect*COMPTT model, fixed at Omega/2π
62- 67 F6.2 keV refkT [7.4/321] Reflect*COMPTT model electron temp
69- 73 F5.2 keV e_refkT ? Uncertainty in refkT (1)
75- 78 F4.2 keV refT0 [1] Reflect*COMPTT model, fixed photon seed temp
80- 85 F6.2 --- refTau [0.1/110] Reflect*COMPTT model Optical Depth
87- 91 F5.2 --- e_refTau ? Uncertainty in refTau (1)
93- 97 F5.2 10+30W refLum [3.6/75.6] Reflect*COMPTT model
10-1e3keV luminosity (2)
99-103 F5.2 10+30W e_refLum Uncertainty in refLum
105-108 F4.2 --- refChi [0.8/2.5] Reduced Χ2 of
Reflect*COMPTT model
110-116 F7.2 keV kT [10.9/3378] COMPTT model Electron temp
118-122 F5.2 keV e_kT ? Uncertainty in kT (1)
124-128 F5.2 keV T0 [1.9/11] COMPTT model photon seed temp
130-134 F5.2 keV e_T0 ? Uncertainty in T0 (1)
136-140 F5.2 --- Tau [0.05/16] COMPTT model optical depth
142-146 F5.2 --- e_Tau ? Uncertainty in Tau (1)
148-152 F5.2 10+30W Lum [3.6/77.2] COMPTT model 10-1e3keV luminosity (2)
154-158 F5.2 10+30W e_Lum Uncertainty in Lum
160-163 F4.2 --- RChi [0.8/2.1] Reduced Χ2 of COMPTT model
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Note (1): A blank value indicates that there is no error and the previous
column value is an upper limit.
Note (2): In units of 1e37erg/s.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Sep-2016