2019A&A...632A..40D


Query : 2019A&A...632A..40D

2019A&A...632A..40D - Astronomy and Astrophysics, volume 632A, 40-40 (2019/12-0)

The impact of thermal winds on the outburst lightcurves of black hole X-ray binaries.

DUBUS G., DONE C., TETARENKO B.E. and HAMEURY J.-M.

Abstract (from CDS):


Context. The observed signatures of winds from X-ray binaries are broadly consistent with thermal winds, which are driven by X-ray irradiation of the outer accretion disc. Thermal winds produce mass outflow rates that can exceed the accretion rate in the disc.
Aims. We aim to study the impact of thermal wind mass loss on the stability and lightcurves of black hole X-ray binaries subject to the thermal-viscous instability driving their outbursts. Strong mass loss could stop outbursts early, as proposed for the 2015 outburst of V404 Cyg.
Methods. We used an analytical model for thermal (Compton) wind mass loss as a function of radius, X-ray spectrum, and luminosity that was calibrated against numerical simulations. We also estimated the fraction of the X-rays, emitted close to the compact object, that are scattered back to the outer disc in the wind. Scattering in the thermal wind couples irradiation to the disc size and inner mass accretion rate. The disc evolution equations were modified to include this wind mass loss and the varying irradiation fraction.
Results. Scattering in the strong wind expected of long Porb systems enhances the irradiation heating of the outer disc, keeping it stable against the thermal-viscous instability. This accounts very well for the existence of persistently bright systems with large discs, such as Cyg X-2, 1E 1740.7-2942, or GRS 1758-258. Mass loss from the thermal wind shortens the outburst, as expected, but it is insufficient in explaining the rapid decay timescale of black-hole X-ray binary outbursts. However, including the wind-related varying irradiation fraction produces lightcurves with plateaus in long Porb systems like GRO J1655-40. Plateau lightcurves may be a dynamical signature of enhanced irradiation due to scattering in thermal winds.
Conclusions. Mass loss due to thermal winds is not a major driver for the outburst dynamics up to luminosities of 0.1-0.2LEdd. Higher luminosities may produce stronger mass loss but studying them is complicated since the wind becomes opaque. Magnetic winds, which extract angular momentum with little mass loss, seem more promising to explain the fast decay timescales generically seen in black-hole X-ray binaries. Thermal winds can play an important role in the outburst dynamics through the varying irradiation heating. This may be evidenced by relating changes in wind properties, X-ray spectra, or luminosity with changes in the optical emission that traces the outer disc. Simulations should enable more accurate estimates of the dependence of the irradiation onto the disc as a function of irradiation spectrum, radius, and disc wind properties.

Abstract Copyright: © G. Dubus et al. 2019

Journal keyword(s): accretion - accretion disks - binaries: close - stars: black holes - stars: winds - outflows - X-rays: binaries

Simbad objects: 16

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Number of rows : 16
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 V* KV UMa HXB 11 18 10.7930420496 +48 02 12.314730120     12.25     K5V-M1V 760 0
2 MAXI J1305-704 XB* 13 06 55.300 -70 27 05.11           ~ 50 0
3 CRTS J135716.8-093238 HXB 13 57 16.8357790008 -09 32 38.796487512           M4.5V 140 0
4 V* V1033 Sco HXB 16 54 00.137 -39 50 44.90   15.20 14.2 16.14   F5IV 1780 1
5 NAME Great Annihilator LXB 17 43 54.83 -29 44 42.6           ~ 653 1
6 SWIFT J174510.8-262411 LXB 17 45 10.849 -26 24 12.60           ~ 63 0
7 2XMM J180112.4-254436 LXB 18 01 12.40 -25 44 36.1           ~ 371 1
8 V* V4641 Sgr HXB 18 19 21.6343259256 -25 24 25.849595952     13.654   13.092 B9III 433 1
9 MAXI J1820+070 LXB 18 20 21.9423816480 +07 11 07.284859440           ~ 193 0
10 MAXI J1836-194 XB* 18 35 43.440 -19 19 10.48           ~ 123 0
11 V* V406 Vul HXB 18 58 41.580 +22 39 29.40 15.00 15.65 15.31     G5V-K0V 342 0
12 Granat 1915+105 HXB 19 15 11.55576 +10 56 44.9052           ~ 2433 0
13 HD 226868 HXB 19 58 21.6757355952 +35 12 05.784512688 9.38 9.72 8.91 8.42   O9.7Iabpvar 4092 0
14 V* V1408 Aql LXB 19 59 24.0074252040 +11 42 29.859773292 18.40 18.97 18.95 18.70 18.66 ~ 179 0
15 V* V404 Cyg HXB 20 24 03.8254458776 +33 52 01.962185735           G9/K0III/V 1174 0
16 V* V1341 Cyg LXB 21 44 41.1544345272 +38 19 17.066570988 15.00 15.13 14.68 15.00   A9III 1104 1

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2022.05.28-22:27:38

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