The soft state of the black hole transient source MAXI J1820+070: emission from the edge of the plunge region?

Fabian, A. C.; Buisson, D. J. K.; Kosec, P.; Reynolds, C. S.; Wilkins, D. R.; Tomsick, John A.; Walton, D. J.; Gandhi, P.; Altamirano, D.; Arzoumanian, Zaven; Cackett, Edward M.; Dyda, Sergei; García, Javier A.; Gendreau, Keith C.; Grefenstette, Brian W.; Homan, J.; Kara, Erin; Ludlam, R. M.; Miller, J. M.; Steiner, James F.

doi:10.1093/mnras/staa564

Cited by 61 publications

(64 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This shows ( Figure 5) that the variability is greatest at high energy, where the emission is dominated by the power-law component. Similarly shaped variability spectra are also found in later observations of the soft state (Fabian et al 2020). The spectral shapes of the two stages are very similar but the flaring stage shows a higher amplitude (≈ 9% rather than ≈ 7%).…”

Section: Variability Spectrasupporting

confidence: 78%

“…This leaves significant residuals around 8 keV (χ 2 /(d.o.f.) = 1657/355 = 4.67 for the low flux state of the third stage/NuSTAR orbit), so we add an additional blackbody, as has been found in other observations of MAXI J1820+070 and interpreted as emission from the plunge region (Fabian et al 2020). This reduces the residuals to below 10% (χ 2 /(d.o.f.)…”

Section: Spectral Analysis -Full Observationmentioning

confidence: 97%

“…The jet ejecta were also observed in X-rays (Espinasse et al 2020). NuSTAR observations during the soft state are analysed in Fabian et al (2020), showing excess emission at energies above the disc emission, interpreted as emission from the plunge region inside the Innermost Stable Circular Orbit (ISCO). After around 80 days in the soft state, it returned to the hard state (Homan et al 2018c) while fading towards quiescence.…”

Section: Maxi J1820+070mentioning

confidence: 99%

See 2 more Smart Citations

MAXI J1820+070 with NuSTAR – II. Flaring during the hard to soft state transition with a long soft lag

Buisson

Fabian

Gandhi

et al. 2020

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

We continue the analysis of NuSTAR data from the recent discovery outburst of MAXI J1820+070 (optical counterpart ASASSN-18ey), focussing on an observation including unusual flaring behaviour during the hard to soft state transition, which is a short phase of outbursts and so comparatively rarely observed. Two plateaus in flux are separated by a variable interval lasting ∼10 ks, which shows dipping then flaring stages. The variability is strongest (with fractional variability up to $F_{\rm Var}\sim 10\%$) at high energies and reduces as the contribution from disc emission becomes stronger. Flux-resolved spectra show that the variability is primarily due to the power law flux changing. We also find a long soft lag of the thermal behind the power law emission, which is $20_{-1.2}^{+1.6}$ s during the flaring phase. The lag during the dipping stage has a different lag-energy spectrum, which may be due to a wave passing outwards through the disc. Time resolved spectral fitting suggests that the lag during the flaring stage may be due to the disc re-filling after being disrupted to produce the power law flare, perhaps related to the system settling after the jet ejection which occurred around 1 day before. The timescales of these phenomena imply a low viscosity parameter, α ∼ 10−3, for the inner region of the disc.

show abstract

Section: Variability Spectrasupporting

confidence: 78%

Section: Spectral Analysis -Full Observationmentioning

confidence: 97%

Section: Maxi J1820+070mentioning

confidence: 99%

See 1 more Smart Citation

MAXI J1820+070 with NuSTAR – II. Flaring during the hard to soft state transition with a long soft lag

Buisson

Fabian

Gandhi

et al. 2020

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…Spectral fits to NICER data of MAXI J1820 + 070 in the soft state suggests a low spin a < 0.5 (ref. 52 ). In order to study the effect of the low spin on the evolution of the corona, we refit six observations that cover the decay of this outburst with the same model, but fixing the spin a = 0.5.…”

Section: Discussionmentioning

confidence: 99%

Insight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070

You

Tuo

et al. 2021

Nat Commun

View full text Add to dashboard Cite

A black hole X-ray binary produces hard X-ray radiation from its corona and disk when the accreting matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contrast during the decay phase. We postulate a jet-like corona model, in which the corona can be understood as a standing shock where the material flowing through. In this dynamical scenario, the decrease of the reflection fraction is a signature of the corona’s bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster.

show abstract

“…The source later moved to the soft state (e.g. Fabian et al 2020). During the state transition, a change on the type of X-ray quasi-periodic oscillations was observed and immediately followed by the launch of a relativistic jet (Homan et al 2020;.…”

Section: Introductionmentioning

confidence: 99%

The Binary Mass Ratio in the Black Hole Transient MAXI J1820+070

Torres

Casares

Jiménez-Ibarra

et al. 2020

ApJL

119

View full text Add to dashboard Cite

We present intermediate resolution spectroscopy of the optical counterpart to the black hole X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained with the OSIRIS spectrograph on the 10.4-m Gran Telescopio Canarias. The observations were performed with the source close to the quiescent state and before the onset of renewed activity in August 2019. We make use of these data and K-type dwarf templates taken with the same instrumental configuration to measure the projected rotational velocity of the donor star. We find v rot sin i = 84±5 km s −1 (1−σ), which implies a donor to black-hole mass ratio q = M 2 /M 1 = 0.072 ± 0.012 for the case of a tidally locked and Roche-lobe filling donor star. The derived dynamical masses for the stellar components are M 1 = (5.95 ± 0.22) sin −3 i M and M 2 = (0.43 ± 0.08) sin −3 i M . The use of q, combined with estimates of the accretion disk size at the time of the optical spectroscopy, allows us to revise our previous orbital inclination constraints to 66 • < i < 81 • . These values lead to 95% confidence level limits on the masses of 5.73 < M 1 (M ) < 8.34 and 0.28 < M 2 (M ) < 0.77. Adopting instead the 63 ± 3 • orientation angle of the radio jet as the binary inclination leads to M 1 = 8.48 +0.79 −0.72 M and M 2 = 0.61 +0.13 −0.12 M (1−σ).

show abstract

The soft state of the black hole transient source MAXI J1820+070: emission from the edge of the plunge region?

Cited by 61 publications

References 28 publications

MAXI J1820+070 with NuSTAR – II. Flaring during the hard to soft state transition with a long soft lag

MAXI J1820+070 with NuSTAR – II. Flaring during the hard to soft state transition with a long soft lag

Insight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070

The Binary Mass Ratio in the Black Hole Transient MAXI J1820+070

Contact Info

Product

Resources

About