ANICERlook at the jet-like corona of MAXI J1535−571 through type-B quasi-periodic oscillations

Abstract

MAXI J1535−571 is a black-hole X-ray binary that in 2017 exhibited a very bright outburst which reached a peak flux of up to 5 Crab in the 2–20 keV band. Given the high flux, several X-ray space observatories obtained unprecedented high signal-to-noise data of key parts of the outburst. In our previous paper we studied the corona of MAXI J1535−571 in the hard-intermediate state (HIMS) with Insight-HXMT. In this paper we focus on the study of the corona in the soft-intermediate state (SIMS) through the spectral-timing analysis of 26 NICER detections of the type-B quasi-periodic oscillations (QPOs). From simultaneous fits of the energy, rms and lag spectra of these QPOs with our time-dependent Comptonization model, we find that in the SIMS the corona size is ∼ 6500 km and vertically extended. We detect a narrow iron line in the energy spectra, which we interpret to be due to the illumination of the outer part of the accretion disk by this large corona. We follow the evolution of the corona and the radio jet during the HIMS-SIMS transition, and find that the jet flux peaks after the time when the corona extends to its maximum vertical size. The jet flux starts to decay after the corona contracts vertically towards the black hole. This behavior points to a connection between the X-ray corona and the radio jet similar to that seen in other sources.

A variable corona during the transition from type-C to type-B quasi-periodic oscillations in the black hole X-ray binary MAXI J1820+070

“…Both for the type-C and type-B QPOs, the rms amplitude increases with energy up to the highest energy, similar to what is observed in other BHs, e.g., GX 339-4 (Zhang et al 2017), GRS 1915+105 (Zhang et al 2020Karpouzas et al 2021), MAXI J1535+571 (Huang et al 2018;Zhang et al 2022Zhang et al , 2023, and MAXI J1348-630 (Belloni et al 2020;Alabarta et al 2022;Liu et al 2022a). The large rms amplitude at energies above 10 keV (in some cases the rms amplitude of the QPO is ∼12% at 100-200 keV; Ma et al 2021) implies that the variability must be produced by the corona, given that neither the disc nor the reflection component contributessignificantly to the emission at those energies (e.g., Gilfanov 2010;Liu et al 2022a).…”

“…The parameters of the coronae indicate that, as in the HIMS, in the SIMS the small corona is also located inside the inner edge of the disc, whereas the vanishing small intrinsic feedback fraction indicates that the geometry of the large corona changes significantly. From all this we interpret that the radius of the large corona is in fact a characteristic size and that the large corona is vertically extended (see also, Méndez et al 2022;Zhang et al 2023). As in the HIMS, in the SIMS the temperature of the seed-photon source of the small corona is higher than that of the large corona.…”

“…This model is generically called vkompth 2 , and has been applied to the QPOs in a number of X-ray binaries to place constraints on the corona geometry of these systems. For example, the model was applied successfully to the kilohertz (kHz) QPOs in the neutron-star system 4U 1636−53 (Karpouzas et al 2020), the type-B QPO in the black-hole system MAXI J1348−630 (García et al 2021;Bellavita et al 2022), GX 339-4 (Peirano et al 2022, MAXI J1535-571 (Zhang et al 2023), and the type-C QPOs in GRS 1915+105 (Karpouzas et al 2021;García et al 2022;Méndez et al 2022) and MAXI J1535−571 (Zhang et al 2022;Rawat et al 2023). Here we apply this timedependent Comptonization model to the type-C and type-B QPOs in the black-hole system MAXI J1820+070 in the observation presented in Homan et al (2020).…”

Quasi-periodic Oscillations in GX 339−4 during the 2021 Outburst Observed with Insight-HXMT

“…The nearly flat lags in panels (a) and (b) around zero may be related to the lack of a Compton component, as the inner disk radius is large when the QPO frequency is small at the beginning (Ingram et al 2009), emitting fewer photons to the corona. In addition, the corona size may vary with QPO frequency (Zhang et al 2022(Zhang et al , 2023 and reach its minimum when the lags are approximately flat or zero, which is also confirmed in the source GRS 1915+105 using the spectraltiming Comptonization model (García et al 2022;Méndez et al 2022).…”

A Spectral-timing Study of the Inner Flow Geometry in MAXI J1535-571 with Insight-HXMT and NICER

“…A time-dependent Comptonization model, vKompth, was proposed by Karpouzas et al (2019) and Bellavita et al (2022), to explain the energy dependent rms and lag spectra of the QPOs and measure the corona geometry (Karpouzas et al 2021;Méndez et al 2022). From the measurements of this model, the corona geometry of BHTs can be slab-like or jet-like and connected to the jet behavior during the HIMS-to-SIMS transition in MAXI J1535-571 (Zhang et al 2022(Zhang et al , 2023Rawat et al 2023), MAXI J1348-630 (García et al 2020), andGX 339-4 (Peirano et al 2023).…”