Interaction between disk and extended corona in a general relativistic framework

Abstract

The energy equilibrium between the corona and the underlying disk in a two-phase accretion flow sets a lower limit on the achievable photon index. A slab corona may not explain the hard state observations of X-ray binaries (XRBs). We incorporate energy feedback to the accretion disk resulting from illumination by an extended corona, and vice versa. The interaction between these two components allows for the possibility of finding an energetically self-consistent equilibrium solution for a given disk-corona system. We have upgraded the existing Monte Carlo radiative transfer code, MONK, to incorporate the interaction between the disk and the extended corona within the general relativistic framework. We introduce an albedo parameter to specify the fraction of the incident flux that is reflected by the disk, while the remainder is absorbed and added to the intrinsic dissipation. Reflection is modeled assuming a semi-infinite electron atmosphere. We find global equilibrium solutions by iterating interaction between disk and extended slab corona. A higher black hole spin, higher coronal temperature, and higher albedo all lead to harder spectra. For typical coronal temperatures and disk albedo, the lowest achievable photon index with a static slab corona fully covering the disk is approximately 1.7-1.8. With the upgraded version of MONK, we are now able to achieve global energy equilibrium for a given disk-corona system. This approach holds significant potential for constraining the coronal geometry using not only the observed flux but also polarization. A static slab does not appear to be a favorable coronal geometry for the hard state of XRBs, even when global energy balance is taken into account. In future work, we will explore truncated disk geometries and outflowing coronae as potential alternatives. (shortened)

Accepted for publication in A&A

References in corpus (40)

• X-ray reflected spectra from accretion disk models. III. A complete grid of ionized reflection calculations
• Multi-Temperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations
• X-ray reflected spectra from accretion disk models. I. Constant density atmospheres
• A Long, Hard Look at the Low-Hard State in Accreting Black Holes
• X-ray Polarization from Accreting Black Holes: II. The Thermal State
• High-Density Effects in X-ray Reflection Models from Accretion Disks
• Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
• Correlation between the photon index and X-ray luminosity of black hole X-ray binaries and active galactic nuclei: observations and interpretation
• The hard X-ray spectral evolution in X-ray binaries and its application to constrain the black hole mass of ultraluminous X-ray sources
• X-ray reflection in accreting stellar-mass black hole systems
• grmonty: a Monte Carlo Code for Relativistic Radiative Transport
• Multi-Temperature Blackbody Spectra of Thin Accretion Disks With and Without a Zero-Torque Inner Boundary Condition
• Two-temperature coronal flow above a thin disk
• MAXI J1820+070 with NuSTAR I. An increase in variability frequency but a stable reflection spectrum: coronal properties and implications for the inner disc in black hole binaries
• Analysis of NuSTAR and Suzaku observations of Cyg X-1 in the hard state: evidence for a truncated disc geometry
• Doughnut strikes sandwich: the geometry of hot medium in accreting black hole X-ray binaries
• Spectral analysis of the XMM-Newton data of GX 339-4 in the low/hard state: disc truncation and reflection
• Constraining the size of the corona with fully relativistic calculations of spectra of extended corona. I - the Monte Carlo radiative transfer code
• Self-Consistent Black Hole Accretion Spectral Models and the Forgotten Role of Coronal Comptonization of Reflection Emission
• Accretion Geometry in the Hard State of the Black-Hole X-Ray Binary MAXI J1820+070
• The evolution of GX 339-4 in the low-hard state as seen by NuSTAR and Swift
• The effects of a comptonizing corona on the appearance of the reflection components in accreting black hole spectra
• Origin of the X-ray disc-reflection steep radial emissivity
• A unified accretion-ejection paradigm for black hole X-ray binaries. IV. Replication of the 2010--2011 activity cycle of GX 339-4
• A physical model for the broadband energy spectrum of X-ray illuminated accretion discs: fitting the spectral energy distribution of NGC 5548
• Evolution of the accretion disk-corona during bright hard-to-soft state transition: A reflection spectroscopic study with GX 339-4
• Towards a complete description of spectra and polarization of black hole accretion disks: albedo profiles and returning radiation
• Two major constraints on the inner radii of accretion disks
• A spectral study of the black hole X-ray binary MAXI J1820+070 with AstroSat and NuSTAR
• Recovery of the X-ray polarisation of Swift J1727.8$-$1613 after the soft-to-hard spectral transition
• Stronger Reflection from Black Hole Accretion Disks in Soft X-ray States
• Full radiative coupling in two-phase models for accreting black holes
• Spin and Accretion Rate Dependence of Black Hole X-Ray Spectra
• Spectral and polarization properties of reflected X-ray emission from black hole accretion discs
• High-density reflection spectroscopy of black hole X-ray binaries in the hard state
• Analytical Model of Disk Evaporation and State Transitions in Accreting Black Holes
• A multi-wavelength study of the hard and soft states of MAXI J1820+070 during its 2018 outburst
• Towards more accurate synthetic reflection spectra: improving the calculations of returning radiation
• X-ray spectral correlations in a sample of Low-mass black hole X-ray binaries in the hard state
• Investigating the consistency of the shape and flux of X-ray reflection spectra in the hard state with an accretion disk reaching close to the black hole