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

Abstract

The observed spectra from black hole (BH) X-ray binaries (XRBs) typically consist of two primary components: multitemperature blackbody (BB) originating from the accretion disk in soft X-ray, and a power-law like component in hard X-ray due to Comptonization of soft photons by the hot corona. Illumination of the disk by the corona gives rise to another key component known as reflection. A fraction of the incident hard X-ray radiation is naturally absorbed and re-emitted as a BB at lower energies, referred to as reprocessed BB. For densities relevant to XRBs and typical ionization values, the reprocessed BB may become significant in the soft X-ray region and should be noticeable in the observed spectra as a consequence of reflection. The absence of any BB component in the low/hard state of BH XRB may not be consistent with reflection of high irradiating flux observed as power-law from appropriately dense disk of XRB. We focus on the low/hard state of the BH XRB MAXI J1820+070. We simultaneously fit the shape and flux of the reflection spectra, allowing us to estimate the correct density and ionization of the slab and, correspondingly, the reprocessed BB. Our fitting suggests that the disk in principle may extend close to the BH and still the reprocessed BB due to disk illumination remains small enough to be consistent with the data as opposed to earlier study. The inner reflection component is highly ionized and its fit is primarily driven by its contribution to the continuum. The reprocessed BB cannot resolve whether the disk is extended close to the BH or not in the hard state. For this specific observation, the flux in inner reflection component turns out to be quite low with respect to outer reflection or power-law. Outflowing slab corona covering the inner region of the disk could be the possible geometry of the source with the underlying disk reaching close to the BH. (shortened)

14 pages (including 3 pages appendix), 6 figures, accepted for publication in A&A

References in corpus (34)

• X-ray Properties of Black-Hole Binaries
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• The corona contracts in a black-hole transient
• Towards precision measurements of accreting black holes using X-ray reflection spectroscopy
• X-ray reflection in accreting stellar-mass black hole systems
• An extremely powerful long-lived superluminal ejection from the black hole MAXI J1820+070
• A radio parallax to the black hole X-ray binary MAXI J1820+070
• The binary mass ratio in the black hole transient MAXI J1820+070
• Disk, Corona, Jet Connection in the Intermediate State of MAXI J1820+070 Revealed by NICER Spectral-Timing Analysis
• The Comptonisation of accretion disc X-ray emission: Consequences for X-ray reflection and the geometry of AGN coronae
• High Density Reflection Spectroscopy I. A case study of GX~339-4
• 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
• Polarized X-rays from windy accretion in Cygnus X-1
• Radius Constraints from Reflection Modeling of Cygnus X-2 with NuSTAR and NICER
• Dramatic Drop in the X-Ray Polarization of Swift J1727.8$-$1613 in the Soft Spectral State
• X-ray dips and a complex UV/X-ray cross-correlation function in the black hole candidate MAXI J1820+070
• A physical model for the broadband energy spectrum of X-ray illuminated accretion discs: fitting the spectral energy distribution of NGC 5548
• A spectral study of the black hole X-ray binary MAXI J1820+070 with AstroSat and NuSTAR
• Two major constraints on the inner radii of accretion disks
• NuSTAR monitoring of MAXI J1348-630: evidence of high density disc reflection
• First X-ray polarization measurement confirms the low black-hole spin in LMC X-3
• Does the disk in the hard state of XTE J1752-223 extend to the innermost stable circular orbit?
• High-density disc reflection spectroscopy of low-mass active galactic nuclei
• Spectral and polarization properties of reflected X-ray emission from black hole accretion discs
• Simultaneous NICER and NuSTAR Observations of the Ultra-compact X-ray Binary 4U 1543-624
• High-density reflection spectroscopy of black hole X-ray binaries in the hard state
• The Spin of New Black Hole Candidate: MAXI J1803-298 Observed by NuSTAR and NICER
• Photoionization Models for High Density Gas
• Impact of the reflection model on the estimate of the properties of accreting black holes
• The Donor of the Black-Hole X-Ray Binary MAXI J1820+070
• A multi-wavelength study of the hard and soft states of MAXI J1820+070 during its 2018 outburst
• A NuSTAR and Swift View of the Hard State of MAXI J1813-095

Cited by in corpus (2)

• Searching for quantum-gravity footprint around stellar-mass black holes
• Interaction between disk and extended corona in a general relativistic framework