Detection of a non-harmonic QPO precursor to Type-B in the HIMS of MAXI J1820+070 using NICER timing data.
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Broadband reflection spectroscopy of MAXI J1535-571 using AstroSat: Estimation of black hole mass and spin
19 Pith papers cite this work. Polarity classification is still indexing.
19
Pith papers citing it
abstract
We report the results from \textit{AstroSat} observations of the transient Galactic black hole X-ray binary MAXI J1535-571 during its hard-intermediate state of the 2017 outburst. We systematically study the individual and joint spectra from two simultaneously observing \textit{AstroSat} X-ray instruments, and probe and measure a number of parameter values of accretion disc, corona and reflection from the disc in the system using models with generally increasing complexities. Using our broadband ($1.3-70$ keV) X-ray spectrum, we clearly show that a soft X-ray instrument, which works below $\sim 10-12$ keV, alone cannot correctly characterize the Comptonizing component from the corona, thus highlighting the importance of broadband spectral analysis. By fitting the reflection spectrum with the latest version of the \textsc{relxill} family of relativistic reflection models, we constrain the black hole's dimensionless spin parameter to be $0.67^{+0.16}_{-0.04}$. We also jointly use the reflection spectral component (\textsc{relxill}) and a general relativistic thin disc component (\texttt{Kerrbb}), and estimate the black hole's mass and distance to be $10.39_{-0.62}^{+0.61} M_{\odot}$ and $5.4_{-1.1}^{+1.8}$ kpc respectively.
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representative citing papers
In 24 BHXRB outbursts, the thermal disk luminosity drops below the soft-state exponential decay baseline, and this deficit is used as a tracer of disk truncation, corroborated by decreasing timing frequencies.
Multi-dimensional simulations show that the parameter space for shocks in non-dissipative transonic sub-Keplerian accretion flows is substantially larger than the analytic prediction, with dynamic boundary layers producing outflows.
Fe Kα lines from accreting black holes are produced mostly outside 10 gravitational radii due to radial ionization gradients, allowing broad profiles without high spin.
Detection of an imaginary QPO in AT2019wey whose frequency drops from ~5 Hz to ~1 Hz with rising phase lags as the source transitions through HIMS and LHS, showing U-shaped phase-lag spectrum in HIMS.
Discovery and multiwavelength follow-up of EP J175257.3-351923, classified as a candidate black hole LMXB based on its 250-day FRED outburst, persistent hard state, truncated disk spectrum with ~217 keV cutoff, and flux ratios.
Simulations show magnetic field configurations set truncation radii and resonant cavities that produce QPO frequencies in thin disks matching black hole X-ray binary observations.
GRMHD simulations identify magnetic flux through the black hole horizon as the key variable setting jet efficiency and radiative output across MAD, INT, and SANE states, with mappings to temporal classes in GRS 1915+105 and other sources.
Stellar evolution and atmosphere models predict black hole progenitors are predominantly hot and blue with a direct-collapse rate of ~0.4 per century in a 1 Msun/yr star-forming galaxy.
Archival Chandra and XMM-Newton observations reveal two transient X-ray sources in NGC 4552 exceeding 10^39 erg/s, classifying them as new transient ULXs.
A transient ~11.2-hour optical QPO is detected in blazar PKS 0735+178 at 3-4 sigma significance using TESS sectors 71-72.
RGS spectra of V4641 Sgr reveal narrow N and O lines from a dense, multi-phase, photoionized disk atmosphere with log ξ ≈ 3.1 and 0.36 and velocities 540-720 km/s.
A multi-wavelength census of eRASS1 counterparts using ZTF photometry yields 43 refined COB candidates and 4 promising XRBs from radio cross-matches.
Comprehensive analysis of AstroSat data shows a sign change in QPO time lags at ~2 Hz for high-inclination sources, consistent with a transition from elongated jet-like to compact corona.
SKA+VLBI will deliver microarcsecond astrometry, polarimetry, and rapid multi-frequency imaging to track jets and accretion in X-ray binaries on AU scales.
Energy extraction via Comisso-Asenjo magnetic reconnection from rotating dyonic black holes in N=2 U(1)^2 gauged supergravity is possible but tightly limited by gauge coupling g and dyonic charges, peaking at intermediate spins rather than near-extremal.
AstroSat observation of MAXI J1535-571 reveals a tight correlation between QPO centroid frequency (1.7-3.0 Hz) and power-law index Gamma while flux increases linearly.
citing papers explorer
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Discovery of a quasi-periodic oscillation non-harmonically related to the Type-C QPO in the hard intermedidate state of MAXI J1820+070
Detection of a non-harmonic QPO precursor to Type-B in the HIMS of MAXI J1820+070 using NICER timing data.
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The disk luminosity deficit as a tracer of receding disk during Soft-to-Hard transitions in Black Hole X-ray Binaries
In 24 BHXRB outbursts, the thermal disk luminosity drops below the soft-state exponential decay baseline, and this deficit is used as a tracer of disk truncation, corroborated by decreasing timing frequencies.
-
Simulation based parameter space for shock in transonic, sub-Keplerian accretion flow onto non-rotating black holes
Multi-dimensional simulations show that the parameter space for shocks in non-dissipative transonic sub-Keplerian accretion flows is substantially larger than the analytic prediction, with dynamic boundary layers producing outflows.
-
Simulation-Based Prediction of Black Hole Fe K$\alpha$ Line Profiles
Fe Kα lines from accreting black holes are produced mostly outside 10 gravitational radii due to radial ionization gradients, allowing broad profiles without high spin.
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An atypical X-ray variability component in the black hole candidate AT2019wey
Detection of an imaginary QPO in AT2019wey whose frequency drops from ~5 Hz to ~1 Hz with rising phase lags as the source transitions through HIMS and LHS, showing U-shaped phase-lag spectrum in HIMS.
-
Discovery of EP J175257.3-351923 as a Candidate Black Hole Low-Mass X-ray Binary
Discovery and multiwavelength follow-up of EP J175257.3-351923, classified as a candidate black hole LMXB based on its 250-day FRED outburst, persistent hard state, truncated disk spectrum with ~217 keV cutoff, and flux ratios.
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Magnetic Configuration Imprints on Quasi-Periodic Variability in GRMHD Simulations of Thin Accretion Disks
Simulations show magnetic field configurations set truncation radii and resonant cavities that produce QPO frequencies in thin disks matching black hole X-ray binary observations.
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GRMHD Simulations of Magnetized Accretion Disk/Jet: Variabilities of Black Holes and Spectral Energy Distributions in Magnetic States
GRMHD simulations identify magnetic flux through the black hole horizon as the key variable setting jet efficiency and radiative output across MAD, INT, and SANE states, with mappings to temporal classes in GRS 1915+105 and other sources.
-
Hot blue progenitors of stellar-mass black holes
Stellar evolution and atmosphere models predict black hole progenitors are predominantly hot and blue with a direct-collapse rate of ~0.4 per century in a 1 Msun/yr star-forming galaxy.
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Transient and Variable Ultra-luminous X-ray Sources in NGC 4552
Archival Chandra and XMM-Newton observations reveal two transient X-ray sources in NGC 4552 exceeding 10^39 erg/s, classifying them as new transient ULXs.
-
Detection of Quasiperiodic Oscillations in the Blazar PKS 0735+178 with TESS
A transient ~11.2-hour optical QPO is detected in blazar PKS 0735+178 at 3-4 sigma significance using TESS sectors 71-72.
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Dense, multi-phase accretion disk atmosphere in the low-luminosity state of black hole transientV4641 Sgr
RGS spectra of V4641 Sgr reveal narrow N and O lines from a dense, multi-phase, photoionized disk atmosphere with log ξ ≈ 3.1 and 0.36 and velocities 540-720 km/s.
-
Hunting for Compact Object Binaries from eRASS1 Optical Counterparts through ZTF Time-domain Photometry and Multi-wavelength Census
A multi-wavelength census of eRASS1 counterparts using ZTF photometry yields 43 refined COB candidates and 4 promising XRBs from radio cross-matches.
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Understanding corona and disk evolution in black hole X-ray binaries through a comprehensive study of their broadband variability and QPO characteristics
Comprehensive analysis of AstroSat data shows a sign change in QPO time lags at ~2 Hz for high-inclination sources, consistent with a transition from elongated jet-like to compact corona.
-
Transforming X-ray Binary Astrophysics with SKA+VLBI
SKA+VLBI will deliver microarcsecond astrometry, polarimetry, and rapid multi-frequency imaging to track jets and accretion in X-ray binaries on AU scales.
-
Energy Extraction via Magnetic Reconnection from a Rotating Dyonic Black Hole in $N = 2, \ U(1)^2$ Gauged Supergravity
Energy extraction via Comisso-Asenjo magnetic reconnection from rotating dyonic black holes in N=2 U(1)^2 gauged supergravity is possible but tightly limited by gauge coupling g and dyonic charges, peaking at intermediate spins rather than near-extremal.
-
Spectro-timing analysis of MAXI J1535-571 using AstroSat
AstroSat observation of MAXI J1535-571 reveals a tight correlation between QPO centroid frequency (1.7-3.0 Hz) and power-law index Gamma while flux increases linearly.
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