scholarly journals Hard X-ray emission from a Compton scattering corona in large black hole mass tidal disruption events

2021 ◽  
Author(s):  
Andrew Mummery ◽  
Steven A Balbus
Keyword(s):  
Black Hole ◽  
Numerical Models ◽  
Large Mass ◽  
Light Curves ◽  
State Transitions ◽  
P Value ◽  
Black Hole Mass ◽  
X Ray ◽  
Hard State ◽  
Black Hole Masses

Abstract We extend the relativistic time-dependent thin-disc TDE model to describe nonthermal (2 − 10 keV) X-ray emission produced by the Compton up-scattering of thermal disc photons by a compact electron corona, developing analytical and numerical models of the evolving nonthermal X-ray light curves. In the simplest cases, these X-ray light curves follow power-law profiles in time. We suggest that TDE discs act in many respects as scaled-up versions of XRB discs, and that such discs should undergo state transitions into harder accretion states. XRB state transitions typically occur when the disc luminosity becomes roughly one percent of its Eddington value. We show that if the same is true for TDE discs then this, in turn, implies that TDEs with nonthermal X-ray spectra should come preferentially from large-mass black holes. The characteristic hard-state transition mass is MHS ≃ 2 × 107M⊙. Hence, subpopulations of thermal and nonthermal X-ray TDEs should come from systematically different black hole masses. We demonstrate that the known populations of thermal and nonthermal X-ray TDEs do indeed come from different distributions of black hole masses. The null-hypothesis of identical black hole mass distributions is rejected by a two-sample Anderson-Darling test with a p-value <0.01. Finally, we present a model for the X-ray rebrightening of TDEs at late times as they transition into the hard state. These models of evolving TDE light curves are the first to join both thermal and nonthermal X-ray components in a unified scenario.

scholarly journals A minimal timescale for the continuum in 4U 1608-52 and Aql X-1

2021 ◽  
Vol 502 (1) ◽  
pp. L72-L78
Author(s):  
K Mohamed ◽  
E Sonbas ◽  
K S Dhuga ◽  
E Göğüş ◽  
A Tuncer ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Power Spectra ◽  
Light Curves ◽  
State Transitions ◽  
Strong Positive Correlation ◽  
Present Evidence ◽  
X Ray ◽  
X Ray Binaries ◽  
The Continuum

ABSTRACT Similar to black hole X-ray binary transients, hysteresis-like state transitions are also seen in some neutron-star X-ray binaries. Using a method based on wavelets and light curves constructed from archival Rossi X-ray Timing Explorer observations, we extract a minimal timescale over the complete range of transitions for 4U 1608-52 during the 2002 and 2007 outbursts and the 1999 and 2000 outbursts for Aql X-1. We present evidence for a strong positive correlation between this minimal timescale and a similar timescale extracted from the corresponding power spectra of these sources.

ON THE NATURE OF THE X-RAY CORONA OF BLACK HOLE BINARIES

2012 ◽  
Vol 08 ◽  
pp. 73-83 ◽  
Author(s):  
JULIEN MALZAC
Keyword(s):  
Black Hole ◽  
High Energy ◽  
State Transitions ◽  
Physical Parameters ◽  
X Ray ◽  
Black Hole Binaries ◽  
Accretion Flow ◽  
Recent Developments ◽  
Hard State ◽  
Radiation Processes

We discuss the nature of the X-ray emitting plasma of black hole binaries. It is well known that the temperature and optical depth of the Comptonising electrons of the X-ray corona of black hole binaries can be measured using spectroscopy in the 1 keV-1 MeV energy band. We emphasize recent developments in the modeling of high energy radiation processes which allow us to constrain other important physical parameters of the corona, such as the strength of magnetic field, or the temperature of the ions. The results appear to challenge current accretion models. In particular, standard advection dominated accretion flow do not match the observed properties of bright hard state X-ray binaries such as Cygnus X-1 or GX 339-4. On the other hand, we find that all the data would be consistent with a multi-zone magnetically dominated hot accretion flow model. We also emphasize that besides the usual spectral state transitions observed at luminosities above a few percent of Eddington, there is observational evidence for at least two additional, more subtle, radiative transitions occuring at lower luminosities.

scholarly journals Colors and patterns of black hole X-ray binary GX 339-4

2020 ◽  
Vol 638 ◽  
pp. A127
Author(s):  
Ilia A. Kosenkov ◽  
Alexandra Veledina ◽  
Valery F. Suleimanov ◽  
Juri Poutanen
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Near Infrared ◽  
Interstellar Extinction ◽  
State Transitions ◽  
Infrared Range ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Infrared Wavelengths

Black hole X-ray binaries show signs of nonthermal emission in the optical to near-infrared range. We analyzed optical to near-infrared SMARTS data on GX 339-4 over the 2002–2011 period. Using soft state data, we estimated the interstellar extinction toward the source and characteristic color temperatures of the accretion disk. We show that various spectral states of regular outbursts occupy similar regions on color-magnitude diagrams, and that transitions between the states proceed along the same tracks despite substantial differences in the morphology of the observed light curves. We determine the typical duration of hard-to-soft and soft-to-hard state transitions and the hard state at the decaying stage of the outburst to be one, two, and four weeks, respectively. We find that the failed outbursts cannot be easily distinguished from the regular outbursts at their early stages, but if the source reaches 16 mag in V band, it transits to the soft state. By subtracting the contribution of the accretion disk, we obtain spectra of the nonthermal component, which have constant, nearly flat shapes during the transitions between the hard and soft states. In contrast to the slowly evolving nonthermal component seen at optical and near-infrared wavelengths, the mid-infrared spectrum is strongly variable on short timescales and sometimes shows a prominent excess with a cutoff below 1014 Hz. We show that the radio to optical spectrum can be modeled using three components corresponding to the jet, hot flow, and irradiated accretion disk.

scholarly journals GRS 1758–258: RXTE Monitoring of a Rare Persistent Hard State Black Hole

10.14311/1480 ◽  
2011 ◽  
Vol 51 (6) ◽  
Author(s):  
M. Obst ◽  
K. Pottschmidt ◽  
A. Lohfink ◽  
J. Wilms ◽  
M. Böck ◽  
...  
Keyword(s):  
Black Hole ◽  
State Transitions ◽  
Spectral Evolution ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Long Term Behavior ◽  
X Ray Binaries ◽  
Black Hole Candidates

GRS 1758–258 is the least studied of the three persistent black hole X-ray binaries in our Galaxy. It is also one of only two known black hole candidates, including all black hole transients, which shows a decrease of its 3-10 keV flux when entering the thermally dominated soft state, rather than an increase.We present the spectral evolution of GRS 1758–258 from RXTE-PCA observations spanning a time of about 11 years from 1996 to 2007. During this time, seven dim soft states are detected. We also consider INTEGRAL monitoring observations of the source and compare the long-term behavior to that of the bright persistent black hole X-ray binary Cygnus X-1. We discuss the observed state transitions in the light of physical scenarios for black hole transitions.

scholarly journals Fitting along the Fundamental Plane: New comparisons of jet physics across the black hole mass scale

2010 ◽  
Vol 6 (S275) ◽  
pp. 250-254 ◽  
Author(s):  
Sera Markoff ◽  
Michael A. Nowak ◽  
Dipankar Maitra ◽  
Jörn Wilms ◽  
Elena Gallo ◽  
...  
Keyword(s):  
Black Hole ◽  
Mass Range ◽  
Mass Scale ◽  
Jet Physics ◽  
Black Hole Mass ◽  
Fundamental Plane ◽  
X Ray ◽  
Black Hole Accretion ◽  
Hard State ◽  
X Ray Binaries

AbstractCorrelations between the radio and X-ray bands in the hard state of black hole X-ray binaries (BHBs) have led to the discovery of the Fundamental Plane of black hole accretion, linking accretion-driven radiative attributes to black hole mass. Although this discovery has led to new constraints on radiative efficiencies, there is still significant degeneracy in terms of understanding the governing physics. I present several new results exploring the processes driving the Fundamental Plane over the black hole mass range. These include the first ever homogeneous fits of sources at approximately the same Eddington luminosity but millions of times different in mass, which I focus on for this proceeding article.

scholarly journals A NICER look at the state transitions of the black hole candidate MAXI J1535−571 during its reflares

2020 ◽  
Vol 496 (2) ◽  
pp. 1001-1012 ◽  
Author(s):  
V A Cúneo ◽  
K Alabarta ◽  
L Zhang ◽  
D Altamirano ◽  
M Méndez ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Timing Analysis ◽  
The State ◽  
State Transitions ◽  
X Ray ◽  
Black Hole Binaries ◽  
Black Hole Candidate ◽  
Hard State ◽  
Higher Sensitivity

ABSTRACT The black hole candidate and X-ray binary MAXI J1535−571 was discovered in 2017 September. During the decay of its discovery outburst, and before returning to quiescence, the source underwent at least four reflaring events, with peak luminosities of ∼1035–36 erg s−1 (d/4.1 kpc)2. To investigate the nature of these flares, we analysed a sample of NICER (Neutron star Interior Composition Explorer) observations taken with almost daily cadence. In this work, we present the detailed spectral and timing analysis of the evolution of the four reflares. The higher sensitivity of NICER at lower energies, in comparison with other X-ray detectors, allowed us to constrain the disc component of the spectrum at ∼0.5 keV. We found that during each reflare the source appears to trace out a q-shaped track in the hardness–intensity diagram similar to those observed in black hole binaries during full outbursts. MAXI J1535−571 transits between the hard state (valleys) and softer states (peaks) during these flares. Moreover, the Comptonized component is undetected at the peak of the first reflare, while the disc component is undetected during the valleys. Assuming the most likely distance of 4.1 kpc, we find that the hard-to-soft transitions take place at the lowest luminosities ever observed in a black hole transient, while the soft-to-hard transitions occur at some of the lowest luminosities ever reported for such systems.

scholarly journals Long-term variability of Swift J1753.5−0127: X-ray spectral–temporal correlations during state transitions

2019 ◽  
Vol 487 (1) ◽  
pp. 1439-1446
Author(s):  
Qingcui Bu ◽  
Lian Tao ◽  
Yu Lu ◽  
Shuangnan Zhang ◽  
Liang Zhang ◽  
...  
Keyword(s):  
Black Hole ◽  
Intermediate State ◽  
State Transition ◽  
Time Lag ◽  
Periodic Oscillation ◽  
State Transitions ◽  
Time Lags ◽  
X Ray ◽  
Hard State

ABSTRACT We studied the long-term evolution of the spectral–temporal correlated properties of the black hole candidate Swift J1753.5−0127 from the onset of its outburst until 2011 with the Rossi X-ray Timing Explorer (RXTE). The source stayed most of its lifetime during hard state, with occasionally transitioned to the hard intermediate state. Similar to typical black hole transients, Swift J1753.5−0127 traces a clear hard line in absolute rms–intensity diagram during the low hard state, with expected highest absolute rms, while shows a clear turn during the hard intermediate state, accompanied by lower absolute rms. Different from Cyg X-1, we found that frequency-dependent time lag increased significantly in the 0.02–3.2 Hz band during state transition in this source. The X-ray time lags in 0.02–3.2 Hz can therefore be used as indicators of state transition in this source. Type-C quasi-periodic oscillation frequency is positively related with its fractional rms and X-ray photon index, suggesting a moving inwards disc/corona scenario. We discussed the physical interpretation of our results in this paper.

scholarly journals NICER observations reveal that the X-ray transient MAXI J1348−630 is a black hole X-ray binary

2020 ◽  
Vol 499 (1) ◽  
pp. 851-861 ◽  
Author(s):  
L Zhang ◽  
D Altamirano ◽  
V A Cúneo ◽  
K Alabarta ◽  
T Enoto ◽  
...  
Keyword(s):  
Black Hole ◽  
State Transitions ◽  
Spectral Evolution ◽  
X Ray ◽  
Black Hole Candidate ◽  
Soft State ◽  
Intermediate States ◽  
Different Types ◽  
Hard State ◽  
Timing Properties

ABSTRACT We studied the outburst evolution and timing properties of the recently discovered X-ray transient MAXI J1348−630 as observed with NICER. We produced the fundamental diagrams commonly used to trace the spectral evolution, and power density spectra to study the fast X-ray variability. The main outburst evolution of MAXI J1348−630 is similar to that commonly observed in black hole transients. The source evolved from the hard state (HS), through hard- and soft-intermediate states, into the soft state in the outburst rise, and back to the HS in reverse during the outburst decay. At the end of the outburst, MAXI J1348−630 underwent two reflares with peak fluxes approximately one and two orders of magnitude fainter than the main outburst, respectively. During the reflares, the source remained in the HS only, without undergoing any state transitions, which is similar to the so-called ‘failed outbursts’. Different types of quasi-periodic oscillations (QPOs) are observed at different phases of the outburst. Based on our spectral-timing results, we conclude that MAXI J1348−630 is a black hole candidate.

scholarly journals X-ray spectral and flux variability of the microquasar GRS 1758−258 on timescales from weeks to years

2020 ◽  
Vol 636 ◽  
pp. A51 ◽  
Author(s):  
Maria Hirsch ◽  
Katja Pottschmidt ◽  
David M. Smith ◽  
Arash Bodaghee ◽  
Marion Cadolle Bel ◽  
...  
Keyword(s):  
Black Hole ◽  
Power Spectra ◽  
State Transitions ◽  
X Ray ◽  
Soft State ◽  
Term Variation ◽  
Transient Sources ◽  
Hard State ◽  
Proportional Counter Array

We present the spectral and timing evolution of the persistent black hole X-ray binary GRS 1758−258 based on almost 12 years of observations using the Rossi X-ray Timing Explorer Proportional Counter Array. While the source was predominantly found in the hard state during this time, it entered the thermally dominated soft state seven times. In the soft state GRS 1758−258 shows a strong decline in flux above 3 keV rather than the pivoting flux around 10 keV more commonly shown by black hole transients. In its 3–20 keV hardness intensity diagram, GRS 1758−258 shows a hysteresis of hard and soft state fluxes typical for transient sources in outburst. The RXTE-PCA and RXTE-ASM long-term light curves do not show any orbital modulations in the range of 2–30 d. However, in the dynamic power spectra significant peaks drift between 18.47 and 18.04 d for the PCA data, while less significant signatures between 19 d and 20 d are seen for the ASM data as well as for the Swift/BAT data. We discuss different models for the hysteresis behavior during state transitions as well as possibilities for the origin of the long term variation in the context of a warped accretion disk.

scholarly journals Exploring black hole scaling relations via the ensemble variability of Active Galactic Nuclei

2021 ◽  
Author(s):  
A Georgakakis ◽  
I Papadakis ◽  
M Paolillo
Keyword(s):  
Black Hole ◽  
Galactic Nuclei ◽  
Stellar Mass ◽  
Mass Relation ◽  
Black Hole Mass ◽  
X Ray ◽  
Mass Scaling ◽  
Spectrum Density ◽  
First Time ◽  
Black Hole Masses

Abstract An empirical model is presented that links, for the first time, the demographics of AGN to their ensemble X-ray variability properties. Observations on the incidence of AGN in galaxies are combined with (i) models of the Power Spectrum Density (PSD) of the flux variations of AGN and (ii) parameterisations of the black hole mass versus stellar-mass scaling relation, to predict the mean excess variance of active black hole populations in cosmological volumes. We show that the comparison of the model with observational measurements of the ensemble excess variance as a function of X-ray luminosity provides a handle on both the PSD models and the black hole mass versus stellar mass relation. We find strong evidence against a PSD model that is described by a broken power-law and a constant overall normalization. Instead our analysis indicates that the amplitude of the PSD depends on the physical properties of the accretion events, such as the Eddington ratio and/or the black hole mass. We also find that current observational measurements of the ensemble excess variance are consistent with the black hole mass versus stellar mass relation of local spheroids based on dynamically determined black hole masses. We also discuss future prospects of the proposed approach to jointly constrain the PSD of AGN and the black hole mass versus stellar mass relation as a function of redshift.

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