scholarly journals Joint XMM-Newton and NuSTAR observations of the reflection spectrum of III Zw 2

2020 ◽  
Vol 635 ◽  
pp. A172 ◽  
Author(s):  
Wara Chamani ◽  
Karri Koljonen ◽  
Tuomas Savolainen
Keyword(s):  
Black Hole ◽  
Reflection Spectrum ◽  
Main Tool ◽  
Radio Flux ◽  
X Ray ◽  
Accretion Flow ◽  
Emission Component ◽  
Reflection Model ◽  
Wide Range ◽  
Reflection Component

Detecting and modeling the reprocessed hard X-ray emission component in the accretion flow, the so-called reflection spectrum, is a main tool used to estimate black hole spins in a wide range of astrophysical black holes, regardless of their mass or distance. In this work, we study the X-ray spectra of the Seyfert I galaxy III Zw 2 by using multiepoch XMM-Newton, NuSTAR, and Suzaku observations. The X-ray spectra exhibit a soft-excess below 1 keV and a prominent excess at the location of the broad Fe Kα line at 6.4 keV. To account for these spectral features, we fit the spectra with multiple models including an ionized partially covering absorber and an accretion disk reflection model. To fully resolve the reflection component, we analyzed jointly the XMM-Newton and NuSTAR observations taken in 2017 and archival XMM-Newton data from 2000. Assuming the reflection scenario, the resulting model fits support for a rapidly spinning black hole (a ≥ 0.98) in this radio-intermediate source. The X-ray spectra in 2000 and 2017 are remarkably similar; the only difference pertains to the reflection fraction, which is possibly due to a change in the geometry of the accretion flow. However, the Suzaku observation is markedly different, and we suggest this could be an effect of a jet contribution in the X-ray band, which is supported by the elevated radio flux during this observation.

scholarly journals A detailed study on the reflection component for the black hole candidate MAXI J1836−194

2020 ◽  
Vol 493 (2) ◽  
pp. 2178-2187
Author(s):  
Yanting Dong ◽  
Javier A García ◽  
Zhu Liu ◽  
Xueshan Zhao ◽  
Xueying Zheng ◽  
...  
Keyword(s):  
Black Hole ◽  
Spectral Analysis ◽  
Primary Source ◽  
Ionization State ◽  
X Ray ◽  
Black Hole Candidate ◽  
Reflection Model ◽  
Iron Abundance ◽  
Reflection Component ◽  
Ionization Gradient

ABSTRACT We present a detailed spectral analysis of the black hole candidate MAXI J1836−194. The source was caught in the intermediate state during its 2011 outburst by Suzaku and RXTE. We jointly fit the X-ray data from these two missions using the relxill model to study the reflection component, and a steep inner emissivity profile indicating a compact corona as the primary source is required in order to achieve a good fit. In addition, a reflection model with a lamp-post configuration (relxilllp), which is normally invoked to explain the steep emissivity profile, gives a worse fit and is excluded at 99 per cent confidence level compared to relxill. We also explore the effect of the ionization gradient on the emissivity profile by fitting the data with two relativistic reflection components, and it is found that the inner emissivity flattens. These results may indicate that the ionization state of the disc is not constant. All the models above require a supersolar iron abundance higher than ∼4.5. However, we find that the high-density version of reflionx can describe the same spectra even with solar iron abundance well. A moderate rotating black hole (a* = 0.84–0.94) is consistently obtained by our models, which is in agreement with previously reported values.

scholarly journals The X-ray corona turns into the relativistic jet in the micro quasar GRS 1915+105

2021 ◽  
Author(s):  
Mariano Mendez ◽  
Konstantinos Karpouzas ◽  
Federico Garcia ◽  
Liang Zhang ◽  
Yuexin Zhang ◽  
...  
Keyword(s):  
Black Hole ◽  
High Frequency ◽  
High Energy ◽  
Radio Flux ◽  
High Energy Part ◽  
Iron Line ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Accretion Flow ◽  
High Frequency Variability

Abstract GRS 1915+1051 was the first stellar-mass black-hole in our Galaxy to display a superluminal radio jet2, similar to those observed in active galactic nuclei with a supermassive black hole at the centre3. It has been proposed that the radio emission in GRS 1915+105 is fed by instabilities in the accretion disc4 by which the inner parts of the accretion flow is ejected in the jet5–7. Here we show that there is a significant correlation between: (i) the radio flux, coming from the jet, and the flux of the iron emission line, coming from the disc and, (ii) the temperature of the corona that produces the high-energy part of the X-ray spectrum via inverse Compton scattering and the amplitude of a high-frequency variability component coming from the innermost part of the accretion flow. At the same time, the radio flux and the flux of the iron line are strongly anti-correlated with the temperature of the X-ray corona and the amplitude of the high-frequency variability component. These correlations persist over ~10 years, despite the highly variable X-ray and radio properties of the source in that period8,9. Our findings provide, for the first time, incontrovertible evidence that the energy that powers this black-hole system can be directed either to the X-ray corona or the jet. When this energy is used to power the corona, raising its temperature, there is less energy left to fuel the jet and the radio flux drops, and vice versa. These facts, plus the modelling of the variability in this source show conclusively that in GRS 1915+105 the X-ray corona morphs into the jet.

scholarly journals Radiative efficiency of hot accretion flow and the radio/X-ray correlation in X-ray binaries

2014 ◽  
Vol 10 (S312) ◽  
pp. 139-140
Author(s):  
Fu-Guo Xie
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Rate ◽  
Galactic Nuclei ◽  
X Ray ◽  
Radiative Efficiency ◽  
Accretion Flow ◽  
Accretion Rates ◽  
Distinctive Property ◽  
X Ray Binaries

AbstractSignificant progresses have been made since the discovery of hot accretion flow, a theory successfully applied to the low-luminosity active galactic nuclei (LLAGNs) and black hole (BH) X-ray binaries (BHBs) in their hard states. Motivated by these updates, we re-investigate the radiative efficiency of hot accretion flow. We find that, the brightest regime of hot accretion flow shows a distinctive property, i.e. it has a constant efficiency independent of accretion rates, similar to the standard thin disk. For less bright regime, the efficiency has a steep positive correlation with the accretion rate, while for faint regime typical of advection-dominated accretion flow, the correlation is shadower. This result can naturally explain the observed two distinctive correlations between radio and X-ray luminosities in black hole X-ray binaries. The key difference in systems with distinctive correlations could be the viscous parameter, which determines the critical luminosity of different accretion modes.

scholarly journals The Lx–Luv–Lradio relation and corona–disc–jet connection in optically selected radio-loud quasars

2020 ◽  
Vol 496 (1) ◽  
pp. 245-268 ◽  
Author(s):  
S F Zhu (朱世甫) ◽  
W N Brandt ◽  
B Luo (罗斌) ◽  
Jianfeng Wu (武剑锋) ◽  
Y Q Xue (薛永泉) ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Small Scale ◽  
Spectral Slope ◽  
Physical Processes ◽  
X Ray ◽  
Accretion Flow ◽  
Radio Jets ◽  
Spectrum Radio ◽  
Uniform Sample

ABSTRACT Radio-loud quasars (RLQs) are more X-ray luminous than predicted by the X-ray–optical/UV relation (i.e. $L_\mathrm{x}\propto L_\mathrm{uv}^\gamma$) for radio-quiet quasars (RQQs). The excess X-ray emission depends on the radio-loudness parameter (R) and radio spectral slope (αr). We construct a uniform sample of 729 optically selected RLQs with high fractions of X-ray detections and αr measurements. We find that steep-spectrum radio quasars (SSRQs; αr ≤ −0.5) follow a quantitatively similar $L_\mathrm{x}\propto L_\mathrm{uv}^{\gamma }$ relation as that for RQQs, suggesting a common coronal origin for the X-ray emission of both SSRQs and RQQs. However, the corresponding intercept of SSRQs is larger than that for RQQs and increases with R, suggesting a connection between the radio jets and the configuration of the accretion flow. Flat-spectrum radio quasars (FSRQs; αr > −0.5) are generally more X-ray luminous than SSRQs at given Luv and R, likely involving more physical processes. The emergent picture is different from that commonly assumed where the excess X-ray emission of RLQs is attributed to the jets. We thus perform model selection to compare critically these different interpretations, which prefers the coronal scenario with a corona–jet connection. A distinct jet component is likely important for only a small portion of FSRQs. The corona–jet, disc–corona, and disc–jet connections of RLQs are likely driven by independent physical processes. Furthermore, the corona–jet connection implies that small-scale processes in the vicinity of supermassive black holes, probably associated with the magnetic flux/topology instead of black hole spin, are controlling the radio-loudness of quasars.

scholarly journals A broad-band X-ray spectral study of the Seyfert 1 galaxy ESO 141–G055 with XMM–Newton and NuSTAR

2020 ◽  
Vol 497 (4) ◽  
pp. 4213-4221
Author(s):  
Ritesh Ghosh ◽  
Sibasish Laha
Keyword(s):  
Black Hole ◽  
Spectral Study ◽  
Column Density ◽  
Broad Band ◽  
Accretion Disc ◽  
Physical Models ◽  
X Ray ◽  
Reflection Model ◽  
Ionization Parameter

ABSTRACT We have extensively studied the broad--band X-ray spectra of the source ESO 141–G055 using all available XMM–Newton and NuSTAR observations. We detect a prominent soft excess below $2\rm \, \, {\rm keV}$, a narrow Fe line, and a Compton hump ($\gt 10\rm \, \, {\rm keV}$). The origin of the soft excess is still debated. We used two models to describe the soft excess: the blurred reflection from the ionized accretion disc and the intrinsic thermal Comptonization model. We find that both of these models explain the soft excess equally well. We confirm that we do not detect any broad Fe line in the X-ray spectra of this source, although both the physical models prefer a maximally spinning black hole scenario (a > 0.96). This may mean that either the broad Fe line is absent or blurred beyond detection. The Eddington rate of the source is estimated to be $\lambda _{\rm \, Edd}\sim 0.31$. In the reflection model, the Compton hump has a contribution from both ionized and neutral reflection components. The neutral reflector which simultaneously describes the narrow Fe K α and the Compton hump has a column density of $N_{\rm H} \ge 7\times 10^{24} \, \rm cm^{-2}$. In addition, we detect a partially covering ionized absorption with ionization parameter $\log \xi /\rm \, erg\, cm\, s^{-1}$  = $0.1^{+0.1}_{-0.1}$ and column density $N_{\rm H} =20.6^{+1.0}_{-1.0}\times 10^{22} \, \rm cm^{-2}$ with a covering factor of $0.21^{+0.01}_{-0.01}$.

scholarly journals Swift/XRT, Chandra, and XMM–Newton observations of IGR J17091–3624 as it returns into quiescence

2020 ◽  
Vol 497 (1) ◽  
pp. 1115-1126
Author(s):  
M Pereyra ◽  
D Altamirano ◽  
J M C Court ◽  
N Degenaar ◽  
R Wijnands ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Time Scales ◽  
Strong Evidence ◽  
Spectral Properties ◽  
X Ray ◽  
Term Evolution ◽  
Wide Range ◽  
Low Mass

ABSTRACT IGR J17091–3624 is a low-mass X-ray binary (LMXB), which received wide attention from the community thanks to its similarities with the bright black hole system GRS 1915+105. Both systems exhibit a wide range of highly structured X-ray variability during outburst, with time-scales from few seconds to tens of minutes, which make them unique in the study of mass accretion in LMXBs. In this work, we present a general overview into the long-term evolution of IGR J17091–3624, using Swift/XRT observations from the onset of the 2011–2013 outburst in 2011 February till the end of the last bright outburst in 2016 November. We found four re-flares during the decay of the 2011 outburst, but no similar re-flares appear to be present in the latter one. We studied, in detail, the period with the lowest flux observed in the last 10 yr, just at the tail end of the 2011–2013 outburst, using Chandra and XMM-Newton observations. We observed changes in flux as high as a factor of 10 during this period of relative quiescence, without strong evidence of softening in the spectra. This result suggests that the source has not been observed at its true quiescence so far. By comparing the spectral properties at low luminosities of IGR J17091–3624 and those observed for a well-studied population of LMXBs, we concluded that IGR J17091–3624 is most likely to host a black hole as a compact companion rather than a neutron star.

scholarly journals The MAVERIC survey: a hidden pulsar and a black hole candidate in ATCA radio imaging of the globular cluster NGC 6397

2020 ◽  
Vol 493 (4) ◽  
pp. 6033-6049 ◽  
Author(s):  
Yue Zhao ◽  
Craig O Heinke ◽  
Vlad Tudor ◽  
Arash Bahramian ◽  
James C A Miller-Jones ◽  
...  
Keyword(s):  
Black Hole ◽  
Globular Cluster ◽  
Radio Observation ◽  
Millisecond Pulsar ◽  
Radio Flux ◽  
X Ray ◽  
Black Hole Candidate ◽  
Radio Imaging ◽  
Low Mass ◽  
Compact Array

ABSTRACT Using a 16.2-h radio observation by the Australia Telescope Compact Array and archival Chandra data, we found >5σ radio counterparts to four known and three new X-ray sources within the half-light radius (rh) of the Galactic globular cluster NGC 6397. The previously suggested millisecond pulsar (MSP) candidate, U18, is a steep-spectrum (Sν ∝ να; $\alpha =-2.0^{+0.4}_{-0.5}$) radio source with a 5.5-GHz flux density of 54.7 ± 4.3 $\mu \mathrm{ Jy}$. We argue that U18 is most likely a ‘hidden’ MSP that is continuously hidden by plasma shocked at the collision between the winds from the pulsar and companion star. The non-detection of radio pulsations so far is probably the result of enhanced scattering in this shocked wind. On the other hand, we observed the 5.5-GHz flux of the known MSP PSR J1740−5340 (U12) to decrease by a factor of >2.8 during epochs of 1.4-GHz eclipse, indicating that the radio flux is absorbed in its shocked wind. If U18 is indeed a pulsar whose pulsations are scattered, we note the contrast with U12’s flux decreases in eclipse, which argues for two different eclipse mechanisms at the same radio frequency. In addition to U12 and U18, we also found radio associations for five other Chandra X-ray sources, four of which are likely background galaxies. The last, U97, which shows strong H α variability, is mysterious; it may be either a quiescent black hole low-mass X-ray binary or something more unusual.

scholarly journals A spectral study of the black hole X-ray binary MAXI J1820+070 with AstroSat and NuSTAR

2020 ◽  
Vol 498 (4) ◽  
pp. 5873-5884
Author(s):  
Sudip Chakraborty ◽  
Nilam Navale ◽  
Ajay Ratheesh ◽  
Sudip Bhattacharyya
Keyword(s):  
Black Hole ◽  
Broad Band ◽  
X Ray ◽  
Reflection Model ◽  
Temporal Features ◽  
Source State ◽  
Hard State ◽  
Independent Observations ◽  
Best Fitting ◽  
Fitting Model

ABSTRACT MAXI J1820+070 is a newly discovered transient black hole X-ray binary, which showed several spectral and temporal features. In this work, we analyse the broad-band X-ray spectra from all three simultaneously observing X-ray instruments onboard AstroSat, as well as contemporaneous X-ray spectra from NuSTAR, observed during the hard state of MAXI J1820+070 in 2018 March. Implementing a combination of multicolour disc model, relativistic blurred reflection model relxilllpcp, and a distant reflection in the form of xillvercp, we achieve reasonable and consistent fits for AstroSat and NuSTAR spectra. The best-fitting model suggests a low temperature disc (kTin ∼ 0.3 keV), iron overabundance (AFe ∼ 4–5 solar), a short lamp-post corona height (h ≲ 8Rg), and a high corona temperature (kTe ∼ 115–150 keV). Addition of a second Comptonization component leads to a significantly better fit, with the kTe of the second Comptonization component being ∼14–18 keV. Our results from independent observations with two different satellites in a similar source state indicate an inhomogeneous corona, with decreasing temperature attributed to increasing height. Besides, utilizing the broader energy coverage of AstroSat, we estimate the black hole mass to be 6.7–13.9 M⊙, consistent with independent measurements reported in the literature.

scholarly journals Inferring black hole spins and probing accretion/ejection flows in AGNs with the Athena X-ray Integral Field Unit

2019 ◽  
Vol 628 ◽  
pp. A5 ◽  
Author(s):  
Didier Barret ◽  
Massimo Cappi
Keyword(s):  
Black Hole ◽  
Extreme Values ◽  
Model Parameters ◽  
Gravitational Radius ◽  
Detailed Model ◽  
Spin Geometry ◽  
X Ray ◽  
Field Unit ◽  
Reflection Component ◽  
Integral Field

Context. Active galactic nuclei (AGNs) display complex X-ray spectra that exhibit a variety of emission and absorption features. These are commonly interpreted as a combination of (i) a relativistically smeared reflection component, resulting from the irradiation of an accretion disk by a compact hard X-ray source; (ii) one or several warm or ionized absorption components produced by AGN-driven outflows crossing our line of sight; and (iii) a nonrelativistic reflection component produced by more distant material. Disentangling these components via detailed model fitting could be used to constrain the black hole spin, geometry, and characteristics of the accretion flow, as well as of the outflows and surroundings of the black hole. Aims. We investigate how a high-throughput high-resolution X-ray spectrometer such as the Athena X-ray Integral Field Unit (X-IFU) can be used to this aim, using the state-of-the-art reflection model relxill in a lamp-post geometrical configuration. Methods. We simulated a representative sample of AGN spectra, including all necessary model complexities, as well as a range of model parameters going from standard to more extreme values, and considered X-ray fluxes that are representative of known AGN and quasar populations. We also present a method to estimate the systematic errors related to the uncertainties in the calibration of the X-IFU. Results. In a conservative setting, in which the reflection component is computed self consistently by the relxill model from the pre-set geometry and no iron overabundance, the mean errors on the spin and height of the irradiating source are < 0.05 and ∼0.2 Rg (in units of gravitational radius). Similarly, the absorber parameters (column density, ionization parameter, covering factor, and velocity) are measured to an accuracy typically less than ∼5% over their allowed range of variations. Extending the simulations to include blueshifted ultra-fast outflows, we show that X-IFU could measure their velocity with statistical errors < 1%, even for high-redshift objects (e.g., at redshifts ∼2.5). Conclusion. The simulations presented here demonstrate the potential of the X-IFU to understand how black holes are powered and how they shape their host galaxies. The accuracy in recovering the physical model parameters encoded in their X-ray emission is reached thanks to the unique capability of X-IFU to separate and constrain narrow and broad emission and absorption components.

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.

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