Correlating spectral and timing properties in the evolving jet of the microblazar MAXI J1836-194
23 Jan 2021-Monthly Notices of the Royal Astronomical Society (Oxford University Press (OUP))-Vol. 501, Iss: 4, pp 5910-5926
TL;DR: In this article, the authors explore the disc-jet connection by modeling the multi-wavelength emission of MAXI J1836-194 during its 2011 outburst and find that the properties of the X-ray power spectrum are correlated with the jet properties, suggesting that an underlying physical process regulates both.
Abstract: During outbursts, the observational properties of black hole X-ray binaries vary on time-scales of days to months. These relatively short time-scales make these systems ideal laboratories to probe the coupling between accreting material and outflowing jets as the accretion rate varies. In particular, the origin of the hard X-ray emission is poorly understood and highly debated. This spectral component, which has a power-law shape, is due to Comptonization of photons near the black hole, but it is unclear whether it originates in the accretion flow itself, or at the base of the jet, or possibly the interface region between them. In this paper, we explore the disc-jet connection by modelling the multiwavelength emission of MAXI J1836-194 during its 2011 outburst. We combine radio through X-ray spectra, X-ray timing information, and a robust joint-fitting method to better isolate the jet's physical properties. Our results demonstrate that the jet base can produce power-law hard X-ray emission in this system/outburst, provided that its base is fairly compact and that the temperatures of the emitting electrons are subrelativistic. Because of energetic considerations, our model favours mildly pair-loaded jets carrying at least 20 pairs per proton. Finally, we find that the properties of the X-ray power spectrum are correlated with the jet properties, suggesting that an underlying physical process regulates both.
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Max Planck Society1, Radboud University Nijmegen2, University of Würzburg3, Smithsonian Institution4, Harvard University5, Massachusetts Institute of Technology6, Yale University7, California Institute of Technology8, Princeton University9, University of Arizona10, University of Amsterdam11, York University12, Columbia University13, Australia Telescope National Facility14, Goethe University Frankfurt15, Spanish National Research Council16, Leiden University17, Academia Sinica18, INAF19, Polish Academy of Sciences20, Shanghai Jiao Tong University21, University of Waterloo22, University of Concepción23, Joint Institute for VLBI in Europe24
TL;DR: In this paper, a very long-baseline interferometry (VLBI) image of the Centaurus A nucleus was obtained with the Event Horizon Telescope at 228 GHz, which revealed a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet.
Abstract: Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5,6. The millimetre image of the Centaurus A nucleus by the Event Horizon Telescope reveals a highly collimated, asymmetrically edge-brightened jet. The source’s event horizon shadow should be visible at terahertz frequencies, consistent with the universal scale invariance of black holes.
37 citations
TL;DR: In this paper, the authors analyzed 5 epochs of NICER data of the black hole X-ray binary MAXI J1820+070 during the bright hard-to-soft state transition in its 2018 outburst with both reflection spectroscopy and Fourier-resolved timing analysis.
Abstract: We analyze 5 epochs of NICER data of the black hole X-ray binary MAXI J1820+070 during the bright hard-to-soft state transition in its 2018 outburst with both reflection spectroscopy and Fourier-resolved timing analysis. We confirm the previous discovery of reverberation lags in the hard state, and find that the frequency range where the (soft) reverberation lag dominates decreases with the reverberation lag amplitude increasing during the transition, suggesting an increasing X-ray emitting region, possibly due to an expanding corona. By jointly fitting the lag-energy spectra in a number of broad frequency ranges with the reverberation model reltrans, we find the increase in reverberation lag is best described by an increase in the X-ray coronal height. This result, along with the finding that the corona contracts in the hard state, suggests a close relationship between spatial extent of the X-ray corona and the radio jet. We find the corona expansion (as probed by reverberation) precedes a radio flare by ~5 days, which may suggest that the hard-to-soft transition is marked by the corona expanding vertically and launching a jet knot that propagates along the jet stream at relativistic velocities.
35 citations
TL;DR: In this paper , the authors performed a systematic search of all NICER archival observations of black hole low-mass X-ray binaries for signatures of reverberation and found that reverberation lags become longer and dominate at lower Fourier frequencies during the hard-to-soft state transition.
Abstract: We perform the first systematic search of all NICER archival observations of black hole (and candidate) low-mass X-ray binaries for signatures of reverberation. Reverberation lags result from the light travel time difference between the direct coronal emission and the reflected disk component, and therefore their properties are a useful probe of the disk-corona geometry. We detect new signatures of reverberation lags in eight sources, increasing the total sample from three to 11, and study the evolution of reverberation lag properties as the sources evolve in outbursts. We find that in all of the nine sources with more than one reverberation lag detection, the reverberation lags become longer and dominate at lower Fourier frequencies during the hard-to-soft state transition. This result shows that the evolution in reverberation lags is a global property of the state transitions of black hole low-mass X-ray binaries, which is valuable in constraining models of such state transitions. The reverberation lag evolution suggests that the corona is the base of a jet that vertically expands and/or gets ejected during state transition. We also discover that in the hard state, the reverberation lags get shorter, just as the quasiperiodic oscillations (QPOs) move to higher frequencies, but then in the state transition, while the QPOs continue to higher frequencies, the lags get longer. We discuss the implications of the coronal geometry and physical models of QPOs in light of this new finding.
12 citations
TL;DR: In this paper , the authors studied the jet in the hard state of the accreting black-hole binary MAXI J1820+070 and derived the jet Lorentz factor from the available radio-to-optical spectral and variability data.
Abstract: We study the jet in the hard state of the accreting black-hole binary MAXI J1820+070. From the available radio-to-optical spectral and variability data, we put strong constraints on the jet parameters. We find while it is not possible to uniquely determine the jet Lorentz factor from the spectral and variability properties alone, we can estimate the jet opening angle ($\approx 1.5\pm1^\circ$), the distance at which the jet starts emitting synchrotron radiation ($\sim 3 \times10^{10}$cm), and the magnetic field strength there ($\sim$10$^4$G), with relatively low uncertainty, as they depend weakly on the bulk Lorentz factor. We find the breaks in the variability power spectra from radio to sub-mm are consistent with variability damping over the time scale equal to the travel time along the jet at any Lorentz factor. This factor can still be constrained by the electron-positron pair production rate within the jet base, which we calculate based on the observed X-ray/soft gamma-ray spectrum, and the jet power, required to be less than the accretion power. The minimum ($\sim$1.5) and maximum ($\sim$4.5) Lorentz factors correspond to the dominance of pairs and ions, and the minimum and maximum jet power, respectively. We estimate the magnetic flux threading the black hole and find the jet can be powered by the Blandford-Znajek mechanism in a magnetically-arrested flow accretion flow. We point out the similarity of our derived formalism to that of core shifts, observed in extragalactic radio sources.
10 citations
University of Oxford1, INAF2, Université Paris-Saclay3, University of Toulouse4, European Space Agency5, University of Paris6, University of Tübingen7, University of Turku8, European Space Research and Technology Centre9, University of Maryland, Baltimore County10, Goddard Space Flight Center11, University of Erlangen-Nuremberg12
TL;DR: In this article, the authors present a review of the scientific literature based on the INTEGRAL data, which has significantly advanced our knowledge in the field of relativistic astrophysics.
Abstract: INTEGRAL is an ESA mission in fundamental astrophysics that was launched in October 2002. It has been in orbit for over 18 years, during which it has been observing the high-energy sky with a set of instruments specifically designed to probe the emission from hard X-ray and soft gamma-ray sources. This paper is devoted to the subject of black hole binaries, which are among the most important sources that populate the high-energy sky. We present a review of the scientific literature based on INTEGRAL data, which has significantly advanced our knowledge in the field of relativistic astrophysics. We briefly summarise the state-of-the-art of the study of black hole binaries, with a particular focus on the topics closer to the INTEGRAL science. We then give an overview of the results obtained by INTEGRAL and by other observatories on a number of sources of importance in the field. Finally, we review the main results obtained over the past 18 years on all the black hole binaries that INTEGRAL has observed. We conclude with a summary of the main contributions of INTEGRAL to the field, and on the future perspectives.
7 citations
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TL;DR: In this paper, the authors review the properties and behavior of 20 X-ray binaries that contain a dynamically confirmed black hole, 17 of which are transient systems, during the past decade, many of these transien...
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TL;DR: In this article, the relativistic motion of a quasi-steady jet is modeled as a superluminal expansion in which the moving component and the stationary component would have comparable Doppler-boosted fluxes, and specific models for the dynamical and radiative properties of the jet and individual shocks are presented.
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1,908 citations