Unveiling the Temporal Properties of MAXI J1820+070 through AstroSat Observations

Mudambi, Sneha Prakash; Maqbool, Bari; Misra, Ranjeev; Hebbar, Sabhya; Yadav, J. S.; Gudennavar, S. B.; Bubbly, S. G.

doi:10.3847/2041-8213/ab66bc

Cited by 27 publications

(25 citation statements)

References 46 publications

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“…A similar feature has also been found in the LAXPC spectra of other sources (see e.g., Sharma et al 2020;Banerjee et al 2020). We also added a larger systematic (3%) value to account for uncertainties in response calibration over such a wide energy band 4-70 keV (see e.g., Mudambi et al 2020). Additional systematic residuals at low energies were also observed, therefore, following Tao et al (2019) we added an additional black-body component (bbodyrad) to the spectra.…”

Section: Spectral Analysis and Resultsmentioning

confidence: 99%

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

Beri

Naik

Singh

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Swift J0243.6+6124, the first Galactic ultra-luminous X-ray pulsar, was observed during its 2017-2018 outburst with AstroSat at both sub- and super-Eddington levels of accretion with X-ray luminosities of LX ∼ 7 × 1037 and 6 × 1038 ergs−1, respectively. Our broadband timing and spectral observations show that X-ray pulsations at ${\sim } 9.85 \rm {s}$ have been detected up to 150 keV when the source was accreting at the super-Eddington level. The pulse profiles are a strong function of both energy and source luminosity, showing a double-peaked profile with pulse fraction increasing from ∼ $10{\%}$ at $1.65 \rm {keV}$ to 40–80 % at $70 \rm {keV}$. The continuum X-ray spectra are well-modeled with a high energy cut-off power law (Γ ∼ 0.6-0.7) and one or two blackbody components with temperatures of ∼ 0.35 $\rm {keV}$ and $1.2 \rm {keV}$, depending on the accretion level. No iron line emission is observed at sub-Eddington level, while a broad emission feature at around 6.9 keV is observed at the super-Eddington level, along with a blackbody radius ($121-142 \rm {km}$) that indicates the presence of optically thick outflows.

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Section: Spectral Analysis and Resultsmentioning

confidence: 99%

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

Beri

Naik

Singh

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…MAXI J1820+070 has been found to be highly variable down to sub-second time-scales in the X-ray and optical bands (Kajava et al 2019;Paice et al 2019;Mudambi et al 2020;Stiele & Kong 2020;B u i s s o ne ta l .2021). In this work, we focus on connecting variability from across the electromagnetic spectrum, combining fast timing observations at radio, sub-mm, infrared, optical, and X-ray frequencies.…”

Section: Maxi J1820+070mentioning

confidence: 99%

Measuring fundamental jet properties with multiwavelength fast timing of the black hole X-ray binary MAXI J1820+070

Tetarenko

Casella

Miller-Jones

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We present multi-wavelength fast timing observations of the black hole X-ray binary MAXI J1820+070 (ASASSN-18ey), taken with the Karl G. Jansky Very Large Array (VLA), Atacama Large Millimeter/Sub-Millimeter Array (ALMA), Very Large Telescope (VLT), New Technology Telescope (NTT), Neutron Star Interior Composition Explorer (NICER), and XMM-Newton. Our data set simultaneously samples ten different electromagnetic bands (radio – X-ray) over a 7-hour period during the hard state of the 2018–2019 outburst. The emission we observe is highly variable, displaying multiple rapid flaring episodes. To characterize the variability properties in our data, we implemented a combination of cross-correlation and Fourier analyses. We find that the emission is highly correlated between different bands, measuring time-lags ranging from hundreds of milliseconds between the X-ray/optical bands to minutes between the radio/sub-mm bands. Our Fourier analysis also revealed, for the first time in a black hole X-ray binary, an evolving power spectral shape with electromagnetic frequency. Through modelling these variability properties, we find that MAXI J1820+070 launches a highly relativistic ($\Gamma =6.81^{+1.06}_{-1.15}$) and confined ($\phi =0.45^{+0.13}_{-0.11}$ deg) jet, which is carrying a significant amount of power away from the system (equivalent to ∼0.6 L1 − 100keV). We additionally place constraints on the jet composition and magnetic field strength in the innermost jet base region. Overall, this work demonstrates that time-domain analysis is a powerful diagnostic tool for probing jet physics, where we can accurately measure jet properties with time-domain measurements alone.

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“…bool et al 2019; Jithesh et al 2019;Mudambi et al 2020;Jithesh et al 2021). Flux resolved spectroscopy using sensitive instruments like NuSTAR for a larger sample of AGN with more continuous monitoring, will reveal the nature of the variability of these sources.…”

Section: Discussionmentioning

confidence: 99%

Evidence for coronal temperature variation in Seyfert 2 ESO 103--035 using NuSTAR observations

Barua,

Jithesh,

Misra

et al. 2021

Preprint

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We report flux-resolved spectroscopic analysis of the active galactic nucleus (AGN) ESO 103-035 using NuSTAR observations. Following an earlier work, we fit the spectra using a thermal Comptonization model with a relativistic reflection component to obtain estimates of the coronal temperature for two flux levels. The coronal temperature was found to increase from 24.0 +6.8 −3.4 to 55.3 +54.6 −7.2 keV (errors at 1-σ confidence level) as the flux increased from 9.8 to 11.9 × 10 −11 erg cm −2 s −1 in the 3-78 keV band. A marginal variation in the high energy photon index allows for both, a non-varying optical depth and for the optical depth to have varied by a factor of ∼2. This is in contrast to a previous work on NuSTAR flux resolved spectroscopy of the AGN, Ark 564, where the temperature was found to decrease with flux along with a 10% variation in the optical depth. The results maybe understood in a framework where AGN variability is either dominated by coronal heating variation leading to correlated increase of temperature with flux and the opposite effect being seen when the variability is dominated by changes in the seed photon flux.

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Unveiling the Temporal Properties of MAXI J1820+070 through AstroSat Observations

Cited by 27 publications

References 46 publications

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

Measuring fundamental jet properties with multiwavelength fast timing of the black hole X-ray binary MAXI J1820+070

Evidence for coronal temperature variation in Seyfert 2 ESO 103--035 using NuSTAR observations

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