Broad-band spectral and timing properties of MAXI J1348–630 using <i>AstroSat</i> and <i>NICER</i> observations

Jithesh, V.; Misra, Ranjeev; Maqbool, Bari; Mall, Gitika

doi:10.1093/mnras/stab1307

Cited by 12 publications

(11 citation statements)

References 59 publications

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“…The disc inclination angle, constrained at i = 32.9 +4.1 −0.6 degrees, The three soft state observations are spectrally similar without showing any significant difference in the parameter values (Table 4). On the other hand, Jithesh et al (2021) shows that there are significant differences in the power density spectra of the three observations in the LAXPC (3-15 keV) band. In fact, different segments of the Data2 have significantly different variability amplitude.…”

Section: Discussionmentioning

confidence: 85%

“…They estimated the spin, black hole mass and inclination of the source by fixing the distance to 2.2 kpc, and the values were found to be 0.80 ± 0.02, 8.7 ± 0.3 M and 36.5 ± 1.0 degrees, respectively. Jithesh et al (2021) used five simultaneous AstroSat and NICER observations for studying the broadband X-ray spectral-timing properties of the source. They noted the presence of quasi-periodic oscillations of type-C and type-A classes and further via power density spectrum and energy-dependent rms, they confirmed that the disc is significantly less variable than the Comptonization component.…”

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confidence: 99%

“…Jithesh et al (2021) reported the r.m.s and time-lag as a function of energy for the hard state observations and modelled them using a single zone Comptonization model(Maqbool et al 2019). Variations of the inner disc temperature (δkT in ) and the coronal temperature (δkT e ) occur with a time difference (τ d ) between them which gives rise to the observed energy-dependent r.m.s and time-lag Jithesh et al (2021). observed that τ d is positive (∼ 70 ms) for the bright state, but it is negative τ d ∼ −90 ms, for the faint one when variations at ∼ 1 Hz…”

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confidence: 99%

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Broadband Spectral Properties of MAXI J1348–630 using AstroSat Observations

Mall¹,

Vadakkumthani²,

Misra³

2022

Res. Astron. Astrophys.

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We present broadband X-ray spectral analysis of the black hole X-ray binary MAXI J1348--630, performed using five AstroSat observations. The source was in the soft spectral state for the first three and in the hard state for the last two observations. The three soft state spectra were modelled using a relativistic thin accretion disc with reflection features and thermal Comptonization. Joint fitting of the soft state spectra constrained the spin parameter of the black hole a* > 0.97 and the disc inclination angle i = 32.9(+4.1,-0.6) degrees. The bright and faint hard states had bolometric flux a factor of ~6 and ~10 less than that of the soft state. Their spectra were fitted using the same model except that the inner disc radius was not assumed to be at the last stable orbit. However, the estimated values do not indicate large truncation radii and the inferred accretion rate in the disc was an order of magnitude lower than that of the soft state. Along with the earlier reported temporal analysis, AstroSat data provides a comprehensive picture of the evolution of the source.

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Section: Discussionmentioning

confidence: 85%

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confidence: 99%

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confidence: 99%

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Broadband Spectral Properties of MAXI J1348–630 using AstroSat Observations

Mall¹,

Vadakkumthani²,

Misra³

2022

Res. Astron. Astrophys.

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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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“…Spectro-timing properties of a new black hole transient MAXI J1348-630 have been investigated using the simultaneous/quasi-simultaneous AstroSat and NICER observations. The analysis revealed several interesting characteristics of the source, including the flip-flop behaviour, different types of QPOs and energydependent behaviour of variability components (Jithesh et al 2021). The detailed broadband spectral study using the reflection models constrained the spin and inclination of the system and the values are > 0.97 and ∼ 33 • , respectively (Mall et al 2023).…”

Section: Introductionmentioning

confidence: 96%

Spectral and temporal studies of Swift J1658.2–4242 using AstroSat observations with the JeTCAF model

Mondal

Jithesh

2023

Monthly Notices of the Royal Astronomical Society

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We present the X-ray spectral and temporal analysis of the black hole X-ray transient Swift J1658.2–4242 observed by AstroSat. Three epochs of data have been analysed using the JeTCAF model to estimate the mass accretion rates and to understand the geometry of the flow. The best-fit disc mass accretion rate ($\dot{m}_d$) varies between $0.90^{+0.02}_{-0.01}$ to $1.09^{+0.04}_{-0.03}$$\dot{M}_{\rm Edd}$ in these observations, while the halo mass accretion rate changes from $0.15^{+0.01}_{-0.01}$ to $0.25^{+0.02}_{-0.01}$$\dot{M}_{\rm Edd}$. We estimate the size of the dynamic corona, that varies substantially from $64.9^{+3.9}_{-3.1}$ to $34.5^{+2.0}_{-1.5}$rg and a moderately high jet/outflow collimation factor stipulates isotropic outflow. The inferred high disc mass accretion rate and bigger corona size indicate that the source might be in the intermediate to soft spectral state of black hole X-ray binaries. The mass of the black hole estimated from different model combinations is ∼14M⊙. In addition, we compute the quasi-periodic oscillation (QPO) frequencies from the model-fitted parameters, which match the observed QPOs. We further calculate the binary parameters of the system from the decay profile of the light curve and the spectral parameters. The estimated orbital period of the system is 4.0 ± 0.4 hr by assuming the companion as a mid or late K-type star. Our analysis using the JeTCAF model sheds light on the physical origin of the spectro-temporal behaviour of the source, and the observed properties are mainly due to the change in both the mass accretion rates and absorbing column density.

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Broad-band spectral and timing properties of MAXI J1348–630 using AstroSat and NICER observations

Cited by 12 publications

References 59 publications

Broadband Spectral Properties of MAXI J1348–630 using AstroSat Observations

Broadband Spectral Properties of MAXI J1348–630 using AstroSat Observations

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

Spectral and temporal studies of Swift J1658.2–4242 using AstroSat observations with the JeTCAF model

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