X-ray spectral evolution in an X-ray changing-look AGN NGC 1365 with variable column density

Liu, Hao; Wu, Qingwen; Xue, Yongquan; Wang, Tinggui; Yang, Jun; Guo, Hengxiao; He, Zhicheng

doi:10.1088/1674-4527/21/8/199

Cited by 4 publications

(1 citation statement)

References 71 publications

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“…Actually, this AGN is classified as Seyfert 1, 1.5, 1.8 or 2 in the literature (e.g., Veron et al (1980); Turner et al (1993); Maiolino & Rieke (1995); Risaliti et al (2007); Thomas et al (2017)) due to variation in the X-ray flux and the column density of the absorbers along the line of sight (Hernández- García, L. et al 2015). Apart from the scenario of dust clouds in BLR, disk winds have recently been used as a mechanism to explain the variable column density (Connolly et al 2014;Braito et al 2014;Liu et al 2021;Mondal et al 2022). In this work, we study X-ray/UV variation and also investigate the off-nuclear X-ray sources in NGC 1365 as Ultraluminous X-ray sources (ULXs) are associated with star formation.…”

Section: Introductionmentioning

confidence: 99%

Multi-wavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

Swain,

Dewangan,

Shalima

et al. 2023

Preprint

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We present a multi-wavelength study of the active nucleus and the off-nuclear X-ray sources in the nearby spiral galaxy, NGC 1365 using three simultaneous UV/X-ray observations by AstroSat over a two months period and archival IR observations performed with Spitzer and Herschel. Utilising the data from the Soft X-ray Telescope (SXT) on-board AstroSat, we find spectral variability mainly caused by the variation in the X-ray column density, (N H ∼ 10 22 -10 23 cm −2 ). With the accurate spatial resolution of the UVIT onboard AstroSat, we separate the intrinsic AGN flux from the host galaxy emission and then correct for the Galactic and the internal reddening. We detect no significant variation in the NUV emission over the observation period. The AGN in FUV band is undetectable due to heavy intrinsic extinction. Further, the multi-wavelength IR/UV/X-ray AGN SED reveals that the AGN is in a low luminosity phase with accretion rate ∼ 0.01 L Edd . The steady UV emission and strong X-ray absorption variability suggest that the obscuring clouds are likely compact and affect the compact X-ray source only and do not possibly cover the extended UV emitting region. In addition, the UVIT is able to resolve two bright spots at a radius of 7 (∼ 6.3 Kpc) from the central nucleus in the South-West (SW) direction. In the UVIT image of the entire galaxy, we identify UV counterparts to four Chandra identified bright X-ray sources. One well-known ultra-luminous X-ray source (ULX) NGC 1365 X2 is identified with its UV counterpart at 86 from the nucleus in the north-east (NE) direction from the active nucleus.

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Section: Introductionmentioning

confidence: 99%

Multi-wavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

Swain,

Dewangan,

Shalima

et al. 2023

Preprint

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Multiwavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

Swain

Dewangan

Shalima

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present a multi-wavelength study of the active nucleus and the off-nuclear X-ray sources in the nearby spiral galaxy, NGC 1365 using three simultaneous UV/X-ray observations by AstroSat over a two months period and archival IR observations performed with Spitzer and Herschel. Utilising the data from the Soft X-ray Telescope (SXT) on-board AstroSat, we find spectral variability mainly caused by the variation in the X-ray column density, (NH ∼ 1022–1023 cm−2). With the accurate spatial resolution of the UVIT onboard AstroSat, we separate the intrinsic AGN flux from the host galaxy emission and then correct for the Galactic and the internal reddening. We detect no significant variation in the NUV emission over the observation period. The AGN in FUV band is undetectable due to heavy intrinsic extinction. Further, the multi-wavelength IR/UV/X-ray AGN SED reveals that the AGN is in a low luminosity phase with accretion rate ∼ 0.01 LEdd. The steady UV emission and strong X-ray absorption variability suggest that the obscuring clouds are likely compact and affect the compact X-ray source only and do not possibly cover the extended UV emitting region. In addition, the UVIT is able to resolve two bright spots at a radius of 7″ (∼6.3 Kpc) from the central nucleus in the South-West (SW) direction. In the UVIT image of the entire galaxy, we identify UV counterparts to four Chandra identified bright X-ray sources. One well-known ultra-luminous X-ray source (ULX) NGC 1365 X2 is identified with its UV counterpart at 86″ from the nucleus in the north-east (NE) direction from the active nucleus.

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The Dynamical Structure of the Outflows Driven by a Large-scale Magnetic Field

Li¹,

Cao

2022

ApJ

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A large-scale magnetic field is crucial in launching and collimating jets/outflows. It is found that the magnetic flux can be efficiently transported inward by a fast-moving corona above a thin disk. In this work, we investigate the dynamical structure of the outflows driven by the large-scale magnetic field advected by a hot corona. With the derived large-scale magnetic field, the outflow solution along every field line is obtained by solving a set of magneto-hydrodynamic equations self-consistently with boundary conditions at the upper surface of the corona. We find that the terminal speeds of the outflows driven from the inner region of the disk are ∼0.01–0.1c. The temperatures of the outflows at a large distance from the black hole are still as high as several ten keV. The properties of the magnetic outflows derived in this work are roughly consistent with the fast outflows detected in some luminous quasars and X-ray binaries (XRBs). The total mass-loss rate in the outflows from the corona is about 7%–12% of the mass-accretion rate of the disk. The three-dimensional field geometry, the velocity, temperature, and density of the outflows derived in this work can be used for calculating the emergent spectra and their polarization of the accretion disk/corona/outflow systems. Our results may help understand the features of the observed spectra of XRBs and active galactic nuclei.

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X-ray spectral evolution in an X-ray changing-look AGN NGC 1365 with variable column density

Cited by 4 publications

References 71 publications

Multi-wavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

Multi-wavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

Multiwavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources

The Dynamical Structure of the Outflows Driven by a Large-scale Magnetic Field

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