Insight-HXMT observation on 4U 1608–52: Evolving spectral properties of a bright type-I X-ray burst

Chen, Y.P.; Zhang, S.; Ji, Long; Kong, L. D.; Santangelo, A.; Qu, J. L.; Lu, Fangjun; Li, T.P.; Song, L. M.; Xu, Yupeng; Cao, X. L.; Liu, C.Z.; Bu, Q. C.; Cai, C.; Chang, Zhi; Chen, G.; Chen, L.; Chen, T.X.; Chen, Y.B.; Cui, Wei; Deng, J. K.; Dong, Yanting; Du, Yan-Qi; Fu, M. X.; Gao, G. H.; Gao, He; Gao, Min; Ge, M. Y.; Gu, Y. D.; Guan, J.; Guo, Chengcheng; Han, Danxiang; Huang, Y.; Jia, Haiqiang; Jia, S. M.; Jiang, Luhua; Jiang, Weichun; Jin, J.; Li, B.; Li, C.K.; Li, G.; Li, M.S.; Li, W.; Li, X.; Li, X.B.; Li, Y.G.; Li, Z.W.; Liang, X. H.; Liao, J. Y.; Liu, G.Q.; Liu, H.W.; Liu, X.J.; Liu, Y.N.; Lü, Bo; Lu, X. F.; Luo, Q.; Luo, T.; Ma, Xiang; Meng, Bin; Nang, Y.; Nie, J. Y.; Ou, G.; Ren, Xiaokang; Sai, N.; Sun, Liang; Tan, Ying; Tao, Lian; Tuo, Y. L.; Wang, C.; Wang, G.F.; Wang, J.; Wang, Wangsheng; Wang, Y.S.; Wen, X. Y.; Wu, B. Y.; Wu, Mei‐Hwan; Xiao, G. C.; Xiao, Shuo; Xiong, S. L.; Yang, Jianping; Yang, S.; Yang, Yi-Jung; Yi, Q. B.; Yin, Q. Q.; You, Y.; Zhang, A.M.; Zhang, C.L.; Zhang, Faming; Zhang, H.M.; Zhang, J.; Zhang, T.; Zhang, W.C.; Zhang, W.Z.; Zhang, Yi; Zhang, Y.F.; Zhang, Z.; Zhao, H.; Zhao, X. F.; Zheng, S.; Zhou, D. K.; Zhou, Jianfeng; Zhu, Yajun

doi:10.1016/j.jheap.2019.09.001

Cited by 15 publications

(9 citation statements)

References 19 publications

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“…Prominent reflection features are iron emission lines and a soft excess (e.g. Degenaar et al 2013;in't Zand et al 2013;Keek et al 2017Keek et al , 2018Bult et al 2019;Chen et al 2019). Tracing the reflection features over time during the tail of superbursts first indicated substantial changes in the accretion disc structure (Ballantyne & Strohmayer 2004;Keek et al 2014b).…”

Section: Discussionmentioning

confidence: 99%

“…Keek et al 2016), and measurements of spectra without emission lines during a bright burst (e.g. Keek et al 2018;Chen et al 2019). 4) and the burst emission were integrated for each time interval.…”

Section: Implications For Observations Of X-ray Burstsmentioning

confidence: 99%

“…As the burst emission supersedes the coronal and boundary layer emission as the dominant radiation intercepting the accretion disc, its reflection spectrum will change likewise. During bursts, observations record a soft excess (e.g., in't Zand et al 2013;Keek et al 2018;Bult et al 2019;Chen et al 2019). In addition, Fe K and L lines may be detected during bursts (e.g., Strohmayer & Brown 2002;Degenaar et al 2013;in't Zand et al 2013;Keek et al 2014aKeek et al , 2017Bult et al 2019).…”

Section: Introductionmentioning

confidence: 99%

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Evolution of accretion disc reflection spectra due to a Type I X-ray burst

Speicher,

Ballantyne,

Fragile

2021

Preprint

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Irradiation of the accretion disc causes reflection signatures in the observed X-ray spectrum, encoding important information about the disc structure and density. A Type I X-ray burst will strongly irradiate the accretion disc and alter its properties. Previous numerical simulations predicted the evolution of the accretion disc due to an X-ray burst. Here, we process timeaveraged simulation data of six time intervals to track changes in the reflection spectrum from the burst onset to just past its peak. We divide the reflecting region of the disc within 𝑟 50 km into 6-7 radial zones for every time interval and compute the reflection spectra for each zone. We integrate these reflection spectra to obtain a total reflection spectrum per time interval. The burst ionizes and heats the disc, which gradually weakens all emission lines. Compton scattering and bremsstrahlung rates increase in the disc during the burst rise, and the soft excess at <3 keV rises from ≈ 4% to ≈ 38% of the total emission at the burst peak. A soft excess is expected to be ubiquitous in the reflection spectra of X-ray bursts. Structural disc changes such as inflation because of heating or drainage of the inner disc due to Poynting-Robertson drag affect the strength of the soft excess. Further studies on the dependence of the reflection spectrum characteristics to changes in the accretion disc during an X-ray burst may lead to probes of the disc geometry.

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Section: Discussionmentioning

confidence: 99%

Section: Implications For Observations Of X-ray Burstsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evolution of accretion disc reflection spectra due to a Type I X-ray burst

Speicher,

Ballantyne,

Fragile

2021

Preprint

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“…Among some of the thousands of observed bursts (Galloway et al 2020), observations of bursters by RXTE (Ballantyne & Strohmayer 2004;in't Zand et al 2013;Worpel et al 2013;Keek et al 2014), INTEGRAL (Sánchez-Fernández et al 2020, NICER (Keek et al 2018a(Keek et al , 2018b, AstroSat (Bhattacharyya et al 2018), and Insight-HXMT (Chen et al 2018(Chen et al , 2019 revealed interactions between the burst emission and the accretion environment: The continuum spectrum was observed to have an enhancement at soft X-rays and/or a shortage at hard X-rays (Chen et al 2012;Ji et al 2013;Worpel et al 2013Worpel et al , 2015. Such spectral deviations are considered to be burst-induced and might be relevant to disk reflection, accretion rate increase, and corona cooling (Ballantyne & Strohmayer 2004;Keek et al 2014;Degenaar et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Insight-HXMT Observation of 4U 1608–52: Evidence of Interplay between a Thermonuclear Burst and Accretion Environment

Chen

Zhang

et al. 2022

ApJ

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A Type I burst could influence the accretion process through radiation pressure and Comptonization both for the accretion disk and the corona/boundary layer of an X-ray binary, and vice versa. We investigate the temporal evolution of a bright photospheric radius expansion (PRE) burst of 4U 1608–52 detected by Insight-HXMT in 1–50 keV, with the aim to study the interplay between the burst and persistent emission. Apart from the emission from the neutron star (NS) surface, we find residuals in both the soft (<3 keV) and hard (>10 keV) X-ray bands. Time-resolved spectroscopy reveals that the excess can be attributed to either an enhanced preburst/persistent emission or the Comptonization of the burst emission by the corona/boundary layer. The Comptonization model is a convolution thermal-Comptonization model (thcomp in XSPEC), and the Comptonization parameters are fixed at the values derived from the persistent emission. We find, during the PRE phase, after the enhanced preburst/persistent emission or the Comptonization of the burst emission is removed, the NS surface emission shows a plateau and then a rise until the photosphere touches down on the NS surface, resulting in a flux peak at that moment. We speculate that the findings above correspond to the lower part of the NS surface that is obscured by the disk being exposed to the line of sight due to the evaporation of inner disk by the burst emission. The consistency between the f a model and convolution thermal-Comptonization model indicates the interplay between thermonuclear bursts and accretion environments. These phenomena do not usually show up in conventional blackbody model fittings, which may be due to the low count rate and narrow energy coverage in previous observations.

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“…Together with the technical aspects, some first results are also covered in this special collection. One of those are the Insight-HXMT observation on 4U 1608-52 [11]. In this paper, Chen et al reported on a photospheric radius expansion burst, finding that the burst and enhanced persistent emissions sum up to exceed Eddington luminosity by 40%, speculating that the emission comes from beyond the photospheric radius, or through the Comptonization of the corona Insight-HXMT observations on the 2019 outburst from the X-ray pulsar 4U 1901+03 are also reported in a paper of this collection [13].…”

mentioning

confidence: 99%

Introducing a special collection of papers in the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite: Insight-HXMT

Torres¹,

Zhang²

2020

Preprint

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Insight-HXMT is the first Chinese X-ray astronomical mission, launched successfully on June 15, 2017, from China's Jiuquan Satellite Launch Center. Insight-HXMT was designed to have a broad energy coverage in Xrays, from 1-250 keV, with excellent timing and adequate energy resolution at soft X-rays, and the largest effective area at hard X-rays. This allows, in particular, to observe bright sources like X-ray binaries (XRBs) in their bright/outburst states with high cadence and high statistics at hard and soft X-rays at once. It was then expected that the Insight-HXMT mission will bring us new insights regarding the characteristics of several source classes. Examples include characterizing High-Mass X-ray Binaries (HMXBs) and the outburst evolution of Low-Mass X-ray Binaries (LMXBs). For instance, in HMXB systems, the region around their Alfven radius that is responsible to determine whether accretion or propeller occurs, or the region around the NS magnetic pole where the intense X-rays are supposed to be produced are specially appealing targets of study. For the LMXBs, the evolution the outburst and the properties of the compact objects themselves are obvious priority targets for Insight-HXMT. Due to the broad coverage in energy, Insight-HXMT is specially well suited to study the influence of thermonuclear (type-I) X-ray bursts upon the surrounding environment.Observations from Insight-HXMT are producing stateof-the-art samples in a broad energy band, covering both the timing and energetic domains. Besides, so far the largest effective area at MeV, i.e, in soft gamma-rays, of the anti-coincidence detector CsI of Insight-HXMT, provides an almost unique power in monitoring flare events like Gamma-Ray Bursts (GRBs), especially short/hard GRBs suggested to be generated in binary neutron star mergers. We are proud to present a collection of papers of the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite Insight-HXMT.These papers cover the in-orbit performance, the background model, and all calibration results, which will serve as primary references of future observations and data analysis with Insight-HXMT, expected to operate in space for several more years to come. Then, the special issue contains details of instrument calibration, both in

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Insight-HXMT observation on 4U 1608–52: Evolving spectral properties of a bright type-I X-ray burst

Cited by 15 publications

References 19 publications

Evolution of accretion disc reflection spectra due to a Type I X-ray burst

Evolution of accretion disc reflection spectra due to a Type I X-ray burst

Insight-HXMT Observation of 4U 1608–52: Evidence of Interplay between a Thermonuclear Burst and Accretion Environment

Introducing a special collection of papers in the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite: Insight-HXMT

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