A comprehensive study of type I (thermonuclear) bursts in the new transient SRGA J144459.2$-$604207

Fuente: arXiv
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Autori principali: Fu, Tao, Li, Zhaosheng, Pan, Yuanyue, Ji, Long, Chen, Yupeng, Kuiper, Lucien, Galloway, Duncan K., Falanga, Maurizio, Xu, Renxin, Li, Xiaobo, Ge, Mingyu, Song, L. M., Zhang, Shu, Zhang, Shuang-Nan
Natura: Preprint
Pubblicazione: 2024
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author Fu, Tao
Li, Zhaosheng
Pan, Yuanyue
Ji, Long
Chen, Yupeng
Kuiper, Lucien
Galloway, Duncan K.
Falanga, Maurizio
Xu, Renxin
Li, Xiaobo
Ge, Mingyu
Song, L. M.
Zhang, Shu
Zhang, Shuang-Nan
author_facet Fu, Tao
Li, Zhaosheng
Pan, Yuanyue
Ji, Long
Chen, Yupeng
Kuiper, Lucien
Galloway, Duncan K.
Falanga, Maurizio
Xu, Renxin
Li, Xiaobo
Ge, Mingyu
Song, L. M.
Zhang, Shu
Zhang, Shuang-Nan
contents We report an analysis of Insight-HXMT observations of the newly discovered accreting millisecond pulsar SRGA J144459.2$-$604207. During the outburst, detected in 2024 February by SRG/ART-XC, the broadband persistent spectrum was well fitted by an absorbed Comptonization model. We detected 60 type I X-ray bursts in the Insight-HXMT medium energy (ME) data, and 37 were also detected with the low-energy (LE) telescope. By superimposing the Insight-HXMT/LE/ME/HE light curves of 37 bursts with similar profiles and intensities, we measured a deficit of X-rays in the $40-70$ keV energy band. By analyzing the time-resolved X-ray burst spectra, we determine the mean ratio of persistent to burst flux of $α=71\pm7$. We estimate the average hydrogen mass fraction in the fuel at ignition, as $\bar{X} =0.342\pm0.033$, and constrain the burst fuel composition as $X_0\leq0.4$. We found that 14 out of 60 X-ray bursts exhibited photospheric expansion, and thus we estimated the distance to the source as $10.0\pm0.71$ kpc. Combined with IXPE observations, the burst recurrence time increased from 1.55 to 8 hr as the local mass accretion rate decreased, which can be described as $ΔT_{\rm rec}\sim \dot{m}^{-0.91\pm0.02}$.
format Preprint
id arxiv_https___arxiv_org_abs_2412_05779
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A comprehensive study of type I (thermonuclear) bursts in the new transient SRGA J144459.2$-$604207
Fu, Tao
Li, Zhaosheng
Pan, Yuanyue
Ji, Long
Chen, Yupeng
Kuiper, Lucien
Galloway, Duncan K.
Falanga, Maurizio
Xu, Renxin
Li, Xiaobo
Ge, Mingyu
Song, L. M.
Zhang, Shu
Zhang, Shuang-Nan
High Energy Astrophysical Phenomena
We report an analysis of Insight-HXMT observations of the newly discovered accreting millisecond pulsar SRGA J144459.2$-$604207. During the outburst, detected in 2024 February by SRG/ART-XC, the broadband persistent spectrum was well fitted by an absorbed Comptonization model. We detected 60 type I X-ray bursts in the Insight-HXMT medium energy (ME) data, and 37 were also detected with the low-energy (LE) telescope. By superimposing the Insight-HXMT/LE/ME/HE light curves of 37 bursts with similar profiles and intensities, we measured a deficit of X-rays in the $40-70$ keV energy band. By analyzing the time-resolved X-ray burst spectra, we determine the mean ratio of persistent to burst flux of $α=71\pm7$. We estimate the average hydrogen mass fraction in the fuel at ignition, as $\bar{X} =0.342\pm0.033$, and constrain the burst fuel composition as $X_0\leq0.4$. We found that 14 out of 60 X-ray bursts exhibited photospheric expansion, and thus we estimated the distance to the source as $10.0\pm0.71$ kpc. Combined with IXPE observations, the burst recurrence time increased from 1.55 to 8 hr as the local mass accretion rate decreased, which can be described as $ΔT_{\rm rec}\sim \dot{m}^{-0.91\pm0.02}$.
title A comprehensive study of type I (thermonuclear) bursts in the new transient SRGA J144459.2$-$604207
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2412.05779