# Ling-Da Kong's research while affiliated with Chinese Academy of Sciences and other places

## Publications (23)

Article
Full-text available
Staying in quiescence for 49 yr, 4U 1730–22 became active and had two outbursts in 2021 and 2022; 10 thermonuclear X-ray bursts were detected with Insight-HXMT. Among them, the faintest burst showed a double-peaked profile, placing the source as the seventh accreting neutron star (NS) exhibiting double-peaked type I X-ray bursts; the other bursts s...
Article
Full-text available
After 49 yr of quiescence, 4U 1730–22 became active and had two outbursts in 2021 and 2022; the onset and tail of the outbursts were observed by NICER, which give us a peerless opportunity to study the state transition and its underlying mechanism. In this work, we take both the neutron star (NS) surface and accretion disk emission as the seed phot...
Preprint
Full-text available
We present a systematic analysis of type C quasi-periodic oscillation (QPO) observations of H 1743--322 throughout the Rossi X-ray Timing Explorer (RXTE) era. We find that, while different outbursts have significant flux differences, they show consistent positive correlations between the QPO fractional root-mean-square (rms) amplitude and non-therm...
Preprint
Full-text available
After in quiescence for 49 years, 4U~1730--22 became active and had two outbursts in 2021 \& 2022, the onset and tail of the outbursts were observed by NICER, which give us a peerless opportunity to study the state transition and its underlying mechanism. In this work, we take both the NS surface and accretion disk emission as the seed photons of t...
Preprint
Full-text available
After in quiescence for 49 years, 4U~1730--22 became active and had two outbursts in 2021 \& 2022; ten thermonuclear X-ray bursts were detected with Insight-HXMT. Among them, the faintest burst showed a double-peaked profile, placing the source as the 5th accreting neutron star (NS) exhibiting double/triple-peaked type-I X-ray bursts; the other bur...
Article
Full-text available
MAXI J1816–195 is a newly discovered accreting millisecond pulsar with prolific thermonuclear bursts, detected during its outburst in 2022 June by Insight-HXMT and NICER. During the outburst, Insight-HXMT detected 73 bursts in its peak and decay phase, serving as a prolific burst system found in the accreting millisecond pulsars. By analyzing one b...
Article
Full-text available
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...
Preprint
Full-text available
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...
Article
Full-text available
The detection of cyclotron resonance scattering features (CRSFs) is the only way to directly and reliably measure the magnetic field near the surface of a neutron star (NS). The broad energy coverage and large collection area of Insight-HXMT in the hard X-ray band allowed us to detect the CRSF with the highest energy known to date, reaching about 1...
Preprint
Full-text available
The detection of cyclotron resonance scattering features (CRSFs) is the only way to directly and reliably measure the magnetic field near the surface of a neutron star (NS). The broad energy coverage and large collection area of \emph{Insight}-HXMT in the hard X-ray band allowed us to detect the CRSF with the highest energy known to date, reaching...
Article
Full-text available
We have performed phase-resolved spectral analysis of the accreting pulsar 1A 0535+262 based on observations of Insight-HXMT during the 2020 type II outburst of the source. We focus on the two-dimensional dependence of the cyclotron resonance scattering features (CRSFs) along the outburst time and at different phases. The fundamental CRSF line (f-C...
Preprint
We have performed phase-resolved spectral analysis of the accreting pulsar 1A~0535+262 based on observations of Insight-HXMT during the 2020 Type-II outburst of the source. We focus on the two-dimensional dependence of the cyclotron resonance scattering features (CRSFs) along the outburst time and at different phases. The fundamental CRSF line (f-C...
Preprint
PSR B1259-63 is a $\gamma$-ray binary system, where the compact object is a pulsar. The system has an orbital period of 1236.7 days and shows peculiar $\gamma$-ray flares (in 100\,MeV--300\,GeV) after its periastron time. We analyzed the \textit{Fermi}-LAT observation of PSR B1259-63 during its latest periastron passage, as well as its previous thr...
Article
Full-text available
PSR B1259-63 is a γ-ray binary system, where the compact object is a pulsar. The system has an orbital period of 1236.7 days and shows peculiar γ-ray flares (in 100 MeV–300 GeV) after its periastron time. We analyzed the Fermi-LAT observation of PSR B1259-63 during its latest periastron passage, as well as its previous three periastrons. The bright...
Article
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846–031 during its outburst in 2019 with the observations of Insight -HXMT, NICER and MAXI . This outburst can be classified roughly into four different states. Type-C quasi-periodic oscillations (QPOs) observed by NICER (about 0.1–6 Hz) and Insigh...
Article
Full-text available
Low-frequency quasiperiodic oscillations (LFQPOs) are commonly found in black hole X-ray binaries, and their origin is still under debate. The properties of LFQPOs at high energies (above 30 keV) are closely related to the nature of the accretion flow in the innermost regions, and thus play a crucial role in critically testing various theoretical m...
Preprint
Full-text available
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT, NICER and MAXI. This outburst can be classfied roughly into four different states. Type-C quasi-periodic oscillations (QPOs) observed by NICER (about 0.1-6Hz) and Insight-HX...
Preprint
Full-text available
Low-frequency quasi-periodic oscillations (LFQPOs) are commonly found in black hole X-ray binaries, and their origin is still under debate. The properties of LFQPOs at high energies (above 30 keV) are closely related to the nature of the accretion flow in the innermost regions, and thus play a crucial role in critically testing various theoretical...
Article
Recently, the system parameters of Cygnus X-1, i.e., the black hole mass M, the orbital inclination i and the source distance D, have been updated. As the input constraints of the continuum-fitting method, it is necessary to refine the spin with these new parameters. The Hard X-ray Modulation Telescope (HXMT, also named Insight) was successfully la...
Article
LS 5039 is a well-known γ -ray binary system which consists of an unknown compact object and a massive companion O star. It shows rather stable emissions at high energies over years and hence serves as an ideal laboratory to investigate the emission mechanism for such peculiar systems which emit prominent γ -rays. To this end, we take the orbital p...
Preprint
Full-text available
The Hard X-ray Modulation Telescope (HXMT) named Insight is China's first X-ray astronomical satellite. The Low Energy X-ray Telescope (LE) is one of its main payloads onboard. The detectors of LE adopt swept charge device CCD236 with L-shaped transfer electrodes. Charges in detection area are read out continuously along specific paths, which leads...
Article
The Hard X-ray Modulation Telescope (HXMT) named Insight is China's first X-ray astronomical satellite. The Low Energy X-ray Telescope (LE) is one of its main pay-loads onboard. The detectors of LE adopt swept charge device CCD236 with L-shaped transfer electrodes. Charges in detection area are read out continuously along specific paths, which lead...
Preprint
Full-text available
LS 5039 is a well-known $\gamma$-ray binary system which consists of an unknown compact object and a massive companion O star. It shows rather stable emissions at high energies over years and hence serves as an ideal laboratory for investigating the emission mechanism for such peculiar systems which emit prominent $\gamma$-rays. To this end, we tak...

## Citations

... Israel et al. 2017a,b, Brice et al. 2021), a situation now confirmed in the case of Swift J0243.6+6124 (Kong et al., 2022). ...
... In their approach, the seed photons' temperature of the Comptt model is tied with the temperature of the blackbody/ burst emission. The updated Comptonization model is also used in the burst spectral fitting in 4U 1608-52 (Chen et al. 2022). Thus, the convolution thermal-Comptonization model (with an input seed photon spectrum of blackbody) has the same d.o.f. as the canonical blackbody model and more d.o.f. ...
... In this work, we analyze the three giant outbursts, in 2009, 2011 and 2020, and the previous doublepeaked outburst of 1A 0535+262. The time span of each outburst was defined by investigating the X-ray light curves presented in the literature (Acciari et al. 2011;Sartore et al. 2015;Mandal & Pal 2022;Kong et al. 2022). We perform a deep search for gamma-ray emission and pulsations from 1A 0535+262 using more than 13 years of Fermi-LAT data and the latest 12-year source catalog. ...
... Interaction of the pulsar wind with the outflow from the Be star leads to radiation in the range from radio to hard gamma rays with photon energy at least 10 TeV ( [21][22][23][24][25][26][27][28][29]). GeV flares 30-60 days after the passage of the periastron in 2010 [30], 2014 [29], 2017 [31,32] and in 2021 [33] are one of the most spectacular phenomena in this system. The luminosity of the system during these flares is comparable with the total rotational losses of the pulsar PSR 1259-63. ...
... If the NS spin axis of 1A 0535 + 262 is also inclined with respect to the orbital spin, we would expect that this system would precess around the spin axis and may produce the QPO signal in the accretion process, similar to the generation of low-frequency QPOs in some black hole systems (e.g. Ingram & Done 2011 ;Ingram et al. 2016 ;Huang et al. 2018 ;Liu et al. 2021 ). In this picture, the generation of QPO's two-peak structure would be the result of BF, and the difference between the two peaks would be the spin frequency of the NS or twice that. ...
... Zhang et al. (2022) has applied the same model using Insight-HXMT observations of the type-C QPO in MAXI J1535 up to 150 keV. The rationale behind applying this model to type-C in BHXB is that the fractional rms amplitude of these QPOs can be as large as ∼ 15% up to ∼200 keV (Ma et al. 2021). At those energies, Comptonization dominates the emission in these systems (e.g., the disc and the reflection component peak at, respectively, ∼1−3 keV and ∼ 20−25 keV and both drop quickly above that), and hence Comptonization is most likely responsible for the rms amplitude and lags of the QPO. ...
... The dataset from both satellites are not affected by photon pile-up effects. Similar spectra analysis of Cyg X-1 (Zhao et al. 2020) and MAXI J1820-070 (You et al. 2021;Zhao et al. 2021;Guan et al. 2021) using HXMT have been reported. The paper is organized as follows: in Section 2, we describe the detail of observations and data reduction; the data analysis and results are presented in Section 3; Section 4 includes discussions and Section 5 includes conclusions. ...